C. Couyoumtzelis

Properties of photon plus two-jet events in {ovr p}p collisions at {radical}{ovr s}= 1.8 TeV.

We present the first general measurements (invariant-mass, transverse-energy, and angular distributions) of the process, {bar p}p{r_arrow}{gamma}+2 jets+X, using data collected by the CDF at Fermilab. We compare the data with predictions from a tree-level QCD calculation and the PYTHIA shower Monte Carlo program. Our data sample is particularly sensitive to contributions from initial- and final-state radiation of photons and jets. Using the PYTHIA Monte Carlo program, we contrast the kinematical distributions for direct photon production with those for initial- and final-state photon radiation (bremsstrahlung). Based on the angular distributions, we find that our data favor a mixture of bremsstrahlung and direct photon production, as predicted, over either process alone. {copyright} {ital 1997} {ital The American Physical Society}

Performance of the binary silicon system for ATLAS

We report on the results from a beam test of a binary silicon strip system proposed for ATLAS. The data were collected during the H8 beam test at CERN in 1995 and at a beam test at KEK in 1996. The binary modules tested had been assembled from silicon micro-strip detectors of different layout and from front-end electronics chips of different architecture. The efficiency, noise occupancy, and position resolution were determined as a function of the threshold setting for various bias voltages and angles of incidence. Interstrip effects were also evaluated using a high resolution telescope. The performance of a prototype detector module irradiated to a fiuence of 1.2 × 10 14 p/cm 2 is also characterized.

Pulse height of MIP's in an n-side silicon microstrip detector after proton irradiation with a fluence of 1x10**15 p cm**(-2)

We have irradiated an n-side silicon microstrip detector to an equivalent high energy fluence of 1/spl times/10/sup 15/ p cm/sup -2/ using 55 MeV protons. We determined the median pulse height to be 0.7 fC at a bias voltage of 180 V, and deduced a depletion region of about 80 /spl mu/m.