SU458793A1 - Radiometric device - Google Patents

Description

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The invention relates to the field of experimental nuclear physics.

A radiometer is known that includes a radiation detector, an amplifying path, a differential discriminator, and an intensity meter. Electromagnetic interference arising in any of the blocks located before the discriminator or in the discriminator itself, and the useful signal is already normalized in amplitude and duration to the delay line and then to the one-time measurement time of the instantaneous pulse frequency, having a dwell time longer than the period of damped sinusoidal oscillation . If during the exposure time of this one-shot the discriminator leaves at least one more pulse of the useful signal or interference, the signal-inhibiting circuit blocks the signal from flowing to the intensity meter for the duration of the inhibit one-shot.

The disadvantages of the blocking scheme in the known device include:

1) the prohibition of registration in this device is carried out not for the duration of the interference, but for a fixed time interval determined by the holding time of the one-shot prohibition. This leads to an increase in the error of registration of useful signals, since, for noise durations less than

the holding time of the one-shot prohibition; blocking of the useful signals that have fallen to the input of the circuit during the holding time of this one-shot;

2) the blocking device does not allow blocking those interference pulses, the period of which is longer than the one-time exposure time of the one-time measurement of the instantaneous frequency of the signals;

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3) the device has a limited frequency range of registration of useful signals in the presence of interference, since the presence of a fixed exposure time of the one-preta single-vibrator leads to an increase in the error in transmitting useful signals even if the duration of the interference is much less than the exposure time of this single-oscillator and useful signals are comparable. In order to increase

0 measurement accuracy and speed increase, the device contains a blocking block of electromagnetic interference, consisting of serially connected converters of instantaneous pulse frequency in

5 is a control signal and a Schmitt trigger, the output of which is connected to the control input of the inhibiting circuit, the second input of which is connected to the output of the amplitude selector through a delay unit. In addition, the trigger outputs

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Schmitt and the prohibition circuit are connected to a discharge unit, the output of which is connected to the input of an instantaneous pulse frequency converter into a control signal.

The drawing shows a block diagram of the device described, comprising: ionizing radiation detector 1, linear amplifier 2, amplitude selector 3 with output signals normalized in amplitude and duration, blocking interference 4, consisting of a converter of instantaneous pulse frequency 5 into a control signal , delay unit 6, Schmitt trigger 7, prohibition scheme 8, bit unit 9, recorder 10.

The device works as follows.

In the absence of electromagnetic interference, when registering useful signals from detector 1, the signals after amplification in amplifier 2 and amplitude selection in block 3 are normalized in amplitude and duration to the input of the instantaneous frequency converter of the input signals to the control signal and input of the delay block 6 of the blocking blocking block 4 In the instantaneous frequency converter 5, which is an integrating circuit with a dosing capacity, each input pulse charges the charging capacitance to a potential UQ which is insufficient to operate. an Schmitt trigger. 7. The discharge of the integrating capacitance occurs with a constant time, shorter than the period of the useful signals. A pulse from the output of the delay unit 6, which has a dwell time longer than the period of impulses in the disturbance, and made in the form of a one-shot, passes a normally open prohibition circuit 8 for the passage of signals to the recorder 5. Simultaneously, the pulse from the output of the prohibition circuit 8 through the discharge unit 9 discharges the integrating capacitance of the converter 5 to the original potential.

When exposed to the transmission path of useful signals, electromagnetic interference, representing or damped sinusoidal oscillations with a period shorter than the period of arrival of useful signals, or a sequence of bursts of pulses with a mean frequency in the pack is greater than the average frequency of the recorded signals, each pulse of interference after amplification and normalization in block 3, it charges the charge capacitance of the integrating circuit by t / o. Thus, the second interference pulse already causes an increase in the potential of the charge capacitance to a value sufficient to trigger the Schmitt trigger 7, the pulse of which blocks through the control input of the inhibitor circuit 8 the pulse from the output of the delay block 6 to the recorder 5. The trigger Schmitt trigger 7 will occur when the charge capacitance of the instantaneous frequency converter 5 is discharged to the release potential of the Schmitt trigger 7. If

the time constant of the discharge of the charge capacitance is calculated in such a way that the potential on the charge capacitance of the converter 5 does not change significantly during the period of arrival of the pulses, and the charge capacitance of the Schmitt trigger determines the time of the arrival of useful signals. interference. To increase the speed of the circuit, the pulse corresponding to the moment of release

the Schmitt trigger and the end of the interference, through the discharge unit 9, discharges the charging capacitance of the converter 5 to the initial potential. Thus, the blocking time in this device is determined by the duration of the interference, which is allocated on the instantaneous frequency converter of the output pulses to the control signal and recorded with the Schmitt trigger, the recovery time of which is minimal.

Subject invention

Claims (2)

1. A radiometric device comprising an ionizing radiation detector, a linear amplifier, an amplitude selector and a recorder, characterized in that, in order to improve the measurement accuracy, between the output of the amplitude selector and the input The recorder includes an EMI blocking block consisting of a series-connected instantaneous pulse frequency converter into a control signal and a Schmitt trigger whose output is connected to the control input of the inhibitor circuit, the second input of which is connected to the output of the amplitude selector through a delay unit. 2. The radiometric device according to claim 1, characterized in that, in order to increase speed, the Schmitt trigger and inhibit circuit outputs are connected to a discharge unit, the output of which is connected to the input of the instantaneous frequency converter pulses in the control signal. I