JP2873244B2 - Integral digital rate meter - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an integrating digital rate meter used in radiological equipment and the like and displaying an input pulse value at a counting rate.

[Prior Art] Conventionally, an integrating digital rate meter used for a radiation measuring device in radiological medical equipment is known.
In this apparatus, a count rate value is calculated from a count value of input pulses within a preset time, and the count rate value is displayed on a display.

[Problems to be Solved by the Invention] Since the conventional integrating digital rate meter is configured as described above, if the set time is shortened when counting random pulses, the indicated value fluctuates due to statistical fluctuation. However, if the set time is increased to suppress the fluctuation of the indicated value, the interval at which the indicated value changes will be longer, and even if the count value changes, the indicated value will not change immediately. there were.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-described problems, and has as its object to obtain an integrating digital rate meter in which the statistical accuracy is improved over time and the indicated value is not largely changed.

Means for Solving the Problems An integrating digital rate meter according to the present invention includes a detector that detects an input pulse, an adder that integrates an output from the detector from the start of detection to the present, and a detector that starts detection. Counter that counts the time from the current time to the present, a divider that divides the integrated value integrated by the adder by the time from the start of detection when the counter counts to the present, and a display that displays the count rate value calculated by the divider And a container.

[Operation] The integrating digital rate meter according to the present invention detects the input pulse by the detector, integrates the output from the detector by the adder from the start of the detection to the present, and the counter measures the time from the start of the detection to the present. Is counted, and the integrated value accumulated by the adder by the divider is divided by the time from the start of the detection counted by the counter to the present time, and the counting rate value calculated by the divider is displayed on the display.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of an integrating digital rate meter according to the present invention. An integrating digital rate meter 10 is configured such that a low-pressure gas (such as alcohol vapor) is sealed in a metal tube and the central portion of the metal tube is closed. DC high voltage is applied between the and the tube wall, the radiation is detected as a discharge current by the ionization method and has a detector 12 for A / D conversion of the discharge current, and on the output side of the detector 12 Is connected to an amplifier 14 for amplifying the digital signal 100 output from the detector 12.

A counter 16 for counting the digital signal 101 amplified by the amplifier 14 is connected to the output side of the amplifier 14, and the output side of the counter 16 has a preset set time, that is, an interval time for displaying the count rate value. An adder 18 for integrating the count output from the counter 16 for each (Δt)
Is connected.

The sampling circuit 20 that sets an interval time (Δt) and outputs a timing pulse 102 at each interval time (Δt) is connected to the counter 16, and the counter 16 counts each time the timing pulse 102 is received. The count of the digital signal 101 is output and the digital signal 101 is reset by the output signal 103.

Further, a counter 22 for counting the timing pulse 102 output from the sampling circuit 20 at every interval time (Δt) is connected to the output side of the sampling circuit 20, and the output side of the counter 22 and the adder 18 is connected to the output side of the adder 18. After starting the count output from the adder 18 and starting the count by multiplying the total count 105 of the timing pulse 102 output from the counter 22 by the interval time (Δt) by the total count 105 up to the present. Time until now (T ₁ )
And a divider 24 for calculating the count rate value by dividing by.

The output side of the divider 24 is connected to a display 26 for displaying the count rate value calculated by the divider 24.

 Next, the operation of the present embodiment will be described.

When the radiation enters the detector 12, the low-pressure gas (alcohol vapor, etc.) sealed in the detector 12 is ionized and discharge occurs, and a discharge current flows instantaneously. This discharge current is A / D converted. Digital signal 100.

Then, the digital signal 100 is amplified by the amplifier 14, and the amplified digital signal 101 is counted by the counter 16.

At this time, the sampling circuit 20 outputs a timing pulse every preset time (interval time) (Δt).
The counter 16 receiving the timing pulse 102 outputs a count 103 of the digital signal 101 counted each time the timing pulse 102 is received to the adder 18 and is reset by the output signal 103.

Then, the adder 18 sequentially accumulates the count 103 output from the counter 16, and outputs the total count 105 from the start of counting to the present to the divider 24.

Further, the divider 24, which receives the total count 105 from the start of counting to the present time to the present, outputs the total count 105 from the counter 22 which counts the timing pulse 102 output from the sampling circuit 20. pulse
The count rate value is calculated by dividing the total count number 104 of 102 by the time (T ₁ ) from the start of counting by multiplying the total time by the interval time (Δt).

Then, the count rate value calculated by the divider 24 is displayed on the display 26.

For example, the display count rate (cps) after the first interval time (Δt) from the start of counting is R ₁ , and the total count 105 from the start of the count to the first interval time (Δt) is N _1. , The time from the start of counting to the first interval time (Δt) is T ₁ , the count of the i-th interval is n _i , and the interval time is Δt
Then Can be expressed as

Here, if Δt = 0.5 and i = 120, Is displayed on the display 26.

In the above embodiment, an ionization type detector has been described as a detector, but the present invention is not limited to the detector type.

[Effects of the Invention] As described above, according to the present invention, the count value obtained by dividing the integrated value obtained by the adder by the time from the start of detection to the present is displayed. When counting random pulses while maintaining the sensitivity of the indicated value due to the fluctuation, the fluctuation of the indicated value can be made smooth and the count rate value can be easily read.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an integrating digital rate meter according to the present invention. 10… Integrating digital rate meter 12… Detector 18… Adder 22… Counter 24… Divider 26 …… Display.

Continuation of the front page (72) Inventor Toshinori Oshima 22-1, Mutsu 6-chome, Mitaka-shi, Tokyo Aloka Co., Ltd. (56) References JP-A-57-206873 (JP, A) JP-A-62-24172 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) G01T 1/00-7/12

Claims (1)

(57) [Claims] 1. A detector for detecting an input pulse, an adder for integrating an output from the detector from the start of detection to the present,
A counter that counts the time from the start of detection to the present, a divider that divides the integrated value integrated by the adder by the time from the start of detection that the counter has counted to the present, and a counting rate value calculated by the divider. An integrating digital rate meter having a display for displaying.