PROGRAM-CONTROL DEVICE FOR THE PP-9-1 SCALING INSTRUMENT

P. S. ANANYIN

(Presented by the scientific-technical seminar of the High-Energy Laboratory of the Research Institute of Nuclear Physics)

In photographic recording of information from spark chambers for registering the parameters of the reaction under study (ionization losses, particle time of flight, etc.), the information is usually displayed on neon lamps located next to the spark chambers and photographed in a single frame. In this case it is necessary to use multicore cables and additional circuits to increase the brightness of the neon lamps. The use of PP-9-1 scaling instruments with program control solves this problem quite simply.

The scaling instrument (PP) operates according to the following program: the first start is performed by the operator; the indication scale is extinguished; with the arrival of a train of pulses from the BAP of the analyzer and its recording in the decades of the PP, the device is blocked at the input by the “stop” signal and the illumination of the indication scale is switched on; after exposure the readings in the decades are reset to zero by the “reset” pulse; after a certain time the “start” pulse prepares the scaling instrument to receive the next train.

Figure 1 shows the schematic diagram of program control of the PP-9-1 scaling instrument. It consists of three monostable multivibrators, pulse shapers, and a key circuit for controlling the illumination of the indication scale. The device is started by pulses from the shaper of the gating circuit of the BU-13 unit.

The first monostable multivibrator is assembled on \(T_2\), \(T_3\), and \(TD_1\); it generates the “stop” pulse \(65\,\mu\text{s}\) after the arrival of the first pulse of the train. The duration of the delay is determined by the maximum duration of the pulse train from the analyzer BAP (for AI-256—\(64\,\mu\text{s}\)). In order that the number of pulses in the train should not affect the delay time, the monostable multivibrator is blocked at the input by triode \(T_4\) through feedback \(R_{16}\). Triode \(T_4\) also plays the role of inverter and amplifier.

The “stop” pulse starts the second monostable multivibrator, assembled on triodes \(T_9\), \(T_{10}\), and \(TD_3\). It controls the key circuit for switching on the illumination of the indication scale, generates the “reset” pulse, and starts the third monostable multivibrator.

The key circuit for controlling the illumination of the indication scale is assembled on triodes \(T_{12}\), \(T_{13}\). The duration of the illumination is determined by the normal exposure of the PP readings on photographic film and is selected by the values of capacitors \(C_{12}\), \(C_{13}\), \(C_{14}\) (the circuit provides for two exposures, 400 and 700 ms).

To control the illumination of the indication scale, certain changes were made in the PP circuit: the power supply of the blocking generators of the illumination was fed through the key circuit. The changes in the circuit are shown in Fig. 2.

Fig. 1. Circuit diagram of the device.

Fig. 2. Changes in the circuit of units BP-20, BP-18.

The third one-shot multivibrator is assembled on triodes \(T_5\), \(T_6\) and \(TD_2\); it generates a “start” pulse 40 ms after the “reset” pulse. This delay is necessary for complete recovery of the circuit of the second one-shot multivibrator. The circuit provides for disabling the programmed-control device and for operation of the PP in the usual mode by means of toggle switch \(B_1\). To switch on constant illumination of the indication scale, toggle switch \(B_3\) is installed; it blocks the keying circuit. The circuit is powered from the PP power-supply unit.

Structurally, the control device is made as a separate unit on a free chassis of the counting instrument and is inserted into its housing. On the front panel there are a power-on toggle switch and an exposure-time switching toggle switch \(B_2\). The toggle switch for blocking the keying circuit, \(B_3\), is installed on the rear panel of the PP.

The author thanks V. N. Stepanov for participation in the manufacture and adjustment of the circuit.

REFERENCES

1. V. V. Klimov. A device with a controlled operating mode using tunnel diodes. In: Semiconductor Devices and Their Application. Edited by Ya. A. Fedotov, issue 14, “Sovetskoe radio,” 1965.

2. V. V. Klimov. Pulse shapers using tunnel diodes and transistors. In: Semiconductor Devices and Their Application. Edited by Ya. A. Fedotov, issue 22, “Sovetskoe radio,” 1969.

3. E. H. Hemanis. Formation of pulses using the charging and discharging of a capacitor through a tunnel diode. In: Automation and Computer Engineering. Issue 4, Publishing House of the Academy of Sciences of the Latvian SSR, 1963.

4. P. Heffner. A fast-recovery multivibrator using a tunnel diode. Electronics, 1964, No. 25.