F. Sannes

Particle‐ and photoinduced conductivity in type‐IIa diamonds

Electrical characteristics associated with radiation detection were measured on single‐crystal natural type‐IIa diamond using two techniques: charged particle‐induced conductivity and time‐resolved transient photoinduced conductivity. The two techniques complement each other: The charged particle‐induced conductivity technique measures the product of the carrier mobility μ and lifetime τ throughout the bulk of the material while the transient photoconductivity technique measures the carrier mobility and lifetime independently at the first few micrometers of the material surface. For each technique, the μτ product was determined by integration of the respective signals. The collection distance that a free carrier drifts in an electric field was extracted by each technique. As a result, a direct comparison of bulk and surface electrical properties was performed. The data from these two techniques are in agreement, indicating no difference in the electrical properties between the bulk and the surface of the ...

The CLEO detector

Abstract The construction and performance of a large aperture magnetic detector designed for use at the Cornell Electon Storage Ring is descr bed.

Evidence for hard scattering of hadronic constituents of photons in photon-photon collisions of TRISTAN

Abstract We present results of an experimental study of e + e − + hadrons in the kinematic regime for which the process is interpreted as hadron production in collisions of almost-real photons. The data sample corresponds to an integrated luminosity of 27.5 pb − and covers center-of-mass energies from 55 to 61.4 GeV. We observe more events than expected from the incoherent sum of quark-parton and vector-meson-dominance models, and we give a quantitative explanation of the excess by including the hard scattering of the hadronic constituents of the photons calculated with QCD.

Measurements of the inclusive jet cross section in photon-photon interactions at TRISTAN

Abstract We present cross section measurements for inclusive jet production in almost-real photon-photon interactions at TRISTAN using the AMY detector. The results are compared with leading-order QCD calculations for different parameterizations of the parton density in the photon.

A measurement of the photon structure function F2

Abstract The photon structure function F2 has been measured at average Q2 values of 73,160 and 390 ( GeV c ) 2 . We compare the x dependence of the Q2 = 73 ( GeV c ) 2 data with theoretical expectations based on QCD. In addition we present results on the Q2 evolution of the structure function for the intermediate x range (0.3⩽ x ⩽0.8). The results are consistent with QCD.

Nuclear size dependence of inclusive particle production

Abstract The inclusive production of π+, π−, K+, K−, p and p for protons incident on carbon and tungsten targets was studied at the Internal Target Area of the Fermilab. We assume an Aα dependence for the inclusive cross sections and report here on the variation of α with incident momentum, transverse momentum and particle species.

Performance of a diamond-tungsten sampling calorimeter

We report here the first measurements of a diamond-tungsten sampling calorimeter. The calorimeter consisted of twenty layers of diamond with one radiation length of tungsten per layer. The diamond layers were grown by chemical vapor deposition and were 3.0 × 3.0 cm2 wafers with an average thickness of 500 μm. We measured the energy response and resolution (σE/E) of this calorimeter in 0.5–5.0 GeV electron beams and compared the results with those from a silicon calorimeter of similar construction. Our energy resolution is σE/E = (4.7 ± 2.7)%/E≍(19.13±0.86)%/√E≍(2.3±1.8)% for the diamond-tungsten calorimeter, where ⊕ indicates addition in quadrature. This is in good agreement with our result for the silicon-tungsten calorimeter of σE/E = (3.89 ± 0.87)%/E ≍ (19.73±0.19)%/√E ≍(0.0 ± 1.6)%. We also compare our data with EGS simulations.

Measurement of αs from the moment of particle momenta within jets from e+e- annihilation

We present a study of the third moment of the inclusive momentum distribution of particles within jets produced by e+e- annihilation at TRISTAN. In this analysis, the QCD coupling strength alpha(s) is determined by fits to the prediction of the Next-to-Leading Logarithm Parton-Shower model. The measured value of alpha(s) (57.9 GeV) = 0.134(-0.005)+0.006.

A search for leptoquark and colored lepton pair production in e+e- annihilations at TRISTAN

Abstract We report on a search for the pair production of leptoquarks and colored leptons in e + e − annihilations t center-of-mass energies from 50 to 60.8 GeV, using the AMY detector at TRISTAN. No evidence for such particles is found and 95% CL mass limits are given.

Diamond detectors for high energy physics

We have constructed charged particle detectors using high quality CVD diamond. We report here the measurements of a diamond-tungsten sampling calorimeter and a diamond mustrip detector. The energy response and resolution (σEE) of the calorimeter were measured using an electron beam of energy 0.5 to 5.0 GeV, and compared with those from a silicon calorimeter of similar construction. We find σEE = (4.7 ± 2.7)%/E ⊕ (19.13 ± 0.86)%/√E ⊕ (2.3 ± 1.8)% for the diamond-tungsten calorimeter, where ⊕ indicates addition in quadrature, which is in good agreement with our result of σE/E = (3.89 ± 0.87)%/E ⊕ (19.73 ± 0.19)%/√E ⊕ (0.0 ± 1.6)% for the silicon-tungsten calorimeter. The CVD diamond mustrip detector consists of 50 μm wide strips on 100 μm centers. A signal-to-noise ratio of 6: 1 and a position resolution of 25 μm was observed during recent accelerator tests.