Professor Tony Weidberg

Abstract:

The two-jet invariant mass spectrum as measured in the UA2 experiment is used to search for additional heavy vector bosons decaying to two-jets. The mass of an additional W boson that couples to fermions with a V+A form is constrained to be greater than 261 GeV to the 90% confidence level. A limit on the production cross section of additional W and Z bosons is given as a function of the boson mass. A limit on the production of excited quarks is also given as a function of the excited quark mass. © 1993.

Abstract:

An analog memory array with 64 memory cells for each channel has been designed and manufactured in CMOS. A new skip logic controller allows to write at 66 MHz without dead time and to read out at a lower frequency simultaneously. The input circuit is charge-sensitive and integrates continuously. Pedestal nonuniformity is 1.4 mV rms from cell-to-cell and 3.5 mV rms between channels. The linearity range is -2.5 to +1.5 V, which corresponds to 11 bits. The chip has been used in a particle detection test. © 1993.

Abstract:

We report measurements of the behaviour of silicon diodes when exposed to integrated neutron doses of up to 5 × 1013 neutron/cm2. The measurements have been made at diode temperatures between room temperature and -20°C. From measurements of the diode leakage current and depletion voltage, and consequent evaluations of the effective impurity concentration, the temperature dependence of these quantities is discussed in terms of the annealing behaviour of the diodes. Comments are made on the suitability of silicon as a detector medium for particle physics experiments at future accelerators. © 1993.