H.R. Shaylor

A fast on-line trigger for events with multiple high transverse momentum tracks

Abstract We present a fast (30 μs) on-line trigger that selects, from 300 GeV/ c π − interactions, events with three tracks of transverse momentum larger than 0.9 GeV/ c . The essential features of this trigger are a fast read-out (300 ns per cluster) of wire chambers, situated on the chamber frame, and a digital computation of transverse momenta that can cope with multiple hits in the detectors of the trigger tracks. The digital computation is done with standard MBNIM modules.

Irradiation studies of multimode optical fibres for use in ATLAS front end links

The radiation tolerance of three multimode optical fibres has been investigated to establish their suitability for the use in the front-end data links of the ATLAS experiment. Both gamma and neutro ...

Use of silicon microstrip detectors for precise measurement of high momenta

Abstract The WA76 experiment performed at the Ω facility at CERN required a high precision measurement of the forward produced particle whose momentum was close to 300 GeV/c. A telescope made of 12 silicon microstrip detectors has been built and operated for such a purpose.

System tests of radiation hard optical links for the ATLAS semiconductor tracker

A prototype optical data and Timing Trigger and Control transmission system based on LEDs and PIN-diodes has been constructed. The system would be suitable in terms of radiation hardness and radiat ...

ATLAS beam test results

Abstract Many different configurations of electronics and semiconductor strip detectors were studied in 1995 using the ATLAS tracking detector test area at the H8 beam-line of the CERN SPS. A significant fraction of these investigations are presented elsewhere in this volume and this paper will concentrate on the results with silicon strip detectors read out with electronics preserving the pulse height information. Data has been collected with the ADAM, APV5 and FElix read-out chips on a number of different detectors. The first results are presented for read out with LHC electronics of detectors to the ATLAS-A specification of 112.5 μm pitch, employing n-strips in n-type silicon, capacitive coupling and intermediate strips. It is demonstrated that with adequate signal/noise, a spatial resolution of ⋍13 μm is attainable with these detectors.

A spin-parity analysis of the f1(1285) and f1(1420) mesons centrally produced in the reaction pp→pf(KS0K±π∓)ps at 300 GeV/c

Abstract Results are presented of an analysis of the reaction pp→p f (K S 0 K ± π ∓ )p s at 300 GeV/ c . Clear f 1 (1285) and f 1 (1420) signals are seen. A spin-parity analysis shows that both are consistent with being 1 ++ states. The f 1 (1420) is found to decay only to K ∗ K and no 0 −+ or 1 +− waves are required to describe the data. The production of the f 1 (1285) as a function of energy is not the same as that for the f 1 (1420) whose cross section is found to be constant with energy.

Irradiation tests of optoelectronic components for LHC inner-detectors

Abstract Two kinds of optical-link technologies have been investigated for the readout of data at LHC experiments; one based on LEDs and the other on Multi-Quantum-Well modulators. Presented in this paper are the results of irradiating LEDs and MQW modulators with 1 MeV-equivalent neutrons and 24 GeV protons. The devices were biased and the performances of the optical links were monitored throughout the tests. The fluences achieved were ∼ 5 × 10 14 n cm −2 and ∼ 6 × 10 13 p cm −2 .

Direct ϱ0 production at large pT

Abstract The production of ϱ 0 mesons in hadronic interactions is investigated at high transverse momentum (p T > 2 GeV/c). The data come from a sample of π-N interactions at 300 GeV/c obtained at the CERN Omega Spectrometer, requiring at ϱ 0 → π + π − with p T (pair) > 2 GeV/c to recoil against an opposite particle with p T (opposite) > 1 GeV/c. The signal/(signal + background) ratio of ϱ 0 production shows an increase of 38% as ξ E = p T (opposite)/p T (pair) decreases from 0.5 ξ E ξ E ⩽ 0.5. This increase is not compatible with a QCD model of parton scattering and subsequent fragmentation, and gives a strong indication that direct ϱ 0 production has been observed. Data has now been taken at 150 GeV/c and additional signatures to be used to identify direct ϱ 0 production are discussed.