LVD

Collaboration

- Italy: University of Bologna and INFN; INFN-LNF, Frascati; INFN-LNGS, Assergi; Institute of Cosmo-Geophysics, CNR, Torino, University of Torino and INFN-Torino
- Brazil: University of Campinas, Campinas
- Japan: Okayama University, Okayama; Okayama University of Science, Okayama; Hirosaki University, Hirosaki; Ashikaga Institute of Technology, Ashikaga
- Russia: Institute for Nuclear Research, Russian Academy of Sciences, Moscow
- USA: Brown University, Providence; University of Houston, Houston; Indiana University, Bloomington; Massachusetts Institute of Technology, Cambridge

Laboratory: LNGS-Gran Sasso National Laboratory

National Responsible: A. Zichichi

1. Goal of the experiment.

The LVD experiment was conceived with a twofold purpose: the study of high energy cosmic ray processes deep undergound and the study of low energy neutrino bursts, typically originated in the Super Nova gravitational stellar collapses.

More on the experiment...

2.

Activities during the year 2001

The LVD experiment, in the final configuration of 3 towers (~1 kton of active mass), has taken data with an average duty cycle of more than 99% monitoring the Galaxy for Super Nova stellar collapses. No such event has been observed.

Tests have been made either on the recognition of neutrino bursts by using clusters simulated by LED's or on the operation in high-rate coincidence mode with the SuperKamiokande and SNO detectors in the framework of the SNEWS project, dedidated to the simultaneous detection of the Supernova events.

The apparatus has been upgraded with an active radiation shielding based on 72 counters belonging to the LSD detector, operated at Mont Blanc and now dismissed.

The following milestones were set by the Italian groups for 2001:

- Completion of conditioning of the third tower and Data Acquisition for the three towers: fulfilled on 31-01-2001

- Completion of tests with doped liquid scintillator: 80% fulfilled

- Gammas and neutrons passive filter installation: fulfilled on 31-07-2001

Milestones 2002

Data taking with the whole detector at the maximum efficiency | 31-12-2002
Completion of SNEWS synchronization test | 31-12-2002
Completion of studies to improve the detector performance | 31-07-2002

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

- Manpower: 24 researchers (10.7 FTE), 3 technicians (1.3 FTE)

- Budget for the Year 2002: 284 kEuro

4. Publications in refereed journals (in 2001):

5. Conference talks (in 2001): 4

6. Number of undergraduate and doctoral theses on the experiment

Laurea diplomas: 2

7. Leadership roles and primary responsibilities in the experiment

Spokeperson and Chairman of the Executive Committee (A. Zichichi), Chairman of the Analysis Committee (P. Galeotti), Chairman of the Technical Committee (P. Giusti).

8. Innovative instruments

The LVD collaboration has set up in the Gran Sasso Laboratory a plant for the production of the good quality and inexpensive liquid scintillator needed for the experiment. Nowadays it is used to develop new liquid scintillators with improved characteristics by using various dopants.

9. Competing experiments

Relative to the detection of low energy neutrino bursts, the main competing experiments are SuperKamiokande, SNO, AMANDA. LVD compares well with respect to these experiment due to its following characteristics.

- LVD can operate with a lower neutrino energy threshold than the experiments based on Cerenkov light detection (SuperKamiokande, SNO, AMANDA). This is an important characteristics to be able to study objects emitting at low temperature n-sphere. Moreover, the lower energy threshold should allow for the observation of the low energy neutrino burst emitted, according to some models, when a star collapses into a black hole.

- LVD can identify with high efficiency the dominant reaction (anti-n e p --> e+ n) detecting the delayed g emitted in the neutron capture, and not simply by the lack of directionality as for light water Cerenkov detectors. Therefore LVD can measure a clean anti-n e energy spectrum and separate the rare but very interesting charged and neutral current interactions with Carbon nuclei .

- The modularity of the LVD apparatus allows for good calibration and maintenance of the detector without loosing live time at the expense of a small reduction of the active detector mass. In the last years LVD has been watching for stellar collapses in the Galaxy with an average duty cycle greater than 99%.

10. International Committee which has reviewed the experiment.

The LVD experiment has been reviewed and approved by the LNGS International Scientific Committee.