DAMA

Collaboration:

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

Location of the experiment: 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 investigation; 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 search; v) neutral SIMPs and neutral nuclearites search; vi) bb decay processes in different isotopes.

More on the experiments...

2.

Activities during 2002

The main goals achieved in the given period are:

~100 kg NaI(Tl) set-up

- Completion of the data taking of the 7th annual cycle
- further model dependent analyses on the annual modulation data already released, e.g. considering different possible halo models
- preliminary search for Q-balls with the ~100 kg NaI(Tl) set-up
- analyses of the data collected during the 5th, 6th and - after completion - 7th annual cycles
- dismounting completed in fall 2002

The LIBRA (Large sodium Iodide Bulk for RAre processes; ~250 kg of highly radiopure NaI(Tl)) set-up

- Installation started in fall 2002 and almost completed in 2002

~6.5 kg LXe set-up

- Preliminary results on bb decay modes in 134Xe (statistics of 0.87 kg.y)
- Results on the search for double b decay in 134Xe and 136Xe (statistics of 1.1 kg.y for the 134Xe and of 4.5 kg.y for the 136Xe).
- Further data taking.

R&D set-up

- Results on the search for b and bb decay in 48Ca
- Analysis of the data collected with CeF3 scintillator
- Preliminary data taking with BaF2

miscellaneous

- Further studies on anisotropic scintillators for Dark Matter direct measurements

The following achievements have been obtained:

- Completion for data taking with the ~100 kg NaI(Tl) set-up. (100%)
- Analysis of the data acquired.(100%)
- Dismounting of the ~100 kg NaI(Tl) set-up and installing the new LIBRA set-up. (100%)
- Data taking with enriched Xenon and analysis. (100%)
- Data taking for the R&D installation with 106Cd and analysis (100%)

Milestones 2003

Tests and runs with the LIBRA set-up | 31-12-2003
Analysis of the previously collected data | 31-12-2003
Data taking with Xenon enriched either in 129Xe or in 136Xe and related data analyses | 31-12-2003
Data taking with the R&D set-up using various scintillators | 31-12-2003

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

- Manpower: 11 researchers (9 FTE), 3 Technicians (2.1 FTE)
- Budget for the Year 2003: 1.7 % of the CSNII budget

4. Number of publications in refereed journals (in 2002): 7

5. Number of talks to conferences (in 2002): 13

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

3 doctoral thesis in progress

7. Leadership roles and primary responsibilities of the experiment

- R. Bemabei - principal investigator

8. Innovative instruments

Development of radiopure detectors, PMTs and overall set-ups.

9. Competing experiments

• 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. This set-up has concluded the data taking in 2002.

• The new ~250 kg NaI(Tl) LIBRA set-up (whose installation has been largely performed since fall 2002) has even an increased competitiveness with respect to the previous 100 kg NaI(Tl) set-up discussed above.

• 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; future possibilities will be considered.

• The features of the “R&D” set-up assures the possibility of competitive small scale experiments; some of them are in progress.

• 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.