Dick A. Mack

Test routines and monitoring for a large counter experiment

Abstract Some recent multichannel scintillation-counter experiments are so complex that the use of test routines and fault monitoring becomes essential. In a recent experiment, it was desired to initially align the system, provide continuous calibration during the experiment, and rapidly locate the cause of threshold drift or catastrophic failure. A test and monitoring system was devised in which synthesized pulses are injected into several points of the system, and the operation is automatically compared with the desired response. If the system performance does not agree within prescribed limits, an alarm sounds. Through a program that varies the amplitude of the test signal, one can check coincidence-circuit threshold and feed-through characteristics. By programming delay between input pulses, the resolving time can be measured. Several novel monitoring devices have been developed which allow one to assess the display of a large volume of information at a glance. One unit for reading time delays involves the use of a cathode-ray-tube raster display, another unit for reading binary information employs a transistor-driven incandescent lamp panel.

An electronic data-acquisition system for use with a complex nuclear physics experiment

Abstract An electronic data-acquisition system is used with a nuclear physics experiment of such complexity that data processing required a high-speed computer. The system acquires data from 168 signal channels of scintillation counters and four channels of chronotron circuits. It has the capacity to store 10 events during the 0.1-sec-long Bevatron beam pulse. The storage time for the information from each event, consisting of 168 bits from the counters plus 12 bits from the chronotrons, is 40μsec. In the interval between beam pulses, the stored information is punched onto paper tape in a form suitable for computer input. This report describes the over-all characteristics and operation of the system. The specific parts of the system and techniques for semi-automatic testing are given in the companion reports.

Beam-Profile Indicator

This paper describes an instrument for displaying intensity profiles of charged-particle beams that emerge from high-energy accelerators. The intensity vs position on a strip of 21 scintillation counters each 1 by 1 cm appears as a histogram on an oscilloscope. The display is accomplished by employing transistor circuits to amplify and integrate the outputs of the multiplier phototubes. The accumulated charge associated with each counter element is then read out in sequence by means of a blocking-oscillator commutator. The output signal is further amplified logarithmically for oscilloscope deflection.

Direct-View Vidicon Scanning System for Spark Chambers

A vidicon camera tube furnishes an ideal means for directly viewing spark-chamber events. By digitizing spark locations initially, one can perform the subsequent circuit logic by digital-circuit techniques. Information stored on magnetic tape can be presented in a format suitable for immediate analysis by a computer. A recent system for scanning two views of 12 spark-chamber gaps is described along with plans for future developments.