D. Mazza

Scintillation efficiency of nuclear recoil in liquid xenon

Abstract We present the results of a test done with a Liquid Xenon (LXe) detector for “Dark Matter” search, exposed to a neutron beam to produce nuclear recoil events simulating those which would be generated by WIMPs elastic scattering. The aim of the experiment was to measure directly the scintillation efficiency of nuclear recoil. The nuclear recoil considered in the test was in the tens of keV range. The ratio of measured visible energy over the true recoil energy was evaluated to be about 20%, in good agreement with the theoretical predictions.

Detection of scintillation light in coincidence with ionizing tracks in a liquid argon time projection chamber

A system to detect light from liquid argon scintillation has been implemented in a small, ICARUS-like, liquid argon time projection chamber. The system, which uses a VUV-sensitive photomultiplier to collect the light, has recorded many ionizing tracks from cosmic-rays in coincidence with scintillation signals. Our measurements demonstrate that scintillation light detection can provide an effective method for absolute time measurement of events and eventually a useful trigger signal

Performance of the 10 m 3 ICARUS liquid argon prototype

Abstract We report on the performance of a liquid Argon Time Projection Chamber, operating in a 10 m 3 cryostat. This device built in the framework of the ICARUS T600 programme to serve as a full test facility for the adopted cryogenics and mechanical solutions, was successfully tested in 2000 as the last step before the tests of the first 600 t ICARUS module 1 year later. In a final run at the Gran Sasso Laboratory, whose outcome provides the main subject of this paper, also the readout and imaging capabilities of the installed wire chamber and the overall performance of the detector have been successfully tested.

Study of solar neutrinos with the 600 t liquid argon ICARUS detector

Abstract The ICARUS time projection chamber can yield sound information on 8 B solar neutrinos. Owing to the high-energy resolution and the good capability of event reconstruction it can make a contribution to our understanding of neutrino intensities and their energy spectrum. Moreover, the MSW oscillation probability for sterile and active neutrinos can be well studied because both elastic scattering by electrons and absorption reaction on argon nuclei can be measured independently. The main problem in detecting the low-energy neutrino interactions arises from the environmental radioactivity. In the present work we study by Monte Carlo simulation the topology and the rates of the events, induced by neutrinos and background neutrons, in a 470 t (fiducial mass) liquid-argon TPC detector. For neutrino interactions we use the standard solar model BP98 and the recent experimental confirmation of the shell model computation of absorption cross section. The noise is estimated from new data on natural neutron background, collected in the hall C of the Gran Sasso laboratory. It is confirmed that, with a relatively modest neutron shielding and particular off-line event triggers, the weight of spurious events can be made to have little influence on the ICARUS solar neutrino measurement. Indeed, we expect 6 (26) background events per year in the 212 (759) elastic scattering (absorption reaction) sample.

ICARUS 600 ton: A status report

The goal of the ICARUS Project is the installation of a multi-kiloton LAr TPC in the underground Gran Sasso Laboratory. The programme foresees the realization of the detector in a modular way. The first step is the construction of a 600 ton module which is now at an advanced phase. It will be mounted and tested in Pavia in one year and then it will be moved to Gran Sasso for the final operation. The major cryogenic and purification systems and the mechanical components of the detector have been constructed and tested in a 10 m3 prototype. The results of these tests are here summarized.