The Transverse-Field Silicon Detector

It has been our experience during the past few years that LiD silicon detectors can be produced with depths up to not more than 7mm on a production basis and up to about double this depth as a laboratory project. With the installation of several machines producing protons of energies in excess of 50MeV, standard SiLiD detectors with depths to 5mm became unable to provide energy-linear signals for many experiments. Further, deeper detectors present problems due to their higher voltages of operation and to the long transit time for carriers produced by the ionizing radiation. This paper describes a new form of LiD silicon detector which combines the advantages of large sensitive depth (25mm), thin window (less than 0.5 micron) and rapid sweep-out (less than 50nS). Construction details are given. The device is arranged so that the direction of field produced by detector bias is at right angles to the line of flight of experimental particles. A protected thin wind. ow is obtained by a silicon oxide process; active areas up to 200mm2 are achieved by use of two wafers, produced by the diffused-contact process, and placed face-to-face. Resolutions for medium energy protons have now been achieved of small fractions of one per cent. The device gives total energy measurements on alphas up to 20nMeV, protons to 80MeV. The paper describes the significant process details together with some parameter measurements.