WARP

Collaboration

- Italy: Laboratori Nazionali di Gran Sasso, INFN; Department of Physics and INFN, University of Padova; Department of Physics and INFN, University of Milano; Department of Physics and INFN, University of Naples "Federico II"; Department of Physics and INFN, University of Pavia; Politecnico di Milano (CESNEF), University of Milano; Department of Physics and INFN, University of L'Aquila; Universita' of Torino; INFN Pisa, San Piero a Grado (PI); ICGF del CNR di Torino, Torino.
- CERN, Geneva, Switzerland.
- People's Republic of China: IHEP - Academia Sinica, Beijing.
- Switzerland: Institute for Particle Physics, ETH Honggerberg, Zurich,
- USA: Department of Physics, UCLA, Los Angeles,

Laboratory: Gran Sasso National Laboratory
1. Goal of the experiment
The experiment aims at the unambiguous identification of Dark Matter candidates (WIMPS) by means of the detection of nuclear recoils in liquid argon. The proposed technique combines the experience and the tools developed for the ICARUS experiment for handling ultra-purified liquid argon and for detecting the argon scintillation light with the technique developed, also by the ICARUS Collaboration, for detecting and discriminating nuclear recoils in liquid xenon.
2.

Activities during 2002
During 2002 the small prototype of the two-phase chamber was reconfigured, by adding a waveshifing/reflector layer (to increase the light collection efficiency and to minimize dead zones potentially source of fake signals) and by reducing the active volume. Several calibration and test runs were made using both X-rays, g and neutron sources. Very good light collection efficiency was obtained (superior to the best value reached with xenon chambers) with correspondingly good energy resolution. Highly efficient discrimination between X-rays and nuclear recoil events (from neutrons interactions) was demonstrated down to very low recoil energy thresholds (30 keV or less).

Milestones 2003

This development activity is currently under examination by the CSN2

(If approved by the CSN2 and by the LNGS authorities, the activity will proceed with the run of the small prototype in LNGS mainly for neutron background measurements. A larger prototype will also be built also dedicated to background studies both from the environment and from construction materials).

3. INFN contribution to the experiment in terms of manpower and financial support
The activity is currently carried on as part of the R&D for the ICARUS experiment on scintillation light detection both in the INFN Pavia laboratory and in CERN. Financial support is completely given by INFN through INFN funding of the general activities of the Pavia Gruppo II (expense chapter Dotazioni) and as part of the contribution to the ICARUS activity. People actively working on the subject are from the INFN Pavia group and from the Italian components of the Icarus Collaboration (from Padova and Torino) working at CERN. The involved researchers are 11 (3.6 FTE) with the technical support from the partecipating Sezioni.
4. Publications in refereed journals: 0
5. Conferences talks: 0
6. Number of undergraduate and doctoral thesis on the experiment: 0
7. Leadership role in the experiment
C. Rubbia (Universita' degli Studi di Pavia ed INFN Sezione di Pavia) Spokesman
8. Innovative instruments
9. Competing experiments
The project is in competition with the many experiments working on Dark Matter (DAMA, CUORE, etc.)