Last Update: October 2000

DAMA

Collaboration:

INFN - sez. Roma2 and sez. Roma

IHEP/Beijing

physical results on particular topics achieved also in collaboration with physicists of Ukraine - INR/KieV and of ENEA-Frascati.

Laboratory: LNGS

1. Goal of the experiment

The DAMA experiment is an observatory for rare processes, mainly for Dark Matter particles. The experimental set-ups are realized by developing and using several kinds of radiopure scintillators.

The main running experimental set-ups are:
the ~100 kg highly radiopure NaI(Tl) set-up (mainly devoted to the investigation of the WIMP annual modulation signature); we note that the electronics and DAQ of this set-up have been fully upgraded in August 2000.
the ~ 6.5 l liquid Xenon (LXe) scintillator set-up (devoted to measurements with Kr-free Xenon enriched in particular isotopes);
the set-up named "R&D" that is used for measurements with prototype detectors and for small scale experiments; during 2000 the whole installation has been reassembled in a new experimental site with several hardware improvements.
the low background DAMA Ge set-up (devoted to routine measurements of samples radiopurity).

Moreover, R&D's for the further development of higher radiopure detectors and PMTs are regularly carried out.

Under construction: the NaI(Tl) set-up with ~250 kg exposed mass, which will offer further increased performances and sensitivity.

2. Physics achievement

Results published from October 1999 to October 2000.

~100 kg NaI(Tl) set-up


~6.5 kg LXe set-up

  • Second CaF2(Eu) prototype
    • New and highly improved half-life limits on the double beta decays of 40Ca and of 46Ca have been published.

     

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

    - Manpower (Year 2000): 8 researchers, 2 Technicians

    - Financial Support (Year 2000): 949 MLit

    4. Number of publication in referred journals: 8 (from October 1999 to October 2000)

    5. Number of talks to conferences: 13(from October 1999 to October 2000)

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

    7. Leadership role in the experiment

    R. Bernabei - 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.
    The competitiveness of our experiment will be further increased by the ~250 kg NaI(Tl) set-up now under construction.
  • As regards the about 2 l (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; the last one is at hand and a decision on this line of development will be taken at end of measurements.
  • The features of the "R&D" set-up assures the possibility of competitive small scale experiments.
  • 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 Commettee of the LNGS. Chinese activity is funded by the National Natural Science Fund of China and Academia Sinica.