Engineering topics
Publications and source records attributed to Humphreys, D. R..
A ten-channel analog switch has been developed as a sample and shape circuit for signals used as inputs to a logarithmic pulse height recording system. The circuit employs a field effect transistor as the switching element. Switching transients are reduced to approximately 2 mV by adding to the gated signal an inverted transient generated by an identical circuit with no signal applied. The circuit is linear to 2% from 3 mV to 10 V.
The longitudinal development of nuclear-electromagnetic cascades with energies greater than 200 GeV was measured in a low-Z (glass) absorber. This was done in the course of operating an ionization spectrometer at mountain altitude in an experiment to study the properties of gamma rays emitted from individual interactions at energies around 10,000 GeV. The ionization produced by a cascade is sampled by 20 sheets of plastic scintillator spaced uniformly in depth every 2.2 radiation lengths. Adjacent pairs of scintillators are viewed by photomultipliers which measure the mean ionization produced by an individual cascade in 10 layers each 1.1 interaction length (4.4 radiation lengths) thick. The longitudinal development of the cascades was measured for about 250 cascades having energies ranging from 200 GeV to 2500 GeV. The observations are compared with the predictions of calculations made for this specific spectrometer using a three-dimensional Monte Carlo model of the nuclear-electromagnetic cascade.
Gamma ray emission from individual interactions of hadrons in carbon at 10 TeV, using ionization spectrometer-emulsion chamber combination