Construction and test of a fine-grained liquid argon preshower prototype

Abstract

A separate liquid argon preshower detector consisting of two l a y ers featuring a ne granularity of 2.5 10 3 was studied by the RD3 collaboration. A prototype covering approximately 0.8 in pseudo-rapidity and 9 degrees in azimuth was built and tested at CERN in July 94. CMOS and GaAs VLSI preampli ers were designed and tested for this occasion. The combined response of this detector and an accordion electromagnetic calorimeter prototype to muons, electrons and photons is presented. For minimum ionizing tracks a signal-to-noise ratio of 4.5 per preshower layer was measured. Above 150 GeV the space resolution for electrons is better than 250 m in both directions. The precision on the electromagnetic shower direction, determined together with the calorimeter, is better than 4 mrad above 50 GeV. It is concluded that the preshower detector would adequately ful l its role for future operation at CERN Large Hadron Collider.

Progress report on the ATLAS liquid argon presampler

“…The modules were produced by moulding a layer of micro glass ber-loaded epoxy on the top of the electrodes [5]. The electrodes were spaced and stacked by means of accurate shims in a hermetic mould.…”

“…For energies larger than 100 GeV the space resolution is better than 700 m. This space resolution strongly depends on the number of radiation lengths in front of the presampler. It is better where the amount of dead material is larger [5]. …”

“…A larger prototype of this preshower detector using 2 active l a y ers, (each of them being preceded by a lead absorber plate) was built and successfully tested at CERN [5]. The presampler will have only one active l a y er without any extra absorber material in front [6].…”