JPS58187885A - Radiation measuring apparatus - Google Patents

Abstract

PURPOSE:To invariably keep the gas gain of a radiation detector constant by correcting a bias voltage of the gas ionization amplifying type radiation detector with an average ionization current. CONSTITUTION:A gas gain G of a gas ionization amplifying type radiation detector PC is given by the formula 1 [(a), (b) and (k) represent constants, V a bias voltage of the detector PC and (i) an averaging ionization current]. An averaging circuit D forms an averaging current (i) from an ionization current generated from the detector PC to be fed to a bias voltage generator B. Then, a bias voltage generator B controls the bias voltage so as to give V=V0+ki/b (V0 represents voltage when the ionization current of the detector PC is zero) based on current (i). As a result, the gas gain G becomes as given by the formula 2 to be controlled to a fixed value. Thus, the gas gain of the detector PC can be invariably kept constant.

Description

[Detailed description of the invention] The present invention relates to a gas ionization amplification type radiation cotton d↑ measuring device.

2. Description of the Related Art Radiation measurement devices that use a gas ionization amplification type radiation detector to measure incident X-rays are known. FIG. 1 is a block diagram showing the basic configuration of the measuring device. The basic configuration and problems of a radiation measuring device using the gas ionization amplification type radiation detector will be briefly described with reference to this drawing.

A bias voltage ■ is applied from a bias voltage fjB to the anode electrode of the gas ionization amplification type radiation detector PC. By changing this bias voltage (2), a proportional amplification region is set so that an electrical pulse signal proportional to the incident X-ray energy is obtained. The output pulse signal of the gas ionization amplification type radiation detector PC, which is operated in the proportional amplification region I, is amplified by a preamplifier, and its output is connected to a wave A discriminator.

The migrating bird discriminator PHA has a comparator with a lower limit comparison voltage and a comparator with an upper limit comparison voltage, and outputs only pulses having a wave Ai (voltage) between them so that they can be measured. By counting these pulses, the intensity of X-rays with a predetermined energy in the incident X-rays can be determined.

I) The device described above is constructed on the assumption that the gas gain of the gas ionization amplification type radiation detector PC and the gain of the amplification system such as the preamplifier PA are constant; If the gas gain of the radiation detector PC and the gain of the preamplifier PA etc. are not constant regardless of the energy of the incident X-rays or changes in the intensity of the X-rays, accurate measurements will not be possible.

However, the gas gain of the gas ionization amplification type radiation detector PC is the γ node A of the gas ionization amplification type radiation detector PC.
Even if the physical shape and arrangement, such as the bias voltage (2) applied to the electrode, the type of gas filled in, the gas pressure, and the size of the anode and cathode are kept unchanged, they change due to the following factors.

That is, it changes due to changes in the intensity of the incident X-rays and changes in the energy of the incident X-rays, and the amount of change also differs depending on the magnitude of the gas gain.

Proposals have been made to perform automatic correction by focusing on this change factor.
No device has been realized that can apparently eliminate fluctuations in gas gain.

In the gas ionization amplification type radiation detector PC, the inventor of the present invention is ionized by the gas gain and the incident X-ray, which changes due to changes in the intensity of the incident X-ray and the energy of the spectrum.
Gas ionization amplification type radiation detector PC as a result of gas amplification
It was discovered that there is a certain relationship between the average ionization current of the pulse current flowing from the γ node A to the cathode K.

FIG. 2 is a graph showing the average ionization current i of the gas ionization amplification type radiation detector PC and the pulse peak value of the detection pulse signal corresponding to the average ionization current i when X-rays of constant energy are incident.

The Y-axis shows the logarithm of the peak value P, and the X-axis shows the average type #ll torrent i of the gas ionization amplification type radiation detector PC.

This graph measures the wave height values for several bias voltages, extrapolates those data to the point where the ionizing current is zero, that is, the point where there is no incident
■) It is normalized and graphed so that it becomes.

FIG. 2 is a graph showing measurement data when a spectrum of CrKα is incident on a gas ionization amplification type radiation detector PC mounted on a cylinder sealed with Xe gas. The bias voltage of the gas ionization amplification type radiation detection WPC is set to 1300.
The relationship between the ionization current and the pulse peak value when the X-ray intensity is fixed at V and varied from θ to 1 million CPS, and the bias voltage of the gas ionization amplification type radiation detector PC is 1400V, 1500V, and 1600V, respectively. fixed to,
This figure shows the relationship between ionization current and pulse peak value when the X-ray intensity is changed in the same way. In both cases, the ionizing current is O
The results are extrapolated so that the peak value becomes 2■ when , and are superimposed on the same graph.

FIG. 3 is a graph showing measurement data when a CrKα star is incident on a gas ionization amplification type radiation detector PC on a cylinder sealed with Ne gas. Gas ionization amplification type radiation detector PC /<Iasumi pressure is 98, respectively.
The graph shows the relationship between the ionization current and the pulse peak value when the X-ray intensity was fixed at 0, 1180V, and 1250V and varied in the same manner as in the experimental example shown in FIG.

Figure 4 shows a gas ionization amplification type radiation detector Pc on a cylinder filled with Ne gas, similar to the experimental example shown in Figure 3.
D. It is a graph showing measurement data when spectra of SKα and SiKα are incident.

As a result, the same data as the measurement data when the spectrum of CrKα shown in FIG. 3 was incident was obtained.

From the data in Figures 3 and 4, log P and ilZ
It can be said that the uniform ionization current i is proportional.

The above experimental results will be further explained using mathematical formulas.

The gas gain G when X-ray intensity N cps having energy Eλ is incident on the gas ionization amplification type radiation detector PC is generally given by the following equation.

G = Go x f (Go, Eλ, N)
-・ltlHowever, Go is xIl! This is the gas gain when extrapolated to a location where I is not incident.

Assuming that the voltage applied to the anode A at this time is ■, Go is given by the following equation (2).

Go-a-eXp (bV) (2) However, a and b are constants.

The measured data also shows that G can be expressed by the following equation.

G-Go -eXp (-ki) ・・・・・・(3)
However, k is a constant and i is the ionization current described above.

This equation (3) is (variable Go of 3 II! in equation 11
,Eλ.

It is shown that the °ζ gas gain G can be expressed by using a single variable i instead of N.

The present invention is based on the above analysis.

A first object of the present invention is to provide a bias voltage correction circuit that corrects the anode voltage of the gas ionization amplification type radiation detector based on the average ionization current i to compensate for fluctuations in the gas gain of the gas ionization amplification type radiation detector. It is an object of the present invention to provide a gas ionization amplification type radiation measuring device that can perform stable measurements by providing the following.

In order to achieve the first object, a gas ionization amplification type radiation measuring device according to the present invention includes a gas ionization amplification type radiation detector and a bias voltage supplying a bias voltage to the gas ionization amplification type radiation detector. A radiation detection device including a generator, an amplifier that amplifies the output of the gas ionization amplification type radiation detector, and a crossing value discriminator that selects a pulse having a crossing value within a certain range from the output of the amplifier,
an averaging circuit that detects an ionizing current generated by radiation incident on the gas ionization amplification type radiation detector and generates an averaged ionizing current value signal corresponding to the averaged current value; and the averaged ionizing current value. The signal i and the gas gain G of the gas ionization amplification type radiation detector of the gas ionization amplification type radiation detector are G = a-exp (bV-k i) where a
, b, and k are constants, so the bias voltage ■ generated by the bias voltage generator is bV=ki
and a bias current correction circuit that supplies a control signal programmed to satisfy the bias voltage generator to the bias voltage generator.

The present invention will be described in more detail below with reference to the drawings and the like.

FIG. 5 is a schematic diagram for explaining the principle of keeping the gas gain G constant by correcting the anode voltage (2) of the gas ionization amplification type radiation detector PC based on the average ionization current i.

ni1 The following equation (4) can be changed from equations (2) and (3) described above.

G=a-exp (bV-k i)...141
The average ionization current of the gas ionization amplification type radiation detector PC is i
A feedback circuit with a feedback constant β is set to correct the anode voltage vo, and the corrected anode voltage V is v-■. +βi. By substituting this equation into the above-mentioned equation (4), the following equation is obtained.

G=a −exp (b (V(, 1βi) ki
)=a-exp (bVo+ (bβ-k)i)・
・ ・ ・ (5) If the feedback constant β is adjusted by 1 so that bβ− in equation (5), equation (5) becomes C;=a−exp (bVo )
This indicates that the gas gain G is controlled to a constant value.

Figure 6A shows an averaging circuit that detects an ionizing current and directly detects an averaged ionizing current value signal i corresponding to the averaged current value from the cathode A side of a gas ionizing amplification type radiation detector PC. FIG. 2 is a circuit diagram showing an example.

The cathode of the gas ionization amplification type radiation detector PC is connected to the long terminal of the amplifier circuit AI included in the averaging circuit without being grounded. A parallel circuit of a resistor R1 and a capacitor CI is connected between the input and output terminals of the amplifier circuit A1, and a parallel circuit of a resistor R1 and a capacitor CI is connected to the output terminal of the amplifier circuit A1.
An averaged ionization current value signal is generated where o=i×RI.

An anode A of the gas ionization amplification type radiation detector PC is connected to a bias voltage generator B via a resistor.

The anode A is also connected to a preamplifier PA.

FIG. 6B shows another embodiment of the averaging circuit in which the averaged ionization current value signal corresponding to the averaged current value is detected indirectly rather than from the cathode A side of the gas ionization amplification type radiation detector PC. FIG.

A signal pulse detected from the anode A side of the gas ionization amplification type radiation detector PC is amplified by a pulse amplifier AIB, and then converted into a pulse from zero volt by a zero level regeneration circuit ZR. Zero level regeneration circuit ZR is capacitor CIB
It is formed from a constant current 11JiR and if diodes DIB and D2B. The signal whose zero level is reproduced is connected to the resistor RI.
The signal is averaged by a smoothing circuit consisting of a B capacitor C2B and outputted via an amplifier A2 and A3. The signal VQ averaged in this way is given by the following equation.

vo=nWp where n is the average number of pulses per unit time, W is the average pulse width, and p is the average pulse waveform value.

Therefore, vg can also be said to be an ilZ equalized current value signal.

FIG. 7A is a circuit diagram showing an embodiment of the radiation measuring device according to the first invention, and this embodiment obtains an averaged ionizing current value signal using the averaging circuit shown in FIG. 6A. ing. In order to match the period characteristics, an amplifier A2 is further provided. The output terminal of this averaging circuit is connected to a bias voltage generator B via a variable resistor VRI for amulating the amount of feedback.

This bias voltage generator B has a reference voltage B1, and a step-up rectifier circuit (voltage-controlled DC-DC converter) that can control the high-voltage output voltage BV is a voltage determined by this voltage. The voltage (when the ionization current of the detector PC is zero) is corrected by a signal transmitted from the ionization current detection section, and a voltage (2) is supplied to the gas ionization amplification type radiation detector PC. This bias voltage generator B is provided with an amplifier A4 forming part of an error amplifier Δ3 feedback circuit. R7 is a resistor for high voltage detection.

The output of the averaging circuit is connected to the input terminal of the error amplifier A3 via the feedback adjustment circuit VR, the reference voltage B1 is connected to the input terminal of the error amplifier A3 via the resistor R4, and the output of the amplifier A4 is connected to the resistor R5. It is connected via ゛ζ.

In this way, as the output i of the averaging circuit increases, a gradually increasing voltage is supplied to the anode A of the gas ionization amplification type radiation detector PC via the resistor 178.

This corrected anode voltage ■ is V−V as described above.
It becomes o+βi. The feedback constant β is determined by the feedback resistor ■R1.
Since the gas gain G is adjusted to be β-, the equation (5) is G=a-exp (bVo), and the gas gain G is controlled to a constant value.

The anode A of the gas ionization amplification type radiation detector PC is input to a preamplifier PA. The configuration after the preamplifier l) A does not differ from the configuration of the conventional device.

The Mil position amplifier PA has a coupling capacitor C3 and an amplifier A5.
It includes a resistor R9 forming a 050 circuit and a capacitor C4 to amplify the output pulse from the gas ionization amplification type radiation detector PC. This output is connected to a wave height discriminator PHA via a waveform shaping circuit 1)S.

The waveform shaping circuit PS includes an amplifier A6, an inductance 121, and a resistor R10, and shapes the waveform of the amplified pulse. Wave height discriminator PHA is amplifier A7, -T limit reference level UL
The comparator C1 has one input terminal connected to R7, the comparator C2 has one input terminal connected to the lower limit reference level 1 and R7, and a reverse open circuit IcO.

The pulse height discriminator PHA discriminates from the output pulses of the amplifier 7 only those having a pulse height between the -T limit reference level UL and the lower limit reference level LL and outputs the same.

That is, in the present invention, by correcting the bias voltage (2) using the average ionization current signal, the gas scale can always be kept constant.

In Fig. 7B, unlike the above embodiment, the ionization current is detected on the anode side of the gas ionization amplification type radiation detector PC while the cathode of the gas ionization amplification type radiation detector PC remains installed, and FIG. 25 is a circuit diagram of a modified example in which the correction voltage is added to the bias voltage. The circuit CA that detects the ionization current of the gas ionization amplification type radiation detector PC and provides a correction voltage is a circuit that operates insulated from the potential of the bias voltage generator WB. Since the inverting input terminal 8 to the amplifier is connected to the anode of the gas ionization amplification type radiation detector 1) C via a resistor with a high resistance value, the ionization current of the gas ionization amplification type radiation detector PC is It will be done manually. A resistor R101 and a capacitor C101 are connected in parallel between the inverting input terminal and the output terminal of the amplifier WA8, whereby the average ionizing current is detected and a resistor R102, R1
It was returned by 03. As a result, a voltage of (1'?IO+.R103.i)/R102 appears across the resistor R103.

Since this voltage is equal to the voltage at the inverting input terminal of the amplifier 8, the anode voltage V of the gas ionization amplification type radiation detector 1)C is given by the following equation.

V=V,) + (RIOI・R]03・i)/
By adjusting the resistance value of RI02 resistor R102,
If 1(RIOI ・R]03) / R102 is equal to the above β, then V=Vo+βi, and as described above, the above equation (5) becomes Q-a-exp (bVo
), and the gas gain G is controlled to a constant value.

A second object of the present invention is to provide an amplifier gain control circuit whose operation is controlled by the average ionization current in order to cancel out fluctuations in the gas gain of the gas ionization amplification type radiation detector by controlling the gain of the gas ionization amplification. It is an object of the present invention to provide a gas ionization amplification type radiation measuring device that can perform stable measurements by being provided in the amplifier.

In order to achieve the second object, the radiation measuring device according to the present invention includes a gas ionization amplification type radiation detector, and a bias voltage generator for supplying a pi'r sumi pressure to the gas ionization amplification type radiation detector. a radiation detector, an amplifier that amplifies the output of an iYt gas ionization amplification type radiation detector, and a peak value discriminator that selects a pulse having a peak value within a certain range from the output of the amplifier, an averaging circuit that detects an ionizing current generated by radiation incident on the gas ionization amplification type radiation detector and generates an averaged ionizing current value signal corresponding to the averaged current value; and the averaged ionizing current value. Since the signal i and the gas gain G of the gas ionization amplification type radiation detector of the gas ionization amplification type radiation detector have a certain functional relationship, the fluctuation of the gas gain G can be controlled by controlling the gain of the amplifier. To cancel, a programmed function generator that generates a function g(i) = c-exp (k i), where c is a constant, and the output of said function generator are connected to one input terminal and the other input terminal. The amplifier is provided with an amplifier gain control circuit comprising a multiplier circuit connected to the output pulse of the gas ionization amplification type radiation detector.

FIG. 8 is a circuit diagram showing an embodiment of this second invention.

Bias voltage generator B is a device that generates a constant bias voltage.It is assumed that the gas gain G of the gas ionization amplification type radiation detector varies, and the gain of the amplifier is controlled to generate nI.
This is an attempt to correct the variation described in I. Average north 1
The circuit shown in FIG. 6A is used as 18D. The structure of the migratory bird discriminator PHA is the same as the structure previously explained in FIG.

+iil N amplifier PA is a normal pulse amplifier and O1I
It consists of a function generator that generates the function g (i), and a multiplication circuit Ml that calculates the product of the output of the pulse amplifier MiJ and the output of the function generator.

If the output of Ail's pulse amplifier-PA is X, then xLj
It can be considered that it is proportional to the gas gain G of the force ionization amplification type radiation detector PC. The product of the output of the multiplier circuit Ml (YX and the output g of the function generator (i)
i) =kl・G(,-exp(-k i)・g(i)
However, 1 is given as a constant.

Let the output g (i) of the function generator, which is a function of i, be g (i) = c − exp (k i) so that this value is constant.

As a result, the output of preamplifier PA becomes x-g(i) equal to 1
・GO-C becomes constant regardless of 1, gas gain G
Fluctuations in are corrected. The subsequent processing is the same as that described above with reference to FIG.

1. That is, in this second invention, the variation in gas gain G is corrected by correcting the gain of preamplifier PA as described above.

A third object of the present invention is to control the fluctuation of the gas gain of the gas ionization amplification type radiation detector by controlling the upper and lower limit levels of the migratory bird discrimination circuit of the 1111 wave high value detector based on the ionization current. It is an object of the present invention to provide a gas ionization amplification type radiation measuring device that can perform stable measurements by providing a detection level correction circuit for canceling the wave height discriminator.

In order to achieve the third object, a gas ionization amplification type radiation measuring device according to the present invention includes a gas ionization amplification type radiation detector and a bias voltage supplying a bias voltage to the gas ionization amplification type radiation detector. A radiation detection device including a generator, an amplifier that amplifies the output of the gas ionization amplification type radiation detector, and a peak value discriminator that selects a pulse having a peak value within a certain range from the output of the amplifier,
an averaging circuit that detects an ionizing current generated by radiation cotton incident on a radiation detector of a gas ionization amplification type and generates an averaged ionizing current value signal corresponding to the averaged current value; Since the current value signal i and the gas gain G of the gas ionization amplification type radiation detector of the gas ionization amplification type radiation detector have a certain functional relationship, fluctuations in the gas gain G are detected by the peak value discriminator.・〈In order to control and cancel the
ki, a constant, and a multiplier circuit in which the output of said function generator is connected to one input terminal and a constant voltage to the other input terminal. The pulse height discriminator is provided with a detection level correction circuit for correcting the detection level.

FIG. 9 is a circuit diagram showing an embodiment of this third invention.

In this embodiment, the circuit shown in FIG. 6B is used as the averaging circuit.

The output of the averaging circuit is i is a function h as shown in the above equation.
(i) is connected to a function generating circuit that outputs. E
r is a constant voltage generating circuit, and the above-mentioned Er and h (i) are connected to the input terminal of the multiplier circuit M2. The output of the multiplier circuit M2 is the upper limit reference level t of the pulse height discriminator PHA.
Variable resistor VR2 that determines JL and lower limit reference level 17
i to adjust the voltage between the terminals of variable resistor VR3 that determines L
Configure an iJ variable voltage source. Fluctuations in the gas gain G can be corrected by adjusting the reference levels U and Ll in n:1 ratio to be proportional to the fluctuations in the gas gain G using the outputs of the multiplication circuits li & M2.

Letting the output of the preamplifier PA be X, X is proportional to the gas gain G.

Therefore, since the output of x=2・Go−exp(−k +) multiplication circuit M2 is Er−h(i), +(i
) = d-exp (-k i) However, if d is a constant, then Er-h(i) = Er -d-exp (-k i) and is proportional to X.

That is, in this invention, the i provided in the pulse height discriminator PHA
A detection level correction circuit consisting of a preprogrammed function generator and a multiplier circuit M2 in which the output h (i) of the function generator is connected to one input terminal and a constant voltage Er to the other input terminal, By correcting the pulse detection level of the wave discriminator PHA, fluctuations in the gas gain G can be canceled out.

A fourth object of the present invention is to provide a zero level correction circuit in the pulse height discriminator that cancels fluctuations in the gas gain of the gas ionization amplification type radiation detector by controlling the zero level of the amplifier output based on the ionization current. It is an object of the present invention to provide a gas ionization amplification type radiation measuring device that can perform stable measurements by providing it at the front stage.

In order to achieve the fourth object, the gas ionization amplification type radiation measuring device according to the present invention supplies a gas ionization amplification type radiation detector and a bias voltage to the gas ionization amplification type radiation detector) <Radiation detection including an Iasumi pressure generator, an amplifier that amplifies the output of the gas ionization amplification type radiation detector, and a peak value discriminator that selects a pulse having a peak value within a certain range from the output of the amplifier In the apparatus, an averaging circuit detects an ionizing current generated by radiation incident on the gas ionization amplification type radiation detector and generates an averaged ionizing current value signal corresponding to the averaged current value; Since the ionization current value signal 1 and the gas gain G of the gas ionization amplification type radiation detector described in iii. In order to control and cancel the zero level, the following function j (i) −j! -d-exp (-k i) However, N, d.

k is a constant; and a summing circuit, the output of the function generator being connected to one input terminal and the output pulse of the gas ionization amplification type radiation detector being connected to the other input terminal. A zero level correction circuit consisting of the following is provided in the preceding stage of the pulse height discriminator.

FIG. 10 is a circuit diagram 1 showing an embodiment of this fourth invention. In this embodiment, the circuit shown in FIG. 6B is used as the averaging circuit.

The output of the averaging circuit is i is a function j as shown in the above equation.
(i) is connected to a function generating circuit that outputs.

The zero level correction circuit Z provided before the pulse height discriminator includes a function generation circuit j (i) and an adder circuit S (rarely). The output j (i) of this function generation circuit is The output is connected to an adder circuit (DC component insertion circuit) S. At the output of the adder circuit S, an output obtained by inserting the DC component j (i) into the output P of the preamplifier PA appears. The pulse height discriminator PHA includes a comparator CI having one input terminal connected to the upper limit reference level UL, a comparator C2 having one input terminal connected to the lower limit reference level LL, and a reverse opening circuit. The level is fixed and does not depend on the output of the averaging circuit as explained in FIG. 8.The pulse height discriminator PHA determines the upper limit reference level UL from the output pulse of the adder S Only those having wave heights between and the lower limit reference level LL are discriminated and output.

When the output of the preamplifier PA is P, P is proportional to the gas gain G, the amplification factor of the preamplifier PA, 3, and the signal S, and is given by the following equation.

P=s k3・Go-exp(-k i) When the signal is S, the output Ss of the adder circuit S is 5s=P+j (i) -s-3・Go-exp(-k i)+ρ-d ・
exp(-ki) =1+ (3・Go to s-d) ・exp(
-k i) Exp(-ki) of the function generated by the function generator
) is the count d = S1・k3・co, then 5s=
J+sll<3・Go (s/5l-1)exp(-
ki) When the signal 5=sl, the output of the adder circuit S becomes p, which is a constant value l that is unrelated to the gas gain G.

In this example device, there is a problem in that as the signal S moves away from 5=sl, a component of exp(-ki) remains and complete correction is not performed. However, if a single spectrum is measured and there is no interference spectrum. available for.

As explained above, each invention provides an averaged ionizing current value signal i
The gas gain G of the gas ionization amplification type radiation detector of the gas ionization amplification type radiation detector is G = GO-ex.
By utilizing the constant functional relationship p (-k i), fluctuations in the gas gain G are prevented. When there are fluctuations in the gas gain G, the gain of the Ail position amplifier PA or the wave direction discriminator is Figure 1 shows a gas ionization amplification type radiation measurement device that can perform stable measurements with high accuracy by supplementing the PHA detection level. FIG. 2 is a block diagram showing the basic configuration of the device.

FIG. 2 is a graph showing the average ionization current i of the waste ionization amplification type radiation detector PC and the pulse height of the detection pulse signal corresponding to the average ionization current i when X-rays of constant energy are incident.

FIGS. 3 and 4 are graphs in which measurements were taken with different radiation spectra and similarly normalized.

FIG. 5 is a schematic diagram for explaining the first invention in detail.

Figure 6A shows an embodiment of the averaging circuit configured to directly detect the average ionizing current. Figure 13 shows an ip equalization circuit configured to indirectly detect the average ionizing current. An example of the circuit is shown in the circuit diagram.

Ru.

FIG. 7A is a circuit diagram illustrating an embodiment of the radiation a measuring device according to the first invention.

FIG. 7B is a small circuit diagram of another embodiment of the radiation measuring device according to the first invention.

FIG. 8 is a circuit diagram of an embodiment of the radiation measuring device according to the second invention.

FIG. 9 shows the actual radiation measuring device according to the third invention.
Eight examples are shown in small J circuit diagrams.
- Figure 10 shows radiation at according to the fourth invention.
FIG. 2 is a circuit diagram showing an example of an im device; FIG.

PC...Gas ionization amplification type radiation detector 1...Bias voltage generator 1) A...Tl1l fiL
Amplifier 1) HA... Wave height discriminator r]...
・11 equalization circuit 1) V...rising ratio rectifier circuit P
S...Waveform shaper Z...Zero level supplement +1-8 circuit off diagram (B) Procedural amendment 1. Indication of the case 1982 Patent Application No. 70844 2, Title of the invention Radiation measuring device 3, Person making the amendment Relationship to the case Patent applicant 4, Agent Contents of the amendment (Patent Application 1982-70844) (1) ) The scope of claims is amended as follows.

[2. Claims (1) A gas ionization amplification type radiation detector, a bias voltage generator supplying a bias voltage to the gas ionization amplification type radiation detector, and the gas ionization amplification type radiation detector. In a radiation detection device including an amplifier that amplifies the output of the amplifier, and a peak value discriminator that selects a pulse having a peak value within a certain range from the output of the amplifier, the radiation incident on the gas ionization amplification type radiation detector an averaging circuit that detects the ionizing current generated by and generates an averaged ionizing current value signal corresponding to the averaged current value, and the averaged ionizing current value signal i and the gas ionization amplification type radiation detector@ Since the gas gain G is given by the following formula, direct distribution V-■.

A radiation measurement device comprising: a bias current correction circuit that supplies a control signal programmed to satisfy +k i /b to the bias voltage generator.

G=a −exp(bV−k i) where a and b are constants (2) and a bias voltage is supplied to the gas electric %Ill amplification type radiation detector and the gas ionization amplification type radiation detector. A radiation detection device including a bias voltage generator, an amplifier that amplifies the output of the gas ionization amplification type radiation detector, and a peak value discriminator that selects a pulse having a peak value within a certain range from the output of the amplifier. an averaging circuit that detects an ionizing current generated by radiation incident on the gas ionization amplification type radiation detector and generates an averaged ionizing current value signal corresponding to the averaged current value; Since the current value signal i and the gas gain G of the gas ionization amplification type radiation detector have a certain functional relationship, the following function g ( 1) consisting of a programmed function generator for generating the function generator and a multiplier circuit in which the output of the function generator is connected to one input terminal and the output pulse of the gas ionization amplification type radiation detector is connected to the other input terminal; A radiation measurement device characterized in that the amplifier is provided with an amplifier gain control circuit.

Note g (i) -c-exp(k i) where c is a constant (3) A gas ionization amplification type radiation detector and a bias voltage generation supplying a bias voltage to the gas ionization amplification type radiation detector. a radiation detector, an amplifier that amplifies the output of the gas-electric 1illt amplification type radiation detector, and a peak value discriminator that selects a pulse having a peak value within a certain range from the output of the amplifier, an averaging circuit that detects an ionizing current generated by radiation incident on the gas ionization amplification type radiation detector and generates an averaged ionizing current value signal corresponding to the averaged current value; and the averaged ionizing current value. Since the signal i and the gas gain G of the gas ionization amplification type radiation detection H have a certain functional relationship, 2. In order to cancel the fluctuation of the gas gain G by controlling the detection level of the pulse height discriminator. The following function h(1)
It consists of a programmed function generator that generates A radiation measurement device characterized in that the wave height discriminator is provided with a detection level correction circuit for correcting the wave height discriminator.

h (i) -d-exp (-k i>where d is a constant (4); a gas ionization amplification type radiation detector; and a bias voltage that supplies a bias voltage to the gas ionization amplification type radiation detector. A radiation detection device including a generator, an amplifier that amplifies the output of the gas ionization amplification silent radiation detector, and a peak value discriminator that selects a pulse having a peak value within a certain range from the output of the amplifier, an averaging circuit that detects an ionizing current generated by radiation incident on the gas ionization amplification type radiation detector and generates an averaged ionizing current value signal corresponding to the averaged current value; and the averaged ionizing current value. Since the signal j and the gas ionization amplification type radiation detector @ gas gain G have a certain functional relationship, in order to cancel the fluctuation of the gas gain G by controlling the zero level of the output pulse of the amplifier, the following and a summing circuit in which the output of the function generator is connected to one input terminal and the output pulse of the gas ionization amplification type radiation detector is connected to the other input terminal. A radiation measurement device characterized in that a zero level correction circuit is provided upstream of the wave height discriminator.
Note j (i) = 1-d-exp(-k i) where n
, d is a constant (5).The averaging circuit outputs the averaged ionization current value signal l directly from the cathode of the gas ionization amplification type radiation detector PC, or outputs the output pulse from the radiation detector P node. The radiation measuring device according to claim 1, 2, 3, or 4, which is configured to indirectly take out the radiation after amplification. (2) Correct the "wave height discriminator D" in the first line of page 7 of the specification to a single wave height discriminator PHAJ.

(3) Delete "1 of 1 gas ionization amplification type radiation detector" from line 15 to line 16 of page 12 of the specification.

(4) Specification page 12, line 19 (7) rbV=ki1
rv=v. Correct to +k i / b J.

(5) "Bias current correction circuit" in the first to second lines of page 13 of the specification is corrected to "bias voltage correction circuit".

(6) "From line 1I to line 12 of page 13 of the specification"
If the average ionizing current is i, a feedback circuit with a feedback constant β is provided.
The average ionization current i is passed through a feedback circuit with a feedback constant β to be corrected.

(7) Correct "period polarity" in the first line of page 16 of the specification to "polarity."

(8) From line 6 to line 15 on page 16 of the specification, [this bias voltage generator B is a resistor]. -1 is deleted.

(9) r V Rj on page 16, line 17 of the specification [V
Correct to RIJ.

(10) Correct "amplifier A5050 circuit" from line 13 to line 14 of page 17 of the specification to "amplifier Δ5 feedback circuit".

(11) [Inductance I, 1” from page 17, line 18 to line 19 of the specification is 1 delay line DLIJ
Correct to.

(12) "1 in Figure 7B" on page 18, line 11 of the specification is corrected to "Figure 7B is".

(13) On page 18, line 12 of the specification, 1... was installed" is amended to "...was installed."

(14) Correct "25 circuit diagram" on page 18, line 16 of the specification to "circuit diagram shown."

(15) "Insulated on..." on page 18, line 18 of the specification is changed to "riding on..." in the sleeve IL4-.

(16) r on page 22, line 12 to line 13 of the specification
X−g(i) is 1・G,・c” [x・g (i)=
Correct to kl-Go-cl.

(17) Specification page 23, line 19 to page 20, line 1-
Delete "(Gas ionization amplification type radiation detector)".

(18) [Output is i] j on page 24, line 14 of the specification
The expression 11 indicates...'' is corrected to ``The output i is expressed by the above expression...''.

(19) 1- from page 27, line 2 to line 3 of the specification
" of gas ionization amplification type radiation detector" is deleted.

(20) On page 27, line 17 of the specification, change "The output i is indicated by the above formula..." to [The output i is indicated by the above formula...
].

(21) Delete "of a gas ionization amplification type radiation detector" on page 29, line 18 of the specification.

(22) Amend the furigana of the inventor's name in the application as in the correction application.

(23) Figures 1, 5, 6, and 7 of the attached drawings,
Figure 8 is attached to Figure 1, Figure 5, Figure 6, and Figure 7, respectively.
Figure 8 is corrected.

Above Figure 1 Figure 5' Figure A-6 (A) - Figure A-6 (B) Procedural amendment 1. Indication of the case 1982 Patent Application No. 70844 2, Title of the invention Radiation measuring device 3, Person making the amendment Patent applicant 4, Agent [Amending to reference voltage BIJ.

Claims (5)

[Claims] (1) a gas ionization amplification type radiation detector; a bias voltage generator that supplies a bias voltage to the gas ionization amplification type radiation detector; and an amplifier that amplifies the output of the gas ionization amplification type radiation detector; and a peak value discriminator that selects a pulse having a peak value within a certain range from the output of the amplifier, the radiation detection device detecting an ionizing current generated by radiation incident on the gas ionization amplification type radiation detector. an averaging circuit that generates an averaged ionization current value signal corresponding to the averaged current value; and a gas ionization amplification type radiation detection unit of the gas ionization amplification type radiation detector using the averaged ionization current value signal i. Since the gas gain G of the device is given by the following formula, the bias current that supplies the bias voltage generator with a programmed control signal so that the bias voltage ■ generated by the bias voltage generator satisfies bV=ki A radiation jti11 device characterized in that it is constructed from a correction circuit. Note G=a-exp (bV-k i) However, a, b,
is a constant (2) A gas ionization amplification type radiation detector, a bias voltage generator supplying a bias voltage to the force separation amplification type radiation detector, and amplifying the output of the gas ionization amplification type radiation detector. In a radiation detection device including an amplifier and a peak value discriminator that selects a pulse having a peak value within a certain range from the output of the amplifier, an ionizing current generated by radiation incident on the gas ionization amplification type radiation detector is detected. an averaging circuit that detects and generates an averaged ionization current value signal corresponding to the averaged current value; and a gas ionization amplification circuit for the 1V, the averaged ionization current value signal i, and the gas ionization amplification type radiation detector. Since the gas scale G of the radiation detector has a certain functional relationship, in order to cancel the fluctuation of the nil gas gain G by controlling the gain of the amplifier, the following function g (i) is programmed to be generated. The amplifier gain control circuit is comprised of a function generator and a multiplier circuit in which the output of the Ail function generator is connected to one input terminal and the output pulse of a gas ionization amplification type radiation detector is connected to the other input terminal. A radiation measuring device characterized in that it is configured by being installed in an amplifier. Note g (i) = c ・exp (k i) However, c is a constant (3) a gas ionization amplification type radiation detector; a bias voltage generator that supplies a bias voltage to the gas ionization amplification type radiation detector; and an amplifier that amplifies the output of the gas*m ring type radiation detector. and a pulse height value discriminator that selects a pulse having a pulse height value within a certain range from the output of the amplifier described in iii). an averaging circuit that detects the ionizing current generated by the ionizing current and generates an averaged ionizing current value signal corresponding to the averaged current value; Since the gas gain G of a gas ionization amplification type radiation detector has a certain functional relationship, the gas gain G
In order to cancel the fluctuation of by controlling the detection level of the 111 wave high value discriminator, the output of the programmed function generator that generates the function h(i) of the F function and the output of the 1III function generator are connected to one input terminal. and a multiplier circuit whose other input terminal is connected to a constant voltage, and the output of the multiplier circuit causes Ai
A radiation measurement device characterized in that the wave height discriminator is provided with a detection level correction circuit for correcting the detection level. Note h (i) = d-exp (-k i) where d is a constant (4) A gas ionization amplification type radiation detector, a bias voltage generator that supplies a bias voltage to the gas ionization amplification type radiation detector, and an amplifier that amplifies the output of the gas ionization amplification type radiation detector. and a peak value discriminator that selects a pulse having a peak value within a certain range from the output of the amplifier described in 1iii. an averaging circuit that detects and generates an averaged ionization current value signal corresponding to the averaged current value; and a gas ionization amplification type radiation detector that uses the averaged ionization current value signal Since the gas gain G of the radiation detector has a certain functional relationship, a programmed function generator generates the following function in order to cancel the fluctuation of the gas gain G by controlling the zero level of the output pulse of the amplifier. The output of the function generator is connected to one input terminal, and the output pulse of the gas ionization amplification type radiation detector is connected to the other input terminal. 1. A radiation measuring device characterized in that it is provided in a "C" configuration.
) However, 1. d is a constant (5) The averaging circuit outputs the averaged ionization current value signal 1 directly from the cathode of the gas ionization amplification type radiation detector PC, or by insulating it to the anode side of the radiation detector 1''C and outputting it from the anode. Claims 1 and 2 are configured to indirectly extract the pulse after amplifying the pulse.
The radiation measuring device according to item 3 or 4.