DAMA

Collaboration:

- Italy: INFN—sez. Roma2 and University of Rome “Tor Vergata” , INFN—sez. Roma and University of Rome “La Sapienza"
- China: IHEP, Beijing

Laboratory: Gran Sasso National Laboratory (LNGS)

National Responsible: R. Bernabei (Roma2)

1. Goal of the experiment

The DAMA experiment is an observatory for rare processes such as: i) Dark Matter particles; ii) charge non-conserving (CNC) processes as electron decays in different channels, CNC electron capture in different isotopes; iii) nucleon and di-nucleon decay into invisible channels, in different isotopes; iv) solar axions; v) SIMP and neutral nuclearites; vi) bb decay processes in different isotopes.

More on the experiments...

2.

Activities during 2001 (from November 2000 to December 2000)

The Milestones of 2001:

i) Analysis of data available, both with the ~100 kg NaI(Tl) set-up and with the LXe set-up, at the time of setting the milestones 2001, on the different scientific lines.

ii) End of data taking of the new annual cycle with the ~100 NaI(Tl) set-up.

iii) Start production of new crystals and completing of electronics and PMTs for the 250 kg NaI(Tl) set-up

iv) Continuing data taking with Xe enriched in 136Xe

v) Continuing data taking with CaF2(Eu) prototype

have been fulfilled.

The main goals achieved in the given period are:

~100 kg NaI(Tl) set-up

1. New results on the investigation of possible systematics in WIMP annual modulation search.
2. Further model dependent analyses on the annual modulation data released in 2000, considering: a) WIMPs with mixed spin-independent and spin-dependent coupling; b) WIMPs with preferred inelastic scattering.
3. search for solar axions by Primakoff effect (53437 kg x day exposure).
4. completion of the data taking of the 6-th annual cycle and start of the data taking of the 7-th annual cycle.
5. data analyses in progress.

~6.5 kg LXe set-up

1. Full description of the set-up and of its performances.
2. Results on the light of a pure Liquid Xenon scintillator irradiated by 2.5 MeV neutrons.
3. Results on the search for double beta decay in 136Xe (6843.8 h running time).
4. Further data taking.

CaF2(Eu) prototypes

Data analysis on a search for beta and double beta decays of 48Ca isotope by coincidence technique.

miscellaneous

Studies on the search for neutrino oscillation by artificial neutrino source.

Milestones 2002

Data taking with the apparatus of 100 kg of NaI (Tl). | 1-08-2002
Analysis of the data acquired. | 31-12-2002
Installation of new NaI(Tl) detectors, electronics, data acquisition system; start of the data acquisition run to verify the performances of the apparatus of 250 kg of NaI (Tl). | 31-12-2002
Data taking with enriched Xenon and analysis | 31-12-2002
Data taking for the R&D installation with 106Cd and analysis | 31-12-2002

3. INFN contribution to the experiment in terms of manpower and financial support

- Manpower: 10 researchers (8 FTE), 2 Technicians (1.1 FTE)
- Budget for the Year 2002: 261 kEuro

4. Publications in refereed journals: 6

5. Number of conference talks: 9

6. Number of undergraduate and doctoral thesis on the experiment: 3

7. Leadership role in the experiment

- R. Bemabei - principal investigator

8. Innovative instruments

Development of radiopure detectors, PMTs and overall set-ups

9. Competing experimen t s

• As regards the 100 kg NaI(Tl) set-up, we recall that no other set-up with similar features (well known technique, radiopurity, exposed mass, complete monitoring and control of the running parameters, energy threshold etc.) is available to effectively search for the WIMP annual modulation signature. Moreover, it offers also the possibility to competitively exploit various other approaches (pulse shape discrimination of the electromagnetic background, search for exotic candidates etc.) and to investigate several other rare processes.

The competitiveness of our experiment will be further increased by the ~250 kg NaI(Tl) set-up (LIBRA) now under construction.

• As regards the about 2 1 (i.e. about 6.5 kg) liquid Xenon (LXe) pure scintillator set-up, we recall that no other set-up with similar features (Kr-free Xenon gas enriched in particular isotopes, radiopurity, exposed mass, complete monitoring and control of the running parameters, energy threshold, effective far UV light collection, etc.) is available. This set-up has been periodically upgraded to further increase its performances and sensitivity. Since August 2000 it can be alternatively filled with Kr-free Xenon gas enriched at 99.5 % in 129Xe or at 68.8 % in 136Xe. The advantage to use Kr-free gases as well as the enrichements in these two isotopes can be easily inferred.

• As regards the CaF2(Eu), competitive results have been achieved with previous prototypes; at present future possibilities are under consideration.

• The features of the “R&D” set-up assures the possibility of competitive small scale experiments.

• The low background Ge assures a continuum and effective work for material selection

10. International committee which has reviewed the experiment

The experiment is reviewed by the funding authorities of INFN and has also been periodically reviewed by the Scientific Committee of the LNGS. Chinese activity is funded by the National Natural Science Fund of China and Academia Sinica.