JPH04158209A - Radiation thickness meter and measuring method of thickness by using radiation - Google Patents

Abstract

PURPOSE:To dispense with a radiation detecting element and thereby to simplify construction and to facilitate manufacture and maintenance by using a pressure gauge and a thermometer measuring the pressure and temperature of a gas respectively. CONSTITUTION:A radiation detector 4 disposed opposite to a radiation source 2 at a prescribed gap G detects a radiation 2a and outputs a first detection signal 4a. A preamplifier 6 converts this signal into a voltage signal and outputs a second detection signal 6a having a voltage E. A pressure gauge 18 detects the pressure P of a gas 12 in a measuring space 5, while a thermometer 19 detects the absolute temperature T thereof, and they output a pressure signal 18a and a temperature signal 19a respectively. A signal processing element 20 receiving the signals 6a, 18a and 19a as inputs stores a value Eoa of the voltage E, a value Pa of the pressure P and a value Ta of the temperature T obtained by input of a first control signal 20a, at the time t1 in a state wherein a substance 11 to be measured is not inserted into the space 5. Besides, it computes the right member of an equation by using a voltage value Ex, a pressure value Pb and a temperature value Tb obtained by input of a second control signal 20b at the time t2 later than the time t1 and also the values Eoa, Pa and Ta, and outputs a thickness signal 20c showing X as a result. According to this constitution, the measurement of a thickness is enabled.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a radiation thickness meter that measures the thickness of an object based on the dose of transmitted radiation after passing through the object. and a thickness measurement method using radiation.

More particularly, the present invention relates to a thickness gauge and an F thickness measuring method that can facilitate the production and maintenance of the radiation-tablet gauge.

[Conventional technology]

FIG. 3 is a configuration diagram of a conventional radiation thickness meter 1.

In the figure, the 24-wire #trough device 3/2: accommodated radiation source, 44@77, 2' is placed opposite to the measurement space 5 with a predetermined interval G, and the source 2 emits radiation. A radiation detector 6 detects radiation a2a and outputs a first detection signal 4a corresponding to the dose of detected radiation #2m. A preamplifier is designed to output a second detection signal 6a having a voltage E proportional to , and 7 is a mounting frame to which the detector 4 and amplifier 6 are fixedly attached. Reference numeral 8 denotes a mount to which the container 3 and the mounting frame 7 are fixed so that the radiation source 2 and the detector 4 maintain the above-mentioned relational arrangement, and 9 represents the above-mentioned radiation source 2.
A radiation detection unit consisting of a stand 8 and a stand 8, 1 is a work detection signal 6a
is input, and the voltage value E/c represented by the signal 6a is subjected to storage and calculation described later, and a paper-like or plate-like measured object #! is inserted as shown in the blank space 5. 111 thickness
The radiation thickness meter 1 is composed of the above-mentioned ejection part 9 and the processing part 1o.

The thickness gauge 1 is configured as described above, and as a result, the radiation 2a incident on the object to be measured 11 is attenuated in accordance with the thickness X of the object to be measured 11 and is incident on the radiation detector 4 (since Measurement space 57 (value Bx of voltage E exhibited by detection signal 6a when object to be measured 11 is inserted) x is expressed as the right side of equation (2), where E.

is when the thickness X of the object to be measured 11 is zero, that is, the space 5
The value of voltage E when the object to be measured 11 is inserted into UI! I is the absorption coefficient of the object to be measured 11 for the radiation 2a#c, Dt! 1 is the density of the object 11 to be measured.

Ex=E0-eXp (-Uffl value Dm@x) ---
...(4) However, since equation (6) is derived from equation (S), if the thickness is 19 tones, then 5111 iE' i /
-Kenka Hani- Sensitive fDm is the word in advance! 6 Science Department 10 (It is memorized, it is. Blank space 5/C covered - J11 Memoir 1
Time when 1 is not inserted [processing unit 1 at 3]
0, the process e10 stores the voltage value Eo at time [,].

Furthermore, the object to be measured 11 is placed in the sky vr5 at a time better than 3.
It looks like it has been inserted! ! ! By inputting the second punctuation signal 10C to the sixth section 10 at time [4].

The processing unit 10 calculates the voltage E exhibited by the signal 6a at time [,
The processing unit 10 calculates the right side of equation (5) using the value Ex and the order values Um-Dm and Eo, and outputs the above-mentioned thickness signal 10a representing X on the left side of equation C9. It is configured. Therefore, according to the thickness gauge 11C, the signal IQa/c
Therefore, the thickness X can be measured.

x=-(t/(UIt1@D-)I-tn(Ex/Eo
＞-・-・C5) [Section to be solved by Invention 1, top] With the thickness gauge 1, C is L℃ as described above.Thickness X is measured, but in this case, the radiation 2a is actually C is the object to be measured 1
1 as well as the void 5 (existing air-like gas 12
Among them, -jtC decays, and as a result, the above-mentioned voltage value Eo
Let the value of the voltage E exhibited by the signal 61 when there is nothing in the cavity 5 to attenuate the radiation edge 2a be "0 (1), and let U□ be the absorption coefficient for the radiation #J2! of the gas 12, And, if the density of the gas 12 at the aforementioned time t3 is Da, it will be expressed by the equation (0), where (density Da is a quantity that changes over time, so Eo is determined as a constant determined in advance by measuring Eo in advance). The thickness measurement method lc, which calculates the thickness X by calculating the right side of the equation 1, is based on the change in density Da over time (this includes measurement errors).

E, =E0.・eXp(-Uae[)a@G]…(1
) −・・−,・((3) Therefore, in the case of thickness gauge 1, in order to avoid measurement errors due to changes in r−D in the thickness signal l0a over time, each time Ex is measured, Beforehand.

Alternatively, it is necessary to interrupt the measurement of Ex and measure B, so there is a problem that the work of measuring the thickness is troublesome.For this reason, the radiation thickness meter 13 with IRK shown in Fig. 4 is adopted. It has been conventionally known to solve the above-mentioned problems by

Then, Fig. 4/cS 1:, where V differs from Fig. 3, measurement space 1 with exactly the same dimensional configuration as measurement space 5 with interval G.
The radiation l in Fig. 3 is arranged such that the space 14 and the space 5 are short, and there is a delay due to the long and thick communicating path.
@ Radiation detection section 1 configured exactly the same as detection section 9 451
In addition to the detection unit 9, the detection signal 6a outputted by the detection unit 9 and the signal 61 outputted by the ejection unit 15 (corresponding to By providing the signal processing section 16 to which the detection signal 15a is input, in this case, the space 14 (is the object to be measured 11).
Since the radiation detection unit 15 is configured such that the radiation detection unit 15 is not inserted, the detection signal 151 always corresponds to the change in the density Da of the gas 12 over time (it exhibits the voltage value E0 on the left side of Equation 51. In FIG. 4, the signal processing unit 16
is configured to perform the calculation on the right side of equation (52) using the voltage value Ex that the signal 61 always exhibits and the voltage value E that the signal 15a always exhibits to output the signal 16a representing the X on the left side of the expression (5). It has been done.

Radiation@thickness gauge 131 detection units 9 and 15 and signal processing unit 16
It is made up of.

The thickness gauge 13 is as described above (aCi5!).

It is clear that an accurate thickness measurement without any errors can be made by the signals 16a/c, but in the case of this thickness gauge 13, the detection B9
Two sets of radiation detection sections having the same configuration as the radiation source 2. which constitutes the detection sections 9 and 15 are required. # Source container 3. Since both the radiation detector 4 and the IJ amplifier 6 require troublesome work to manufacture, the structure of the thickness gauge 13 is complicated, and as a result, there is a problem that manufacturing and maintenance of the thickness gauge 13 are not easy.

The purpose of the present invention is to use a gas 1 instead of the radiation detection section 15.
The purpose of the present invention is to simplify the structure of the thickness gauge by using a pressure gauge and a positioning needle for measuring pressure and temperature, thereby making the thickness gauge easy to operate and maintain. .

[Means to solve the problem]

In order to achieve the above objects, the present invention includes a radiation source, a radiation source (with respect to which power is distributed facing each other via a measurement space having a predetermined interval G, and a radiation edge emitted by the radiation source). a radiation detector that detects and outputs a first detection signal according to the detected radiation 1nstic; and a second detection that converts the first detection signal into a voltage signal and amplifies it to have a voltage E proportional to the dose. a preamplifier that outputs a signal; and a pressure gauge that detects the pressure P of gas in the measurement cavity and outputs a pressure signal representing the pressure P.

a thermometer that detects the absolute temperature T of the gas in the measurement cavity and outputs a temperature signal representing the absolute temperature T; the second Yokota signal, the pressure signal, and the temperature signal are input; No object to be measured is inserted into the measurement space! Time t in 1.

By inputting the first control signal at the time tI
The value Eoa of the voltage E of the second detection signal at K and the time t, the value Pg1 of the pressure P represented by the pressure signal at VC and the value Ta of the absolute temperature T represented by the temperature signal at time t. and by inputting the second control signal at a time t later than the time t1, the voltage E of the second run-in signal at ``CmCm side 1. Using the value Pb of the pressure P represented by the pressure signal at the time [, the value Tb of the absolute temperature T represented by the temperature signal at the time, and the stored values E of °Pa and Ta, 1) a signal processing unit that performs calculations on the right side and outputs a thickness signal representing the calculation result X; Measure the radiation thickness with a thickness meter at ℃, here.

UIlfi is the radiation of the object to be measured! I (absorption coefficient for

D is the density of the object to be measured.

U8 is the absorption coefficient of the gas for the radiation.

M is the molecular weight of the gas, B is the universal gas constant.

Configure the radiation thickness gauge as follows.

! =-(1/(U!n@Dm) l-[tn(Ex/E
oa)+U, -((P b/Tb ) (P a/T
a) l・(M/R)・G]...(1) Also according to the present invention.

A radiation source and a predetermined distance G? A radiation source 1ilJ! which detects a radiation beam emitted by the radiation source and outputs a first detection signal corresponding to @i[ of the detected radiation; a detector, a preamplifier for converting the first run-in signal into a voltage signal and applying it as a second detection signal having a voltage E proportional to the a1/C; an output meter that detects pressure P and outputs a pressure signal representing the pressure P;

a thermometer that detects the absolute temperature T of the gas in the measurement cavity and outputs an a degree signal representing the absolute temperature T; Time t when no measurement object is inserted @
, by inputting the first control signal at the time t.
, /c and the value PR of the pressure P represented by the pressure signal at the time t.

The value Ta of the absolute temperature T represented by the temperature signal at
, and set the time to a time later than the child's time 1. By inputting a second control signal, the value Pb of the pressure P represented by the pressure signal at the time t1 and the value T of the absolute temperature T represented by the temperature signal at the time 1t are changed.
a first signal processing unit that performs a calculation on the right side of (2) using b and the storage boxes Pa and Ta and outputs a change signal representing ΔDa of the calculation result; and the density change signal are input, and the first suppressing signal is inputted at the time [I, so that the time [1/c
: F6 indicates the value Eoa of the voltage E of the second detection signal, and the second control signal is manually input at the time 1, so that the value of the second detection signal at the time t, + is l1g of the voltage E, the ΔDa represented by the density change signal from the time 1 to f4c, and the stored value Fi.
G) a second signal processing unit that performs a calculation on the right-hand side using G) and outputs a thickness signal representing the result of this calculation, This is a radiation thickness meter that measures the thickness X of an object to be measured.

here/c.

M is the molecular weight of the gas.

R is the universal gas constant.

Ul is the absorption coefficient of the object to be measured for the radiation.

Dm is the height of the object to be measured.

Set the radiation source meter so that the absorption coefficient of the gas for the radiation 9 is.

ΔD a== ((Pb/Tb)-(Pl/T3)
l ・(M/R) Decoy・・C2>x= −(l/(Ur
naDff(1) l”(tn (Ex/E0.)+U
a@ΔDa@G1 (3) Furthermore (1 according to the present invention).

radiation 'aTN, and a first detection according to the dose of the radiation detected by detecting the radiation emitted by the radiation source, which is arranged opposite to each other via a measurement space having a predetermined interval G between the radiation detectors; A radiation detection src sensor comprising a radiation detector that outputs a signal, and a preamplifier that converts the first detection signal into a voltage signal, amplifies it, and outputs it as a second detection signal having a voltage E proportional to the dose. Measure the density Dm of the object and the absorption coefficient Ua of the gas in the measurement space for the radiation; a first step of storing each measured value;

The value E of the voltage E of the second detection signal at time [1] when the object to be measured is injected into the measurement space and is in a low position. Along with remembering a.

The time monitor measures the pressure P of the gas in the measurement space and stores the pressure value Pa of the measurement result, and at the time 1. The absolute @fT of the gas in the measurement cavity at
and a third step of measuring the mtL and T values of the measurement results.

Storing the value Ex of the voltage E of the second detection signal at a time t later than the time t1, and measuring the pressure P of the gas at the 1st constant space at the time 1; a third step of storing the pressure value Pb of the measurement result, and measuring the absolute temperature T of the gas in the measurement space at the time t, and storing the temperature value Tb of the measurement result;

Each of the stored values Unn' stored in the first to third steps
Dffl"a' E0a, Pa"r8. EX, Pb
and a fourth step of performing (1) operation 1 of the right-hand side using (1) and Tb, and the above (
1) Left side 1) A method of measuring radiation, where x is the measured value of the value of the g1 constant object, and 22Il
c.

Uo is the absorption coefficient of the 4vL measurement object for the radiation.

DB rl FTo 4e a,jIt i thing'3
FJ! K and Ua are the absorption coefficients for the previous radiation Δ.

Mis Molecular weight of the gas.

R is the universal gas constant A thickness measurement method using a radiation set is constructed as follows.

X = −+ 1/(Urn-D, > l・Cl n
(Ex/E.3)+U, -[F'fi/T
o )-(Pa/Ta) 1.lid/R)-G:)-
...= (1) [Effect] If we configure the sea urchin above, it is clear that the equation (1J) can be obtained from the equations (23 and (31), and the CD equation becomes the equation 6)/C2 gas crawling pressure It can be proven as described below that the formula takes into account changes based on changes in !WitDa of the gas in the measurement space of value E0. Therefore, according to the present invention, both of the above The above-mentioned one radiation detection unit 150, which is equipped with a radiation source 2, a radiation source capacity 1s 3, a radiation detector 4, and a preamplifier 6, which requires a cumbersome work; unnecessary, and the pressure and temperature of the above gas is By using a pressure gauge and a thermometer that detect It will be possible to do it.

[Actual example]

FIG. 1 is a block diagram of an embodiment 17 of a radiation thickness meter according to the present invention. In this figure, the same components as those in FIG. 3 (the same reference numerals as in FIG.

In FIG. 1, 18 is a pressure gauge that detects the pressure P of the gas 12 in the measurement space 5 and outputs a pressure signal 18a representing this pressure P; 19 is the pressure gauge of the gas 12 in the measurement space 5;
A temperature signal 1 representing this temperature IfT by detecting the absolute a degree T of
m that outputs 9a [total, 20 is preamplifier 6]
6”-Output second detection signal 6a, pressure signal 18a, temperature signal 19m, and !11 control signal 20a and second control signal 20
b is input, and these signals are used to perform the signal fiF1, which will be explained below, and output the output signal 20C. 19 and the signal processing section 2o constitute an fR.

Since the total thickness 17 is composed of the above-mentioned 5+ degrees Celsius, the above-mentioned ``Kaisei value Eo &
6) As shown in the equation, the temperature will change depending on the density Da of the gas 12, and the time at which the measurement space 5 and the object to be measured 11 are not inserted is now ℃. ! When 1 and Da are 1, the voltage E0 becomes E. If it is a (fTJ formula is obtained from formula 61, and 1 time t.

When the time is better than that, the density Da is Da□ and the voltage E0 is E
. If it is b, then equation 3) is obtained from equation (6), so if Da2""Dal+ΔDa, equation 9) is derived from equation ① and equation d).

”oa=Eoo・exP(Ul・Da+”G)=
= (Eoo;”oo” exP (Ul ・D
Bz・G) ・−”= (g)EOt) =
Eg3' eXp (-(J aaΔDJl'G)
-= (9) Detection signal 6a at the above time
If the voltage around ED exhibited by is Ex, then T51
E of the formula.

is E in equation (9). Assuming that bVC is equal to 9, the density Daf') change over time ΔDa Analysis and Dedication - Correctly determine the 1-v length

χ=-11/(U, ・Dka))・tzn (F;, /E
o3) +U, .

ΔD, -Gl4-・(y)) L (2, 2 = 1 formula 12o) Assuming that it is a gas, M is the molecule of gas 12 -, R is *a gas constant, and the quality tW The relationship O expressed by Kawabe's equation (11) is between the 12 gases 1 occupied by g, V, and the pressure and temperature P, T of this gas 12.
Ariari 2 Also, the above-mentioned density, and oath 1 between W and @I V y
r +x Since there is the relationship of equation (12), equation (13) can be obtained from equation (11) and equation (12).

PV-W-(R/M)-T Decoy-(value)D,
= WlV song... (12) Da=
{P/T)-(M/R)-- (13) Therefore, at the above-mentioned time [, the pressure of the gas 12 and the
: , are P, , Ta, respectively, and the pressure and temperature o1 at the above time I,
; t”-Zoba Pb, Tb and 1 time t
.

De J] Sea Shark I) 3. The above-mentioned i J D 3-D ;12 0al+S (13
) ceremony (moyuzu(・te(14) ceremonybi)・yo5 ni;'7
``1 no) @ y) [x4) formula b) ΔD3 (10
) expression (by substituting and , the expression (T5) becomes tt
”:r:Toenaro.

ΔD, 1 (Pb/Tb) - (Pa, /T1 mouth・(\(/
It, )−(14)x=−value I((:,,・DIT(
1) l-[zn(Bx/Bo,)-+4J,-I(Ph
4b)-(Pl, Ir, ) l-(M/R)-0J・
...(15) However, in FIG.
Therefore, this time t.

The value Iε of the voltage E of the second output signal 6a at r. ,and.

At time t, the masonry force signal 18a represents the pressure P of the claw body 12, and the time t, the temperature signal 1
The value ra of the absolute temperature T of the gas 12 represented by 9a is stored, and furthermore, at the above-mentioned time t, the processing unit 2o/C second control 1 is stored.
1111 signal 20F); Since it is input, this place r3K・571) y Fertilize in advance! ia leta h- (Iro each of the above-mentioned physical iitUm, U'1
Representing pressure Pn value Pb and one time t.

(The value of @IfT that temperature signal 19a is afraid of is 'rb.

A? Each stored value E0□, P in the processing unit 20 mentioned above.

and T1 to perform the calculation on the right side (15) and output a spinning signal 20C as a thickness signal representing (L5) X on the left side as the result of this compensation. There is.

Therefore, the thickness gauge 17 (according to the thickness signal 20CrC
It is possible to accurately measure +9 [X
W: voltage value E, 1. After being told to memorize the pressure value P□ and the temperature fiTa, the change over time of the density IfD□ of the gas 12 (based on the thickness signal 2 which compensated for the measurement error described above) is continuously recorded.
It is clear from the above that 0C can be obtained, so it is very easy to carry out accurate thickness measurements at all times. In the case of 1117, all of them require N19 troublesome work.1 line insertion 2. source container 43. radiation detector 4 and bulb 11a/pro. (Use pressure gauge 18, thermometer 19, and hair (therefore, ′γ
Thickness is 17 in total. 1 Thickness is 13 in total.
It is clear that the value Iay is greater than the value Iay, so the configuration of the thickness gauge 17 makes it extremely easy to manufacture and maintain the thickness gauge. .

Figure 2 is a block diagram of the 0-radial thickness gauge 21 as an embodiment different from the elliptical example shown in Figure 1 (shown in Figure 1) according to Wood Invention 9;
'+ in Figure 1 is that the pressure signal 18a and the temperature signal 19a are input, and - the first restraint signal 20a is input at the above-mentioned time 1t. Pressure value Pa and time 1. At this point, remember that the a #c signal 19a represents a, and the second control signal 2 is input at the above-mentioned time 1. Using the pressure value Pb, the time [, - the temperature value TI represented by the stop signal 192, and each of the above-mentioned sets Ta4i:jIVPa and Ta, (14)
The eleventh processing unit 22 performs the calculation on the right side and outputs the quality change signal 22a representing ΔDa of the calculation result, the second detection signal 61 and the density change signal 22a are input, and the second detection signal 61 and the density change signal 22a are inputted, and By inputting the first control signal 20a, the voltage value goa of the detection signal 6a at this time E1 is stored, and by inputting the second control signal 20b at the time E1, the voltage value goa of the detection signal 6a at this time E1 is stored. The voltage value Ex of the signal 6a at
and the amount of density change lD represented by the signal 22a after time 1
The second signal processing unit 23 performs the calculation on the right side (10) using a and the thickness value Eoa and outputs a thickness signal 231 representing the calculation result X, which performs the signal processing shown in FIG. Part 20
(By providing the thickness gauge 21, it is possible to accurately measure the thickness X of the object to be measured 11 using the signal 23m. It is obvious that maintenance is easy (there is no need to explain it).

〔Effect of the invention〕

As mentioned above (in the present invention).

Radiation source and the given rectangular distance G to this radiation source? a radiation detector that detects a radiation source (radiation source) and transmits first detection information corresponding to the detected radiation in step 11; Said first
A preamplifier outputs the detected signal as a 14 voltage signal (modified and sensitized to a 2S:15 signal having a voltage E proportional to the dose).

A pressure gauge that detects the side P of the gas in the fixed space and outputs a pressure signal representing the pressure P, and a temperature signal that outputs the absolute temperature T of the gas in the clear space and represents the absolute temperature T. The first control signal is input at time [1] when the H2 meter that outputs the second detection signal, the pressure signal, and the temperature signal are input, and the object to be measured is not inserted into the measurement space. The value EI, a of the voltage E of the second ejection signal at time 1, the value P3 of the pressure P represented by the pressure signal at time t1, and the value of the absolute temperature T represented by the Mlf signal at time [, Ta and the second control signal is input at time 1, which is later than time t1, so that time t!
The value Ex of the voltage E of the second run-in signal at and the time [.

Using the pressure signal Pb expressed by the pressure Pb and the temperature [8 vs.
A signal processing section 1 performs the calculation on the right side of Equation 11 and outputs a 4-square signal representing the calculation result 7'2X.
Therefore, it is a radiation thickness meter that measures the thickness X of a measured object inserted into a measurement space, where /c.

U! ! I is the absorption coefficient of the object to be measured for the radiation.

DIn is the density of the object to be measured.

U2 is the absorption coefficient of the gas for Komagumi radiation.

M is the molecular bond of both gases.

R is the universal gas constant.

This constitutes a radiation thickness meter.

x=-(1/(UIl, @D-)l・Ctn (E
/B 0a)+U a・((Pb/Tb) (Pa/
Ta)I・(ru'R)-G:l・-・-・(1)Also 2
In the ninth aspect of the present invention.

A radiation source, and a first detection device that is arranged opposite to this radiation source via a measurement space having a predetermined leakage G, and detects the radiation emitted by the radiation source, and detects the radiation dose according to the detected radiation dose. a radiation detector that outputs a signal, a preamplifier that converts the first detection signal into a voltage signal and applies pressure as a second detection signal having a voltage E proportional to a pressure gauge that detects the pressure P of the gas at and outputs a pressure signal representing the pressure P, and a greenhouse meter that detects the sugar versus temperature T of the gas at nine measurement locations and outputs a temperature signal representing the absolute temperature T. 2. The pressure signal and the temperature signal are input, and the first control signal is input at the time [, when the object to be measured is inserted into the measurement space], so that the pressure P represented by the pressure signal at the time [1] is inputted. The value Ta of the absolute temperature T at which the temperature signal at the value P and time ! is clear
and time 1. By inputting the second control signal at a time later than , the value Pb of pressure P represented by the pressure signal at time tt, the value Tb of absolute temperature T represented by the temperature signal at time tt, and each of the above-mentioned stored values (2) Perform the calculation on the right side using the sounds P and Ta, and calculate Δ of this calculation result.
a first signal processing unit that outputs a density change signal representing Da;
The second detection signal and the density change signal are input, and the time 1
By inputting the first fllJ control signal at
shi, y + tsu time [, second system - word tsu tsu manpower, 7'
It's time for the second training signal at S.
Value Ex of E and time t! From now on, using the @notation ΔDa expressed by the compact #1 and the above-mentioned ji direct E0a (calculate the right side of equation 31 and output the thickness signal representing X of X d Samurai 14: A radiation thickness meter for measuring the thickness X of the inserted object (a radiation thickness meter for measuring the thickness X of the inserted object).

M is the molecular weight of the gas.

R2 is the universal gas constant.

Urn is the absorption coefficient of the object to be measured for the radiation; D is the density of the object to be measured.

U, is the radiation lIi! of the gas. absorption coefficient for,
This constitutes a radiation thickness gauge.

ΔD,={(Pb/Tb3-CP,/T(1)l・(M
/R)...(2)x=-(1/(Um'Dm)
)・[tn(Ex/Eoa)−+−U,・ΔD,・G)
(3) Furthermore, according to the present invention, a 4° radiation@original and this radiation source (with a predetermined interval G) are arranged opposite to each other with a space between them. Starvation radiation #source is 1M
A radiation detector that detects the radiation @1'l and presses the first detection signal in response to the conventional radiation resistance @labor, and the first detection signal is revised and increased. The radiation 111 of the target Ij treasure inserted into the measurement space in the radiation detection unit equipped with an amplifier that uses the voltage E as a second detection signal to generate the voltage E as a second detection signal. Absorption coefficient U for 9. and a first step of elongating the density YDm of the object to be measured and the absorption coefficient Ua of the air in the measurement space for the radiation to obtain the respective measured values.

Time 1 when the object to be measured is not inserted into the measurement space n. 1 direct E of the voltage E of the second detection signal. a
At the same time, the pressure P of the gas in the measurement cavity at 1 time (violet) is memorized, the pressure value Pa of the measurement result is memorized, and the absolute temperature of the gas in the measurement cavity at time t1, IfT, is measured. The third method is to store the temperature value Ta of the measurement result.

Chikari 1. At a later time t, the value Ex of the voltage E of the second detection signal by 5% is stored, and the pressure P of the gas in the measurement space at the time is measured and the pressure value Pb of the measurement result is stored. a third step of measuring the absolute temperature T of the gas in the measurement space at the specified time and storing the temperature value Tb of the measurement result;

Each of the stored values Um stored in the first to third steps.

Dm, U3 * B 03 , P3, Ta * EX
, Pi) and TI), and the fourth step of calculating the right-hand side of Equation 11.
This is a thickness measurement method using radiation in which X on the left side is the measured value of the thickness of the object to be measured.

Uo is the absorption coefficient of the object to be measured for the radiation 9.

Do is the density of the object to be measured.

Ua is the absorption coefficient of the gas for the radiation (M) is the molecular weight of the gas.

R is the universal gas constant We constructed a thickness measurement method using radiation as follows.

X= +t/(Um-Dm)+-[zrt(Ex/E
oa)+U, *f<F"b/Tb)-(F'a/Ta)
l-(M/R)-G)...- (1) Therefore, if we construct it as shown below, we can obtain +112〇- from Equation C) and Equation (3). This is obvious, and as mentioned above, σ)2 is an equation that takes into account changes in the gas density '1t-Da in the measurement space of the turtle pressure sumi Eo in equation 6). According to the present invention, the above-mentioned radiation source 2, source container 3, radiation detector 4, and amplifier 6, each of which requires a laborious task to manufacture, can be proved as follows. Radiation detection section 15 is not required.

By using a pressure gauge and a thermometer that detect the pressure and temperature of the gas in place of the detection unit 15, the configuration of the thickness gauge can be simplified.

In conclusion, the VC of the present invention has the advantage that the thickness gauge can be manufactured and maintained easily.

[Brief explanation of drawings]

FIG. 1 is a block diagram of one implementation of the radiation thickness meter based on the present invention 1jJ]fC. Figure 2 is a W4 diagram of a leprosy case different from the actual example shown in Figure 1 of the radiation thickness gauge according to the present invention. Figure 3 is a value I diagram of a conventional radiation edge thickness gauge. Figure 4 shows the beak of a conventional radiation/thickness meter that is different from the radiation collar modest eaves shown in Figure 3. 1, 13.17.21...Radiation thickness meter , 2・
...Radiation 11[, 2a...Radiation, 4.
...Radiation detector, 4a...First detection signal, 5.14...Measurement space, 6...Preamplifier, 5a...Second detection Signal, 9.15・
...-Radiation detector, 10.16.20...
---Signal processing section, 10al 20CI231...
... Thickness signal, 11 ... Measured object, 12
······gas. 18...Pressure gauge, 181...Pressure signal, 19...Thermometer. 19m...1 odd signal, 20a...1st
Control signal, 20b...Second control signal, 22...
. . . 1st signal processing section, 22a . . . Density change signal, 23 . . . 2nd signal processing section.

Claims (1)

[Claims] (1) A radiation source and a predetermined distance G with respect to this radiation source
radiation detectors that are arranged opposite to each other with a measurement space having a preamplifier that converts into a voltage signal, amplifies it, and outputs it as a second detection signal having a voltage E proportional to the dose; and a preamplifier that detects the pressure P of the gas in the measurement cavity and outputs a pressure signal representing the pressure P. a pressure gauge that detects the absolute temperature T of the gas in the measurement cavity and outputs a temperature signal representing the absolute temperature T;
The second detection signal, the pressure signal, and the temperature signal are input, and the first control signal is input at time t_1 when the object to be measured is not inserted into the measurement space. The value E_0_a of the voltage E of the second detection signal at time t_1, the value P_a of the pressure P represented by the pressure signal at time t_1, and the time t.
The value T of the absolute temperature T represented by the temperature signal at _1
_a, and a time t later than the time t_1.
By inputting the second control signal at _2, the value E_ of the voltage E of the second detection signal at the time t_2
x, the value P_b of the pressure P represented by the pressure signal at time t_2, the value T_b of the absolute temperature T represented by the temperature signal at time t_2, and each of the stored values E_0.
_a, P_a and T_a to calculate the right side of equation (1) and output a thickness signal representing x of the calculation result, A radiation thickness meter for measuring the thickness x of the object to be measured inserted into the object, where U_m is an absorption coefficient of the object to be measured for the radiation. D_m is the density of the object to be measured; U_a is the absorption coefficient of the gas for the radiation; M is the molecular weight of the gas; and R is a universal gas constant. X=-{1/(U_m・D_m)}・[ln(E_x/
E_0_a)+U_a・{(P_b/T_b)−(P_
a/T_a)}・(M/R)・G]... (1) 2) A radiation source and a radiation source arranged opposite to the radiation source through a measurement space having a predetermined interval G, and the radiation source is a radiation detector that detects emitted radiation and outputs a first detection signal according to the dose of the detected radiation; and a radiation detector that converts the first detection signal into a voltage signal and amplifies it to a voltage E proportional to the dose. a preamplifier that outputs a second detection signal having a pressure P of the gas in the measurement cavity and a pressure gauge that outputs a pressure signal representing the pressure P; and an absolute temperature T of the gas in the measurement cavity. at time t_1 in a state where the pressure signal and the temperature signal are inputted, and the object to be measured is not inserted into the measurement space. 1st
By inputting a control signal, the value P_a of the pressure P represented by the pressure signal at the time t_1 and the value T_a of the absolute temperature T represented by the temperature signal at the time t_1 are stored, and from the time t_1 By inputting the second control signal at a later time t_2, the value P_b of the pressure P represented by the pressure signal at the time t_2 and the value T_b of the absolute temperature T represented by the temperature signal at the time t_2. and each of the stored values P_a and T
a first signal processing unit that performs the calculation on the right side of equation (2) using _a and outputs a density change signal representing the calculation result ΔD_a; the second detection signal and the density change signal are input; By inputting the first control signal at the time t_1, the value E_0_a of the voltage E of the second detection signal at the time t_1 is stored, and the second control signal is input at the time t_2. Equation (3) is calculated using the value E_x of the voltage E of the second detection signal at the time t_2 by being input, the ΔD_a represented by the density change signal after the time t_2, and the stored value E_0_a. a second signal processing unit that performs a calculation on the right side and outputs a thickness signal representing x of the calculation result, and the thickness of the object to be measured inserted into the measurement space is determined by the thickness signal. A radiation thickness meter that measures x, where M is the molecular weight of the gas, R is the universal gas constant, U_m is the absorption coefficient of the object to be measured for the radiation, D_m is the density of the object to be measured, A radiation thickness meter characterized in that U_a is an absorption coefficient of the gas for the radiation. ΔD_a={(P_b/T_b)−(P_a/T_a)
}・(M/R)...(2)x=-{1/(U_m・D_m
)}・(ln(E_x/E_0_a)+U_a・ΔD_
a・G}...(3) 3) A radiation source and a radiation source that is electrically distributed across the radiation source through a measurement space having a predetermined interlayer G and that detects the radiation emitted by the radiation source. a radiation detector that outputs a first detection signal according to the radiation dose; and a radiation detector that converts the first detection signal into a voltage signal, amplifies it, and outputs it as a second detection signal having a voltage E proportional to the dose. an absorption coefficient U_m for the radiation of the object to be measured inserted into the measurement space in a radiation detection unit equipped with a preamplifier, a density D_m of the object to be measured, and an absorption coefficient U_a of the gas for the radiation in the measurement space; a first step of measuring and storing each measured value; and a value E_0_a of the voltage E of the second detection signal at time t_1 when the object to be measured is not inserted into the measurement space. At the same time, the time t_
Measure the pressure P of the gas in the measurement space at t_1 and store the pressure value P_a of the measurement result, and at the time t_1.
a third step of measuring the absolute temperature T of the gas in the measurement space and storing the temperature value T_a of the measurement result; and the second step at a time t_2 later than the time t_1.
The value E_x of the voltage E of the detection signal is stored, and the pressure P of the gas in the measurement space at the time t_2 is measured and the pressure value P_b of the measurement result is stored, and the measurement at the time t_2 is performed. A third device that measures the absolute temperature T of the gas in the void and stores the temperature value T_b of the measurement result.
procedure, and each of the stored values U_m. stored in the first to third procedures.
D_m・U_a・E_0_a・P_a・T_a・E_x
- A fourth step of calculating the right side of equation (1) using P_b and T_b, and x on the left side of equation (1) as the calculation result of the fourth step is used to measure the thickness of the object to be measured. A thickness measurement method using radiation with a value of U
_m is an absorption coefficient of the object to be measured for the radiation, D_m is the density of the object to be measured, U_a is an absorption coefficient of the gas for the radiation, M is the molecular weight of the gas, and R is a universal gas constant. A thickness measurement method using radiation. X=-{1/(U_m・D_m)}・[ln(E_x/
E_0_a)+Ua・{(P_b/T_b)−(P_a
/T_a)}・(M/R)・G〕……(1)