JP2001504265A - Multi-pole time-to-digital converter - Google Patents

Abstract

(57) [Summary] A device (82) for extending the dynamic range of data acquisition. Use multiple anode detectors (80) and microchannel plates (83) to extend the dynamic range of the time-to-digital converter (82). The plurality of anodes (80) determine the characteristics of the signal. In this case, there is no distortion that would normally occur in a large signal, and the detection would not be possible due to noise that would normally occur in a small signal. Absent. Data from the multi-pole detector (80) can be summed over the selectable time frames (100, 102) to create a multi-bit word.

Description

DETAILED DESCRIPTION OF THE INVENTION Multipolar Time-to-Digital Converter Background of the Invention 1. TECHNICAL FIELD The present invention relates to systems and methods for acquiring transient data from microchannel plates or pulse-based detectors. In particular, the present invention provides systems and methods for detecting, recording, and displaying time-of-flight mass spectrometry data with high temporal resolution, low noise, wide dynamic range, and improved signal averaging characteristics. 2. State of the Art To illustrate the present invention, time-of-flight (TOF) mass spectrometry is defined as the conversion of an electronically recorded mass spectrum into a chemically recognizable form. Preferably, the resulting data includes an analysis on two parameters of the mass spectral signal. The first parameter is the position of the spectral peak with respect to time, and the second is the magnitude and intensity of the peak. The first parameter represents the mass of the ion causing each peak. The second parameter is established to ensure that it is indicated by the peak height or peak area at the maximum for the high resolution scan and represents the percentage of a particular type of ion current contained in the specimen. In the following, the background of the mass spectrometer will be described in detail, but it is important to note that this description can also be applied to optical systems that detect photons instead of ions. The present invention can also improve the photon detector, as described below. Ions and photons are both referred to as molecules, and the invention relates to the detection of a stream of molecules. FIG. 1A shows an output representing information, captured and displayed by an electronic data acquisition device known to those skilled in the art as a transient digitizer. The displayed waveform 10 directly illustrates two advantages of the transient digitizer. First, an approximate value is displayed on the waveform 10 and the respective intensities 12, 14, and 16 of the detected peak values are displayed in an easy-to-understand manner as indicated by the Y axis "relative intensity" and the X axis "time". are doing. Second, the entire waveform 10 is displayed as a complete waveform retrieved from memory. One of the characteristics of the transient digitizer is that the dynamic range is excellent. As is known to those skilled in the art, dynamic range refers to the ability of a data acquisition device to detect the impact of a substance or molecule on a detector. More specifically, both large signal and small signal are acquired (detected) in a state where signal distortion that normally occurs in the case of a large signal does not occur and the signal does not become undetectable due to noise in the case of a small signal. Ability. FIG. 3A shows the structure of a transient digitizer capable of generating the graph of FIG. 1A. The transient digitizer is actually shown at 24 as the electronics associated with a single anode detector 22. Digitizer 24 is thus in electrical communication with a time-of-flight mass spectrometer (also referred to as a waveform recorder) and is generally shown at 20. The time-of-flight mass spectrometer 20 generally includes a chamber having an external vacuum housing 30 and an internal flight tube 32 as shown in a cross-sectional view. FIG. 3A shows the internal flight tube 32 in the longitudinal direction. However, the cross-section of the inner flight tube 32 may be circular, square, or any other suitable tube shape, as known to those skilled in the art of time-of-flight mass spectrometry. Through the input port 34, molecules (ions) are injected into the flight tube 32 and accelerated downward along the length of the flight tube 32. This is done by combining a pulsar 36 (also known as a pulse reflection electrode plate) with a series of field defining electrodes 38 arranged to define a path 31 within the vacuum housing 30 so that ions can move. The molecules are accelerated in flight tube 32 in the direction of microchannel plate 26 and single anode detector 22. Molecules colliding with the microchannel plate 26 are detected by the single anode detector 22 as electric pulses. This causes the single anode detector 22 to generate an electrical signal, which is processed by a transient digitizer 24 associated with the single anode detector 22. The microchannel plate 26 is shown in detail in FIG. 3B. The microchannel plates 26 are actually an array of electronic multipliers (referred to as channels 27) and are parallel to each other. The matrix of channels 27 is typically made of lead glass and is treated to optimize the secondary emission characteristics of each channel 27 and to make the walls of channel 27 semiconducting so that charge replenishment occurs. Thus, each channel 27 can be viewed as a continuous dynode structure that performs the function of its own dynode resistance chain. The parallel electrical connection to each channel 27 is made by applying a metal coating on the front and back surfaces (usually called Nichrome or Iconel), which will be the input and output electrodes. One channel 27 is taken and the cutaway view is shown in detail in FIG. 3C. The main radiator (in this case the ions 8) strikes the inner channel wall 27. This wall is the catalyst for most of the electrons 6 generated by the single channel 27. Finally, FIG. 3D shows the relationship between the microchannel plate 26 and the anode detector 22. This figure explicitly shows how the ions 8 colliding with the microchannel plate 26 generate the electrons 6 detected by the single anode detector 22. In FIG. 3A, when the signal information is received by the electronic component 24 at the anode detector 22, it is digitized. Digitization occurs at relatively high speeds, typically on the order of one or two nanoseconds. This is why the transient digitizer 24 is also called a "high-speed digitizer". Despite having the side of a single channel (anode detector 22), a major advantage of transient digitizer 24 is that it can handle multiple ion hits of anode detector 22. As a result, the dynamic range is significantly larger. Usually, this range can be represented by 8 bits. ⁸ = 256-step increments are possible. To understand the advantages of the present invention, it is helpful to first look at the low temporal resolution example of the prior art transient digitizer 24. Assume that two ions hit the microchannel plate 26 and were detected by the single anodic detector 22 of the mass spectrometer 20 shown in FIG. 3A. FIG. 1B shows these two hits 17 very close in time. A disadvantage of the prior art transient digitizer 24 is that it does not distinguish between these close hits, for reasons such as pulse broadening in the microchannel plate and signal processing electronics. A single anode detector 22 produces only a single electrical pulse and incorrectly indicates a single hit. In other words, the temporal resolution of the transient digitizer 24 is worse than the pulse width generated by the detector and associated electronics 24. Therefore, a feature of the digitizer 24 is that the time resolution is average. Further, the S / N ratio and signal averaging characteristics of the digitizer 24 are also generally within the ordinary skill in the art. The detection limit improves with the square root of the average number. In addition, it is very susceptible to baseline noise and drift limitations. Although the baseline noise appears small in FIG. 1A, the disturbance 18 is evident in the waveform 10. FIG. 2A shows a second type of graphic output of the data acquisition device used for the description. This device is referred to in the industry as a time-to-digital converter (hereinafter referred to as TDC or TDC converter). TDC has both advantages and disadvantages over the transient digitizer described above. However, the most significant disadvantage is that the useful output depends on the measurement signal being repeated over a relatively long period of time. This is so that the TDC can perform signal averaging to generate a meaningful output waveform. In other words, the dynamic range for a short period (eg, a single shot) is very limited. Surprisingly, however, not only for long-term signal averaging, but also when the signal is relatively small and repetitive and the TDC receives a large number of hits, the dynamic range of the TDC is generally better than a transient digitizer. ing. Waveform 40 must be considered as the result of signal averaging processed over a relatively long period of time. It should be noted that the waveform 40 is smooth between the displayed pulses. This is because, unlike the transient digitizer 24, it is essentially not subject to baseline noise. The most salient feature of TDC is to determine when a pulse occurs. This operation is similar to the function of the high-speed A / D converter. A TDC without summation provides only a series of pulse information. However, it is useful to add this information in a signal averaging calculator and use it to detect the total number of pulses generated per unit time, similar to a counter. As with the transient digitizer 24, each time an ion strikes the microchannel plate 26 and the anode 22, an electrical pulse is generated. A more accurate description of the signal averaging function of the TDC will allow a better understanding of the advantages of the present invention. FIG. 2B illustrates hits detected by the plate and anode detector during one cycle of the repetitive signal. From this graph, it can be seen that one hit was detected by the anode at relative time position 1 and two hits were detected at time position 3. FIG. 2C shows a graph of the same repetitive signal in a subsequent period. In cycles 1 and 2, one hit is shown. Finally, FIG. 2D shows the accumulated signal average power of the TDC. The TDC does not record the two hits that occurred in period 3. As will be described in more detail below, FIG. 2E shows the output of an exemplary embodiment of the present invention. Prominent is the display of two hits in period 3, which cannot be displayed by prior art TDC. Thus, FIG. 2E illustrates one of the important advantages of the present invention. Another factor affecting the time resolution of TDC is immobility time. Dead time is an important factor in the bad single shot dynamic range of TDC, typically in the 10 nanosecond range. This is because the TDC cannot handle multiple simultaneous hits. Thus, as shown in FIGS. 2B-D, simultaneous or near hits are counted and registered as one. Further, in some cases, nearly simultaneous hits may be recorded as an average, that is, an intermediate time between two adjacent hits. Although the single shot dynamic range is not good, TDC has several advantages over the transient digitizer 20. In particular, TDC is robust against noise or baseline drift. TDC actually has an excellent S / N ratio. This is because one threshold must be reached to register an ion hit. Further, compared to the transient digitizer 20, the production of the TDC electronic circuit can be performed at a lower cost. Most importantly, the signal averaging characteristics of the TDC are excellent and are improved in proportion to the square root of the detection limit for a certain time. The block diagram of the TDC electronics is the same as that of the transient digitizer, and is also shown in FIG. 3A. FIG. 3A shows a time-of-flight mass spectrometer 20 in which ions are injected from an injection port 34. A pulsed reflective electrode plate 36 at the end of the chamber 30 closest to the injection port 34 accelerates ions toward the opposite end of the flight tube 32. The movement of the ions is manipulated by the field definition electrode 38. The microchannel plate 26 and the single anode detector 22 are then used to detect ion bombardment for mass spectrometry applications. Ion hits typically generate about one million electrons, which are detected by TDC. The TDC is shown as an electronic component 24 connected to the anode 22. Electronic component 24 responds to an electrical pulse indicating an ion hit. Other molecular impact detection circuits use multiple detectors, such as those used in some imaging systems. However, while the imaging system is only designed to provide location information, the present invention provides time versus information. Therefore, building a multipolar ion detection system according to the present invention improves data acquisition of fast transient signals. To further illustrate the prior art, and as another example of distinguishing the prior art from the present invention, FIGS. 4 and 5 both illustrate, in block diagram form, the operation of a transient digitizer, TDC and image system. I have. Specifically, FIG. 4 shows a flight path 50 for ions in a transient digitizer or TDC. The ions collide with the microchannel plate 26, and the electrons generated by the impact are sent to a single anode detector 22, where the information is recorded and processed by the electronic component 24. FIG. 5 shows that the detector 56 of the imaging system is arranged such that the photons illustrated by paths 52 and 54 are detected by the associated electronics 58 based on position. Given the advantages and disadvantages inherent in each data acquisition device, it may be advantageous to combine and improve the best quality of each device. In particular, the following flight time data acquisition device is desired. In other words, it has a wide dynamic range, improved time resolution, low noise, better signal averaging characteristics than a transient digitizer or a time-to-digital converter, and a single-shot scale waveform output. is there. It would also be advantageous to have a multi-pole time-to-digital converter so that multiple hits could be processed to minimize the effects of dead time. Object and Summary of the Invention It is an object of the present invention to provide a data acquisition method and apparatus with a large dynamic range. Another object is to provide a data acquisition method and apparatus with improved temporal resolution. Another object is to provide a data acquisition method and apparatus with an excellent S / N ratio. Another object is to provide a data acquisition method and apparatus with excellent signal averaging quality. Another object is to provide a data acquisition method and apparatus that uses a multipolar ion detection system that can typically handle simultaneous ion collisions or hits. Another object is to provide a single shot dynamic range time-to-digital converter with a scaled waveform output. Here, the scale waveform represents a TDC output that can indicate a plurality of values at a specific time. According to these and other objects of the invention, the advantages of the invention will become more apparent from the following description and appended claims, or may be learned by the practice of the invention. The present invention provides a data acquisition method and apparatus, and in a specific embodiment, performs time-of-flight mass spectrometry. Use a system consisting of multi-pole detectors to improve the dynamic range of TDC. By providing a plurality of anodes, it is possible to continuously detect ion collision even during the fixed time of the individual anode detector that processes hits. The data obtained from the multi-pole system is processed, and as a result, for each time frame, the total number of hits can be aggregated and a time stamp can be added to the data to create a multi-bit word. This method substantially combines all the advantages of a transient digitizer with those of a time-to-digital converter in acquiring signals from a pulse-based detector, such as a detector using a microchannel plate. According to one aspect of the invention, a plurality of anodes are provided at one end of the flight tube to receive ions accelerated by a pulse generator / reflection electrode or electrode at another end of the flight tube. The plurality of anodes can be arranged in any geometry as long as they are arranged to receive electrical pulses from the microchannel plate and each anode is connected to a different threshold detector. Generally, the anodes are physically located parallel to each other. According to another aspect, by including multiple anodes, the TDCs of the present invention can function in parallel. This allows the other anode to be actively receiving and processing other ion hits while one hit is being processed by one detector. In another aspect of the invention, the photon detection device comprises a plurality of anodes. In this manner, the present invention can be used for acquiring visual data, such as detection of a fluorescence decay rate. Thus, when using the term "ion hit", "photon hit" may be used instead. In another aspect of the invention, the system can compensate for the loss of coincidence resulting from multiple ions occurring at the process detector during dead times. Use empirical research and statistical analysis to compensate and extend the first order dynamic range of the invention. These and other objects, features, advantages and other aspects of the present invention will be more clearly understood by those skilled in the art from the following detailed description with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE FIGURES FIG. 1A shows a typical single shot waveform from the output of a transient digitizer known in the prior art. FIG. 1B illustrates two ion hits that are relatively close in time. FIG. 2A is a diagram illustrating an output waveform after performing a long-time signal averaging process on a time-to-digital converter (TDC) known in the prior art. FIG. 2B is a diagram illustrating detection of an ion hit in the first cycle of the repetitive signal. FIG. 2C is a diagram illustrating detection of an ion hit in the second cycle of the repetitive signal. FIG. 2D is a diagram illustrating the signal averaged signals of FIGS. 2B and 2C with a prior art TDC. FIG. 2E shows the signal averaged signals of FIGS. 2B and 2C when the prior art TDC is replaced with an exemplary embodiment of the present invention. FIG. 3A is a block diagram showing the relevant elements of a time-of-flight mass spectrometer and associated electronics represented by a transient digitizer or TDC used in the prior art. FIG. 3B is a perspective cutaway view of the microchannel plate of FIG. 3A. FIG. 3C is an enlarged perspective cutaway view showing details of the single microchannel shown in FIG. 3B. FIG. 3D shows the microchannel plate in relation to a single anode detector and shows details of how ion collisions in the microchannel plate are detected by the anode detector. FIG. 4 is a functional block diagram showing a single anode detector used in the prior art. FIG. 5 is a functional block diagram of a position detector having a plurality of detectors used in the prior art. FIG. 6 is a functional block diagram showing a preferred embodiment of the multipolar TDC of the present invention. FIG. 7 is a block diagram of a mass spectrometer coupled to a multipole TDC made in accordance with the principles of the present invention to enhance the primary dynamic range of the data acquisition device. FIG. 8 is a block diagram showing components of the related electronic component of FIG. FIG. 9A is a diagram showing a preferred arrangement of detectors used in the present invention. FIG. 9B is a diagram showing another arrangement of detectors used in the present invention. FIG. 10 is a diagram showing still another arrangement of the detector used in the present invention, and is a diagram showing the relationship between the size of the detector and the impact area of the molecule to be detected. FIG. 11 is a diagram illustrating the extended primary dynamic range of the present invention when compared to the dynamic range achieved by prior art TDC, without scaling. FIG. 12 is a flowchart illustrating a preferred method according to the present invention for detecting a molecule that hits a detector and produces a multi-bit word representing the total number of hits occurring within a predetermined time frame. FIG. 13 is a diagram illustrating additional steps to the method of FIG. 12 in a preferred embodiment of the present invention. FIG. 14 is a diagram illustrating additional steps to the method of FIG. 13 in a preferred embodiment of the present invention. FIG. 15 is a diagram illustrating additional steps to the method of FIG. 14 in a preferred embodiment of the present invention. FIG. 16 is a diagram illustrating additional steps to the method of FIG. 15 in a preferred embodiment of the present invention. FIG. 17 is a diagram illustrating additional steps to the method of FIG. 16 in a preferred embodiment of the present invention. FIG. 18 is a diagram illustrating additional steps to the method of FIG. 17 in a preferred embodiment of the present invention. FIG. 19 is a diagram showing a circuit of a preferred embodiment of the present invention described below. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION Reference is made below to the drawings. In these drawings, Various elements of one preferred embodiment of the present invention are numbered, Preferred embodiments of the present invention have been described so that those skilled in the art can make and use the present invention. The present invention This is shown in the block diagram of FIG. One of the differences between the prior art shown in FIGS. 4 and 5 and this preferred embodiment is that It is easy to see that a plurality of anodes 60 were provided on the time-to-digital converter (or other similar detector for detecting other molecules such as photons) so that ion hits could be detected. Representative ions Ion path 62, Represented by 64 and 66. But, The associated electronic component 68 differs from the arrangement of FIGS. This new configuration, 3 illustrates the concept of a preferred embodiment. That is, Sum all ion hits that occur in a given time frame, It is encapsulated as an individual time frame 70. Also, As shown in ion flight paths 62 and 64, A single time frame may include multiple ion hits to the same anode 4 (via microchannel plate 26). This ion hit record is This is one of the important advantages of the present invention. this is, Many advantages of transient digitizer and TDC As explained below, This is because they can be conveniently combined into a single data acquisition system. Along with the block diagram of FIG. An apparatus enabling the present invention in this preferred embodiment is shown in FIG. One of the most notable differences between the device shown in FIG. 3A and the preferred embodiment shown in FIG. The point is that a plurality of anodes 80 are used instead of the single anode detector 22. By providing a plurality of anodes 80, During the dead time of the individual anode detector 80, which is processing a hit and cannot detect the next hit, The system can continue to detect ion collisions. Data from the plurality of anodes 80 is processed by associated electronic components 82, as a result, In each time frame, Aggregate the total number of hits, then associate a timestamp (or another way to group information over time) with the data, A multi-bit word can be created that is the sum of all ion collisions in a one-hour period. FIG. It shows a functional diagram of a preferred example of the related electronic component 82 (see also FIG. 7), here, A plurality of threshold detection circuits 84 are associated with the plurality of anodes 80. In this preferred embodiment, Separate threshold detector circuits 84 are provided for each anode 80. Threshold detector circuit 84 is only one preferred example of threshold detector means, If this circuit is not provided, it is designed to eliminate electrical noise that may indicate an ion hit that does not actually occur to the anode 80. Therefore, The threshold detector circuit 84 Only when the impact ions generate a large enough electric shock, Set to indicate that an ion hit has occurred. Therefore, The pulse of electrons generated by the ion hit is smaller than the size of each individual anode 80, It is expected that the diameter will be large. When the ion bombardment overlaps such that the ion energy is diffused to the plurality of anodes 80, Only a single anode 80 can be distinguished so that impact can be registered to that anode. One of the important differences between the prior art and the present invention is that In a preferred embodiment, to create one multiple bit word, The point is that the total number of ion collisions is obtained within a time frame. Multi-bit words are Each time period, Represents a summary of all hits that occur in a slice or frame. More advantageously, Using a dynamic range modification technique according to another aspect of the invention described below, The dynamic range of the multiple anode TDC can be further expanded. A TDC 82 that can extract data from a plurality of anodes 80 Provide a multi-bit word that represents the total number of hits found. this is, A pulse counter 86 and a sum register, That is, This is performed by incorporating the first memory register 88. The pulse detector 86 of the preferred embodiment comprises: It is known to those skilled in the art as a single shot detector. further, The first memory register 88 is a memory register or a memory buffer, It is organized as a binary tree. This binary tree allows you to easily change the stored values, An output can be generated that represents the sum of all detected ion hits. The function of the pulse counter 86 is The sum register 88 sends a pulse interpreted as an additional ion hit. This additional ion hit It is added to the stored value using any of several methods well known in the art. But, This first memory register 88 Used only to store the number of current electrical pulses received in the current time frame. When the time frame determined by the clock (not shown in FIG. 8) in the TDC converter ends, The value stored in the first memory register 88 is It is processed in one of the following three ways. 1) Sent to a second memory register or summation register 90. This register The single summation of the pulses detected in a plurality of time frames up to that time is stored in the memory. 2) Used to generate a single multi-bit word 92 as output. 3) Directly sent to large memory 96. This function will be described later. If the multi-bit word 92 is stored in the second memory register 90 or the memory 96, The time stamp is To create a single shot output waveform like the waveform shown in FIG. 2E, Usually associated with data. The time stamp is The sum of the pulse counts is related to the sum of all other pulse counts, It defines when it was recorded. Before continuing, The time stamp is It will be described that this is only one method of storing data that enables sequential access of data. For example, Linked lists, Memory stack, Other memory devices or methods used for array or data storage can be used. Due to the nature of the location in the memory device, These devices can also define a position indicating a temporal relationship with other data. That is, The data recording time is implicitly indicated by the order in which the data was stored in memory. Therefore, If all relative time positions are required, It is sufficient to store the data so that the data can be recalled in the order in which the data was created. If you store it like this, To overlay a time scale that increases in units of time representing the time the data was stored, Data can be recalled. Continuing with the description of memory 96 and memory registers 88 and 90, The second memory register 90 can also accumulate the single addition sum. This sum is It is the sum of at least two multi-bit words generated by the first memory register 88. If you use timestamps, The time stamp remains associated with the value of the second memory register 90. This association is In the preferred embodiment, the time stamp is passed to memory 96 and the value is recalled as a single output 94 or continues until passed. Unlike the first and second memory registers 88 and 90, Memory 96 is a larger dynamic memory space, A plurality of multi-bit words generated by either the first or second memory registers 88 and 90 can be stored. The memory 96 Memory can be called sequentially, Any memory storage device. this is, Rather than having to store data sequentially, According to the timestamp associated with the stored data This means that the data can be recalled in the order stored. Recalling the data in the order in which it was stored It may implicitly indicate that the recall is based on data storage order. For example, To create a sequence or linked list understood by those skilled in the art, A memory 96 can be used. But, Using random access memory, The data can be recalled in the order stored. Those skilled in the art If the memory 96 is a random access, It can also be seen that the first memory register 88 and the second memory register 90 are capable of specific memory addresses in the memory 96. It is important to recall the data in the order in which it was stored. this is, This time schedule data is displayed on a display device, etc. This is because it can be created as an output. Therefore, The data stored in the memory 96 is It is clear that the content is recalled at output 98 to produce the single shot waveform shown in FIG. 2E. Nevertheless, Sequential recall can be performed in various ways using various devices and various methods, It is important to understand that this example does not limit the invention. Another idea implied is: It is to be understood that the memory 96 need not be a random access memory. Since the data must be recallable sequentially, Linear access memory means can also be used. For example, A bubble memory can also be used as the memory 96. A typical single shot output waveform of the output generated by the present invention is: This is shown in FIG. 2E. Unlike prior art, The TDC of the preferred embodiment of the present invention is: Almost simultaneous ion hits in time period 3 in FIG. 2B can both be registered. Therefore, The total count in time period 3 of FIG. It reflects the count of these two hits. Therefore, The preferred embodiment is Includes a more accurate TDC than the TDCs that existed in the prior art. Preferred embodiments of the invention are: It can be seen that the performance is significantly improved compared to the prior art transient digitizer. In particular, The preferred embodiment has improved dynamic range compared to TDC, When compared to the transient digitizer, The time resolution has been improved. A specific physical arrangement of the plurality of anodes 80 shown in block diagram form in FIG. To explain the configuration or direction, In the present invention, It can be seen that a plurality of anodes 80 can be arranged in any pattern. inevitably, Depending on the specific application of the multi-pole TDC converter, The arrangement of the anode is defined. In the preferred embodiment, The anodes are arranged so as not to overlap. this is, As shown in FIG. 9A, This is to make the surface area of each anode 80 exposed to ions the same. The arrangement in two rows This is a specific arrangement of the anode 80. here, The first row 100 has 31 anodes, The second row 102 has 32 rows (anodes). Column 100, 102 is To create the pattern shown in FIG. 9B, It can be arranged to be offset by about half the length of a single anode 80. Also, Column 100, 102 is Place so that there is no offset, Therefore, It can also be arranged so as to form a pattern as shown in FIG. 9A. Factors that must be considered as factors in determining the specific arrangement of the anode 80 include the following. The size of the individual anode, The total area where the ions bombard and therefore must be covered with the anode, The shape of the area where the ions can collide (such as arranging the anodes in a row or circular pattern), Spot size (area of the anode affected by ion bombardment on the microchannel plate), Physical constraints of the circuit associated with the anode, And the outline of the ion beam. What is clear from this incomplete list is that The application of the multipolar TDC of the selection example is to those skilled in the art. It clearly requires a particular geometry to be chosen for the placement of the anode (implicitly implies a microchannel plate that is actually subject to ion bombardment). FIG. In that ions (and photons) create a measurable impact area (spot size) on the microchannel plate and the anode below it (wherever it is placed in relation to the microchannel plate) The size of the anode 80 is also shown to be relevant to the present invention. Also, The pattern of the anode 80 is Instead of the columns in FIGS. 9A and 9B, Note also that it is configured as a square. this is, The idea is that the anode can be configured in a pattern that best suits the particular application. The area of impact of the detected ions (defined as the pulse of electrons generated by the impact of the ions on the microchannel plate) is This is indicated by a circle 81. If the size of the anode 80 (or associated detector) is large compared to the impact area 81 of the molecule impacting the anode, There is less chance that a single molecule will cause multiple anodes 80 to generate an electrical signal representative of the colliding molecule. But, If the size of the anode 80 is close to the measurable shock area as shown here, The likelihood of the plurality of anodes 80 detecting a hit increases. The very obvious thing is that The impact size 81 is that it can cover up to nine anode 80 parts. But, The amount of energy supplied to each anode 80 varies significantly. After the energy threshold level is reached, the impact will be a hit, The sensitivity of the device can be adjusted appropriately. Also, The anode detects an ion hit after a certain percentage of the anode falls within the impact zone 81, It can also be considered. Before further describing the advantages of the present invention, It is helpful to look at FIG. this is, Dynamic range of prior art devices; The present invention which does not use the dynamic range compensation technique; This is a comparison with the present invention using the technique. Therefore, From this figure, one of the main aspects of the present invention can be easily understood. In particular, By providing multiple anodes, The dynamic range and time resolution of the present invention are improved. As those skilled in the art will appreciate, The dynamic range mentioned is It refers to the relationship between the number of recorded ion hits (on the y-axis) detected by the data acquisition device and the actual number of hits (on the x-axis). But, It is helpful to see this relationship as described earlier. In particular, The dynamic range is There is no signal distortion that usually occurs at the time of large signal, In a state where the signal does not become undetectable due to noise when it is a small signal, This function measures both large signal and small signal attributes. The ideal dynamic range is It is represented by a straight line 104 drawn at an angle of 45 degrees from the origin 106 of the x and y axes. this is, 1 shows a perfect correspondence type data acquisition device capable of detecting and recording all signals including large signals and small signals. According to the empirical results shown in the graph of FIG. The dynamic range 106 of the prior art data accumulator is: Finally, it can be seen that it deviates from the ideal straight line 104. The straight line 107 is It is shown to represent the dynamic range of prior art devices that use certain compensation techniques to increase the accuracy of the measurements. Although the graph of FIG. 11 is not drawn according to the scale, 5 effectively illustrates the dynamic range enhancement achieved by the present invention. this is, This is shown by comparing the low dynamic range of straight lines 106 and 107 (early deviating from ideal straight line 104) with the high dynamic range of straight line 108. The straight line 108 Figure 3 illustrates the high dynamic range achieved by the present invention as a result of a multi-pole design. In other words, The actual number of hits is accurately reflected by the results of the present invention. this is, By using multi-pole TDC, This is because the attributes of the small signal and the large signal can be accurately measured. The straight line 109 is It is shown to represent a further improved dynamic range. this is, This can be achieved by the present invention when the system compensates for the loss of coincidence. the system, By using some kind of compensation means, the loss of coincidence can be compensated. In a preferred embodiment of the invention, Use statistical analysis or past empirical results as a means of compensation, It provides a compensation factor (as understood by those skilled in the art) that delays departure from the ideal straight line 104. To extend the dynamic range of the present invention using compensation coefficients as described above, In order to generate a compensation factor and produce a corrected (compensated) output, Multi-pole TDC converters need to process the actual data measurements recorded in all parts of the memory. Data processing is The nature of the calculations to be performed, Depending on factors such as the speed of TDC, Microcontroller, It can be executed by providing a microprocessor or hard-wired logic. These data processing devices Cross-reference with statistical data stored in memory, etc. Use actual data. For example, If you use a look-up table to cross-reference the actual data with previous statistically calculated or empirical measured numbers for the ion hits of the incomplete detection, The calculations performed by the processing device tend to be limited to calculations that add the compensation coefficient to the actual data relatively simply. But, Even if the processing unit is only required for minimal calculations, May require more important functions. For example, If you want to make statistical calculations based on empirical results, Important operations may be required to get the output. Therefore, When practicing the present invention, Microcontroller, To determine whether to apply a microprocessor or hard-wired logic, The necessary processing method to obtain the compensation output must be determined. The present invention In other words, By measuring how much the dynamic range of the present invention has increased, Can be classified. In the understanding of those skilled in the art, The TDC converter of the present invention If you do not use dynamic range correction with compensation factors, It has been proposed to have a dynamic range equal to the number of anodes used for its construction. Therefore, The preferred embodiment of the present invention is a multi-pole TDC converter, The dynamic range has been increased by a factor of 63. However, this restriction It can be applied to any multi-pole TDC converter as appropriate. further, The coefficient of 63 is not limited, This is just an example that was implemented. Also, Note that this coefficient is also adjustable. that is, This compensation coefficient is The preferred embodiment of the present invention, both dynamic range and time resolution, This is because the improvement is made even more than the improvement by the actual number of anodes. The device of the present invention The invention has been described in detail so that those skilled in the art can make the invention. But, To benefit the most from using the present invention, As explained below, The skilled practitioner will benefit from other specific aspects of the use of the present invention. FIG. The minimum steps performed in the preferred embodiment of the present invention are: This is shown in the form of a flowchart. These minimum steps do not output TOF data, Used to generate a single multiple bit as output. This method Clearing the sum register (first memory register) 110; Detecting 112 at least one ion hit at any of the plurality of anodes; Summing all detected ion hits 114; And generating a sum (in the form of a plurality of bit words) stored in the sum register 88 as an output 118. Also, Instead of using only a predetermined time frame to determine when to start a new recording cycle, It should be noted that detection can be limited to multiple hits per anode. This process, outlined above, It can be analogous to an analog-to-digital (A / D) converter, but The difference is Instead of digitizing analog signals, The point is to generate a digital value equal to the sum of the number of ion hits in a particular time or very short time. FIG. 13 is almost the same as FIG. 12, but It has been modified by the addition step 120. Step 120 is Introduce the idea of a loop into the detection and summation process, A series or multiple multi-bit words are generated as output 122. This method It is similar to a continuous clock A / D converter that does not store outputs. FIG. Some steps are added to the flowchart of FIG. The outputs 122 of the multi-bit word are: During a plurality of loops in step 120, the sum is calculated in step 124. The second memory register 90 (FIG. 8) where the sum of step 124 is calculated, It is assumed that it has been cleared in step 124 before the summing process is started. When the total of the predetermined number of loops in step 120 is stored in the second memory register 90, At step 126, second memory register 90 outputs one multi-bit word as output 128. this is, This is the sum of all ion hits during a plurality of 120 cycles of steps. This method For example, it is useful in the following scenario. There are light sources that change dynamically, Suppose that the total number of photons emitted from this light source at a specific time of 1 microsecond is needed. If the detector is not the anode (described above), For photon detectors like arrays of avalanche photon diodes, Output 128 is one multi-bit word representing the total number of detected photons. FIG. It is similar to the modification of the steps in FIGS. That is, The additional step 130 is an iterative loop, this is, A series or a plurality of multi-bit words 132 are to be generated from the second memory register 90. here, Each multi-bit word is Output after cycle 130 has been fully executed. FIG. FIG. 16 shows an additional step set added to the steps shown in the flowchart in FIG. 15. The flowchart is In a new step 134, The plurality of multi-bit words 132 generated from the second memory register 90 of FIG. 15 are stored in memory at step 134. here, The memory pointer is incremented at step 136, Point to the next memory storage address. The cycle of step 138 is Executed each time a new multi-bit word is stored in the memory array. Data storage and memory hardware As long as they can be recalled sequentially when needed by combining them, Any combination is possible. But, There is no need to actually store the data itself sequentially. That is, They can also be stored in an array consisting of memory addresses sequentially. Also, It can also be stored in a linked list array. in this case, Individual memory addresses are resident anywhere in memory, Regardless of the storage location, they are linked to each other so as to always point to the next sequentially related data. Although the new steps outlined in the flowchart of FIG. 16 have been described as being linked to the output 132 of FIG. In the present invention shown in FIG. The output of FIG. 13 can also function as a source of multiple bit words. These multi-bit words are In step 134, the data is stored as sequentially retrievable data. Using this method, The total layer introduced in FIG. 14 becomes unnecessary. this is, Some applications may be irrelevant to the purpose of the present invention. FIG. 4 illustrates a method for summing repetitive transients. This last flowchart is It is a modification of the step of FIG. These two flowcharts When printing an additional multi-bit word to the current memory location pointed to by the memory pointer, The sum of the value stored in the current memory location and the additional multi-bit word is calculated, In that it overwrites the value stored in the current memory location. Is the same. But, In a new step 142, Determines if an out-of-memory condition exists. If the result is positive, The memory pointer is reset to the first location in memory at step 144. Data is, So that the oldest data is overwritten first It is stored so that it is overwritten from the beginning of this position. Before overwriting the memory, Note that step 146 confirms that no stop condition has been detected. The stop condition is For example, expiration of a predetermined time frame for detecting ions or photons. When a stop condition is detected, As shown in step 148, One of three steps is performed. First, Leave the data in memory, Stop recording data. The second is Data stored in memory Output to a storage device or a display device. The third option is Move to another area of memory or another storage medium and start again, Keep the old data. In summary, The present invention A method and apparatus for summing repetitive transient signals is provided. this is, This is done by improving the dynamic range and time resolution of the TDC converter. for that reason, Prepare multiple anodes and related circuits, A plurality of bits are generated that are approximately equal to the total number of detectable ion hits within a predetermined time frame. Generated as a result of ion hits on the microchannel plate, Extracting a digital pulse from the electrical signal registered by the at least one anode; This pulse is counted in a predetermined substantially equal time frame, Sum digitally. next, The present invention Generate a multi-bit word representing the total number of hits in each time frame. All or part of the individual time frame Displayed as a single shot waveform. But, By manipulating the data, Better results can be obtained than time-of-flight (TOF) data from a mass spectrometer. Also, In this method and apparatus, Data acquisition with a low S / N ratio and excellent signal averaging quality can be performed. Also, In a preferred embodiment of the invention, Also provided is a method and apparatus for data acquisition using a multipolar ion detection system that processes substantially simultaneous ion hits. Also, Also provides scale waveform output. The scale waveform is It shows a TDC output that can indicate a plurality of values at a specific time. To show more clearly how to create the circuit exactly, A circuit diagram of a preferred embodiment of the present invention is shown in FIG. To more explicitly define the labels and connections used to identify the circuit of FIG. The details will be described below. First, at the left end of FIG. Two first-in first-out (FIFO) stack queues 200, 202. this is, There is a 16-bit data input line, This is connected to the Xilinx integrated circuit 204 (IC). Xilinx IC 204 The transmission and reception with the board 0 (zero) 206 are executed. Board 0 206 includes an averaging IC 208, This is a timer digital signal processor (DSP) 210, The status LED 212 is connected. Also, There is also a host DSP 214, There is a random access memory (RAM) controller 216, An associated dynamic RAM 218 is connected to this. In the host DSP 214, Status LED 220, There is also an IDE bus interface 222 and a GPIB bus interface 224. Boards 1-15 226 each It has another Xilinx IC 228 with an associated DRAM 230. Xilinx IC 228 communicates with digital signal processing array 232, This arrangement is provided with a status LED 234. Also, There is also a logic gate 236, This controls input and output to other components on boards 1-15 226 and board 0 206. The above example is It merely describes an application of the principles of the present invention. By those skilled in the art, Without departing from the spirit and scope of the invention, Several variations and alternative arrangements are possible. The claims are It is intended to include such modifications and arrangements.

────────────────────────────────────────────────── ─── Continuation of front page    (31) Priority claim number 08 / 818,376 (32) Priority date March 14, 1997 (March 14, 1997) (33) Priority country United States (US) (81) Designated countries EP (AT, BE, CH, DE, DK, ES, FI, FR, GB, GR, IE, IT, L U, MC, NL, PT, SE), OA (BF, BJ, CF) , CG, CI, CM, GA, GN, ML, MR, NE, SN, TD, TG), AP (GH, KE, LS, MW, S D, SZ, UG, ZW), EA (AM, AZ, BY, KG) , KZ, MD, RU, TJ, TM), AL, AM, AT , AU, AZ, BA, BB, BG, BR, BY, CA, CH, CN, CU, CZ, DE, DK, EE, ES, F I, GB, GE, GH, HU, ID, IL, IS, JP , KE, KG, KP, KR, KZ, LC, LK, LR, LS, LT, LU, LV, MD, MG, MK, MN, M W, MX, NO, NZ, PL, PT, RO, RU, SD , SE, SG, SI, SK, SL, TJ, TM, TR, TT, UA, UG, US, UZ, VN, YU, ZW

Claims (1)

[Claims]   1. Extend the dynamic range and increase the time resolution to improve the time-related properties of molecular streams A time-to-digital (TDC) converter for more accurate discrimination,   First detector means for detecting the impact of a surface molecular stream, wherein the first Generating a first electrical signal from the detector means of   A second detector means for detecting the impact of the surface molecular stream; Generating a second electrical signal from the detector means of   At least one further detector means for detecting the impact of the surface molecular stream; At least one other electrical signal from at least one further detector means due to impact Produces   Receiving the first, the second and the at least one other electrical signal Processing the first electrical signal, the second electrical signal and at least one other electrical signal at There is no time-related distortion that occurs in large signals, and it occurs in small signals. Time-related characteristics of molecular streams without being undetectable by noise, which is a time-related characteristic A TDC converter.   2. 2. The TDC converter according to claim 1, wherein the first detector means, the second detector means, The detector means and at least one other detector means are adapted to impinge the molecular stream on the surface. A member of a plurality of detector means for detecting strikes, TDC converter for generating a first plurality of electrical signals from detector means Place.   3. 3. The TDC converter according to claim 2, wherein each of the plurality of detector means is provided. The molecular stream that impacts it is characterized as a continuous transient signal TDC conversion device.   4. 4. The TDC converter according to claim 3, wherein each of the plurality of detector means comprises:   A surface molecular stream is received and a first plurality of currents are responsive to the molecular stream. A microchannel plate arranged to generate an air signal;   Receiving and processing the first electrical signal to generate a first processed electrical signal; A first anode electrically connected to the microchannel plate;   Receiving and processing the second electrical signal to produce a second processed electrical signal; A second anode electrically connected to the microchannel plate;   Receiving and processing at least one other electrical signal, wherein the first processed at least Also electrically connected to the microchannel plate to generate one other electrical signal. At least one other anode connected   A first processed electrical signal, a second processed electrical signal and at least one Characterized in that the other processed electrical signals represent the time-related properties of the molecular stream TDC converter.   5. The TDC converter according to claim 4, wherein the first anode, the second anode and And at least one other anode generate a second plurality of processed electrical signals. A plurality of anode members for processing a first plurality of electrical signals. TDC converter.   6. 6. The TDC converter according to claim 5, wherein the molecular stream comprises a plurality of streams. Select from a molecular group consisting of ions and photons that collide with the detector means A TDC converter characterized by the above-mentioned.   7. 7. The TDC converter according to claim 6, wherein the first electric signal is a micro signal. First clear surface of the surface generated at the point of impact from the channel plate and usually aligned with the point of impact A TDC converter characterized by being received by a pole.   8. 6. The TDC converter according to claim 5, wherein the TDC converter processes the first plurality of electric signals. The means for managing includes a first plurality of each of the plurality of powers exceeding a selectable threshold energy level. A gas signal can be generated from the plurality of anodes as a second plurality of processed electrical signals. TDC converter further comprising a plurality of threshold detectors Place.   9. 9. The TDC converter according to claim 8, wherein the time-related characteristic is determined. Means for processing the first plurality of electrical signals for generating a sumable pulsed electrical signal A plurality of threshold detectors for processing the second plurality of processed electrical signals TDC converter further comprising counting means electrically connected to the means. Place.   10. The TDC converter according to claim 9, wherein a time-related characteristic is determined. Means for processing the first plurality of electrical signals for generating within a selectable time frame Sum the total number of pulsed electrical signals to get a small number representing the total number of pulsed electrical signals at the output. A first means coupled to a counting means for generating at least one multi-bit digital word; A TDC converter further comprising a memory register.   11. The TDC converter according to claim 10, wherein a time-related characteristic is determined. Means for processing the first plurality of electrical signals for generating within the selectable time frame. Receiving and aggregating the at least one multi-bit digital word; , To provide an output of at least one second multi-bit digital word, A second memory register electrically connected to the output of the first memory register; And a TDC converter.   12. The TDC converter according to claim 10, wherein a time-related characteristic is determined. Means for processing the first plurality of electrical signals for generating within the selectable time frame. Receiving and aggregating the at least one first multi-bit digital word For this purpose, a memory electrically connected to the first memory register at the output point is provided. And a TDC converter.   13. 12. The TDC converter according to claim 11, wherein a time-related characteristic is determined. Means for processing the first plurality of electrical signals for generating within the selectable time frame. Receiving and processing a plurality of at least one second multi-bit digital word For this purpose, a memory electrically connected to the second memory register at the output point is provided. And a TDC converter.   14． The TDC converter according to claim 11, wherein the TDC is a selectable operation. According to the method, the counting means, the first memory register, the second memory register and And a control means for adjusting the operation of the memory. Conversion device.   15. The TDC converter according to claim 10, wherein a time-related characteristic is determined. The means for processing the first plurality of electrical signals comprises at least one first plurality of electrical signals. By changing the bit digital word by the compensation coefficient representing the number of compensation hits, Compensation means for compensating for multiple signal hits on unexposed microchannel plates A TDC converter, further comprising:   16. 16. The TDC converter according to claim 15, wherein a time-related characteristic is determined. Means for processing the first plurality of electrical signals for generating within the selectable time frame. Lookaer electrically connected to store a value representing the total number of pulsed electrical signals And a stored table, wherein each stored value has at least one first multi-bit data. TDC characterized in that a compensation coefficient to be added to the digital word is associated Conversion device.   17． 16. The TDC converter according to claim 15, wherein a time-related characteristic is determined. Means for processing the first plurality of electrical signals in order to generate statistical or empirical data. And adding to at least one first multi-bit digital word A TDC converter for calculating a number.   18. The TDC converter according to claim 11, wherein the memory is selectable. A plurality of at least one first multi-bit digital words generated within a time frame By recalling the timestamp associated with each of the A TDC converter characterized by sequentially recalling data that has been stored.   19. The TDC converter according to claim 11, wherein the memory is selectable. A plurality of at least one first multi-bit digital word generated within a time frame Are recalled in the order stored in the memory so that the stored data is Recalls data and implicitly adds a time stamp to data when stored TDC converter.   20. 2. The TDC converter according to claim 1, wherein the TDC is the molecular string. TD further comprising display means for graphically displaying the characteristics of the ream. C converter.   21. 21. The TDC converter according to claim 20, wherein the molecular stream is Time-related characteristics are displayed as a single shot scale waveform. TDC conversion device.   22. The TDC converter according to claim 5, wherein the plurality of anodes are overlapped. A TDC converter characterized in that the TDC converters are physically arranged so as not to be disconnected.   23. 23. The TDC converter according to claim 22, wherein the plurality of anodes are usually less. TD characterized by being arranged in at least two rows and adjacent edges of a plurality of anodes C converter.   24. 24. The TDC converter according to claim 23, wherein a maximum of the plurality of detectors is provided. At least two rows so that three adjacent edges coincide at any point on the edge A TDC converter characterized in that the surface is usually offset.   25. The TDC converter according to claim 8, wherein each of the plurality of anodes is Enlarge the surface and selectable threshold energy levels for multiple threshold detectors Bell states that only one of the multiple threshold detector means is pulsed by a single molecular collision. A TDC converter having a level at which an air signal is generated.   26. 3. The TDC converter according to claim 2, wherein the plurality of detector means are positive. At least one of a detector consisting of a pole, an electron and an avalanche photon diode A TDC converter, wherein the TDC converter is selected from two groups.   27. The TDC converter according to claim 2, wherein the dynamic range of the TDC converter is The box usually features an increase by a factor equal to the total number of detector means. TDC conversion device.   28. Extend the dynamic range of time-to-digital (TDC) converters and increase time resolution Enhancement method to more accurately determine the time-related properties of a molecular stream A plurality of detector means electrically coupled to the TDC;   1) detecting the impact of the molecular stream on the surface of the plurality of detector means; ,   2) as a result of the detection of the molecular stream, a first plurality of Generating an electrical signal;   3) receiving a first plurality of electrical signals from the plurality of detector means at the TDC; And   4) Normally, there is no distortion, which is a time-related characteristic that occurs in a large signal. Is not detected by noise, which is a time-related characteristic of small signals, Processing a first plurality of electrical signals within the TDC to determine a time-related characteristic of the stream Performing the steps of:   29. 29. The method of claim 28, wherein the surface of the plurality of detector means has molecular molecules. The step of detecting the impact of the trim is   1) Set up a microchannel plate to receive the molecular stream on the surface Placing,   2) generating a first plurality of electrical signals in response to the molecular stream; ,   3) A stage having a plurality of anodes electrically connected to a microchannel plate. And   4) First multiple electrical signals from the microchannel plate to multiple anodes Sending,   5) A second plurality of processed electrical signals representing a time-related property of the molecular stream. Processing the first plurality of electrical signals to generate A method characterized by the following.   30. 29. The method according to claim 28, wherein the impact of the molecular stream is detected. Detecting the impact of ions or photons on the plurality of detector means. The method further comprising:   31. 30. The method of claim 29, further comprising generating a second plurality of processed signals. Processing the first plurality of electrical signals to produce   1) Process at least one electrical signal, determine its characteristics, and apply Providing means comprising pneumatically coupled threshold detector means;   2) less than a threshold detector means that exceeds the selectable threshold energy level Sending at least one second electrical signal. Method.   32. 32. The method according to claim 31, wherein the second step determines the time-related characteristic. The step of providing a means for processing a plurality of electric signals includes:   1) providing counting means electrically connected to the threshold detector;   2) receiving a second plurality of electrical signals exceeding a selectable threshold energy level; The step of removing,   3) generating a digital electric signal. Method.   33. 33. The method according to claim 32, wherein a second step for determining a time-related characteristic is performed. The step of providing a means for processing a plurality of electric signals includes:   1) A step having a first memory register electrically connected to the counting means. And   2) receiving a digital electrical signal by the first memory register; ,   3) calculating a first sum of the plurality of digital electrical signals generated within the selectable time frame; Generating as output.   34. 34. The method of claim 33, wherein the plurality of pulsed electrical signals are summed. The steps to generate as output are   1) Clearing the first memory register before data is stored When,   2) applying a plurality of electrical signals to a first memory register to generate a first sum; Summing to   3) generating a first sum, a multi-bit digital word, as an output; The method further comprising:   35. 35. The method of claim 34, which is a multi-bit digital word. Producing a first sum as an output comprises a plurality of multi-bit digital words. Repeating steps 1) to 3) to provide as output The method further comprising:   36. 34. The method according to claim 33, wherein the second step determines the time-related characteristic. The step of providing a means for processing a plurality of electric signals includes:   1) a second memory register electrically connected to the first memory register; Preparing,   2) Multiple outputs of the first memory register in the second memory register Receiving as a multi-bit digital word of   3) From the first memory register generated over multiple selectable time frames A second sum, which is the sum of the multiple multi-bit digital words of Generating as an output from a register. Law.   37. 37. The method according to claim 36, wherein the second sum is generated as an output. Step includes step 2) to generate a plurality of second sums as output. Repeating step 3).   38. 38. The method of claim 37, wherein providing a plurality of second sums. The top   1) Providing a memory electrically coupled to the output of the second memory register Steps and   2) receiving the output of the second memory register in memory;   3) storing the output at a memory storage address;   4) The next available memory storage address is available to store the data Increasing the memory pointer in memory to And the method characterized by the above.   39. 36. The method according to claim 35, wherein a second step for determining a time-related characteristic is performed. The step of providing a means for processing a plurality of electric signals includes:   1) having a third memory electrically connected to the output of the first memory register; Steps   2) receiving the output of the second memory register in memory;   3) A switch for storing the output of the first memory register at a storage address of the memory. Tep,   4) The next available memory storage address can be used to store data Increasing the memory pointer in memory to allow A method comprising:   40. 40. The method of claim 39, comprising providing a memory, By providing a means for recalling data in the order in which the data was stored, Further comprising providing a memory that can be used for sequential recall. how to.   41. 41. The method of claim 40, wherein the data is recalled sequentially. The step of providing memory with linear or random accessible memory. The method further comprising the step of providing.   42. 41. The method of claim 40, wherein a plurality of multi-bit digital words. Steps 1) to 3) of claim 35 are repeated to provide The step of returning is based on the timing determined when the particular multi-bit digital word was generated. Associating a time stamp with each of a plurality of multi-bit digital words The method further comprising:   43. 43. The method of claim 42, wherein providing memory comprises: Time stamps associated with each of multiple multi-bit digital words Therefore, by recalling the stored data, the data can be sequentially recalled. The method further comprising providing a memory.   44. 39. The method of claim 38, wherein the output of the second memory register is The step of storing in memory is:   1) Determine whether an out-of-memory condition has occurred and, if so, Resetting the pointer to the beginning of memory;   2) Determine whether a stop condition has occurred, and if so, step 3) If not, repeat steps 2) to 4) of claim 38. Returning step,   3) Determine which of the at least three types of stop conditions has occurred, and Generating a response.   45. The method of claim 44, wherein at least three stop conditions are included. Determining if the type of the event has occurred, and generating an appropriate response,   1) ending the data storage;   2) sending the memory to a second memory register or display;   3) Claim the memory means by moving the memory pointer to the new memory means. One of the steps of repeatedly executing step 2) to step 4) of 38 A method, further comprising:   46. 34. The method of claim 33, wherein a plurality of the sums are generated to generate a first sum. Summing the digital electrical signals of the first signal To compensate for the coincidence loss by increasing the first sum by a compensation factor representing The method further comprising the step of:   47. 47. The method of claim 46, wherein the first signal is detected. Compensating for loss of coincidence by increasing the first sum by the compensation factor representing the strike The step of looking up stores a value representative of the impact of the detected first signal. Further comprising using a map table, wherein each value is added to the first sum. Corresponding compensation coefficients are associated.