Patent GB-711527-A (GB)
Title: Automatic counting apparatus
IPC: G01R23/10
Filed: 1952-06-26
Abstract: 711,527. Pulse metering. NATIONAL RESEARCH COUNCIL. June 26,1952, [June 29,1951.] No. 16126/52. Class 37,. Apparatus for automatically recording the results of a count of electric pulses occurring irregularly, e.g. from a radio-active source, can be arranged to count the pulses arriving during a predetermined period, or the time for a given number of pulses, with an overriding time limiter if the pulse rate is low. For determining the pulses in a given time, a counter 38 (Fig. I) is connected via switch 36 to a source of timing pulses 37 and controls a motor 39 capable of driving a time interval printing mechanism 35. The pulses from a source 30 are fed via a switch 31 to a scaler 32 which, for every N pulse received sends out one pulse to operate a print stamper 34. At the beginning of a count the motor 39 is disconnected from the printing wheels of stamper 34, so that the stamper prints a row of zeros for each pulse received from scaler 32: at the end of the predetermined period the counter 3<SP>8</SP> couples motor 39 to the print stamper 34, and the scaler 32 to a complementary source of pulses 33 operating at a known, constant rate. Receipt of the next pulse from the scaler 32 causes the print stamper 34 to stamp the time during which complementary pulses were sent, and the apparatus is reset to normal, initial conditions. Hence the markings of the print stamper 34 tell the total pulses received from the scaler 32, and for what time the pulses from source 30 were augmented by pulses from the complementer 33. For determining the time for a given number of pulses, the scaler 32 is connected via switch 36 to the counter 38, whereby pulses from 32 cause the print stamper 34 to indicate the time of each received pulse until 38 stops and resets the mechanism when it has received its predetermined number of pulses. If the pulse rate is low an override time control 40 operates after a predetermined time to cause print stamper 34 to print the time, and switches scaler 32 to the complementer 33. At the next pulse from the scaler the time is printed and the apparatus resets. The choice of the type of count is made by manual switching, and details of the relay circuits for each type are given. The pulse source may operate through a pulse amplitude analyser which may be automatically operated to select pulses of any predetermined amplitude interval. The timing pulse source 37 consists of a synchronous motor driving a cam-operated switch Fig. 5, (not shown). The complementer unit 33 Fig. 8, (not shown), comprises a synchronous motor driving a slotted scanning disc interrupting a light beam to a photocell. The pulses are amplified, and differentiated before being made to trigger a thyratron to give a positive or negative pulse as required. Interchangeable scanning discs provide for different pulse rates. The recycling unit 30 Fig. 9, (not shown) includes a turntable containing several samples which are automatically presented to a geiger counter in sequence, and a series of motordriven cam-operated switches which time the sequence of relay operations.