A. Alberigi Quaranta

Characterization of high resistivity CdTe for γ-ray detectors

Abstract This paper presents an extensive investigation on semi-insulating CdTe for use in radiation detectors. Transient techniques are used to measure the carrier drift mobilities and trapping times, the plasma time, and the activation energies, cross sections and densities of traps. A shallow electron trap with a density of 1017 cm−3, an activation energy of 0.05 ± 0.01 eV, and a cross section of 10−16 cm2 was identified. The electron trapping time increases by over an order of magnitude with increasing electric field. The plasma time for 5.48 MeV alpha particles ranged from 100 nsec at an electric field of 500 V/cm to 4 nsec at an electric field of 10 kV/cm. With 5.0 MeV alpha particles from an accelerator a room temperature resolution of 0.58% (fwhm) was obtained.

On the information available from the rise-time of the charge pulse supplied by semiconductor particle detectors

Abstract This paper shows that by measuring the collection time of the charge released in the depletion layer of a solid state radiation detector, some information can be obtained about the ionizing particle impact angle or about its range in the depletion layer. Several criteria are also given which allow for selecting the detectors suitable to obtain the above mentioned information.

Plasma time and related delay effects in solid state detectors

Abstract The initial delay in the response of surface barrier detectors to heavily ionizing particles is experimentally studied. Various experimental results are given about this delay in different detectors as a function of electric field and temperature. These results can be of particular interest in experiments requiring a time reference obtained by means of a solid state detector.

PROTON--DEUTERON DISCRIMINATION WITH A SINGLE SEMICONDUCTOR DETECTOR.

Abstract A novel method is presented which permits to discriminate protons from deuterons with a single surface barrier detector and a very simple electronic circuitry. The energy measurement is not influenced by the particle discrimination system.

Fast pulse pickoff with semiconductor radiation detectors

Abstract The problem is investigated of extracting a fast signal at the same time of the energy signal from a solid state detector. The effect of the charge amplifier on this waveform is accounted for. A new method is suggested for achieving fast timing with this kind of detectors.

A special system of proportional counters to be used as a high pressure gas target without walls

Abstract A special assembly of high pressure wire proportional counters is described. Their operation defines a volume in a gaseous target, the effective limits of which are set mainly by the electric fields of the counters and not by a continuous material wall. The apparatus, used in a recent experiment — at the CERN 600 MeV synchrocyclotron — while filled with extremely purified hydrogen, is fitted to work with any gas, or mixture of gases, proper to fill gas proportional counters. The device seems suitable to be used in different fields of high-energy physics.

SINGLE CHANNEL TRANSISTORIZED PULSE HEIGHT ANALYZER

Abstract A completely transistorized single channel pulse analyzer is described, with a dead time of 330 ns. The range on the pulses that may be analyzed is 0.3 ÷ 6V. The window width and the threshold voltage are independent and determined by the reverse bias of two distinct diodes. The complete circuit diagram is given with a series of tests obtained with several input pulse widths up to a frequency of 2 Mc/s and for room temperatures ranging from 10°C to 40°C.

On a fast sixteen channel analyser

Abstract A fast 16-channel pulse-height analyser fitted for use in high-energy physics experiments is described: its over-all dead-time is about 1 μsec. The circuit diagram and the performances of the analyser are reported.

ON A FAST TRANSISTORIZED PULSE AMPLIFIER

A fast transistorized pulse amplifier was developed with a large dynamic range and a good frequency overloading Some of the amplifier characteristics are: voltage gain = 4.9, risetime = 3.5 nsec max, and output pulse maximum amplitude (linearly amplified on 125-ohm cable) = --12 v. The amplifier is extremely stable. (D.L.C.)