LVD

Collaboration

- Italy: University of Bologna and INFN; INFN-LNF, Frascati; INFN-LNGS, Assergi; University of Torino and INFN; IFSI-CNR of Torino.
- Brasil: University of Campinas, Campinas.
- Japan: Okayama University, Okayama; Kawasaki Medical School, Kurashiki; 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 underground and the study of low energy neutrino bursts, typically originated in the Super Nova gravitational stellar collapses.

More on the experiment...

2.

Activities during 2002

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 99.5% monitoring the Galaxy for Super Nova stellar collapses. No such event has been observed.

In the framework of the SNEWS network, dedicated to the simultaneous detection of the Supernova events, we analyzed the data collected during the tests with SuperKamiokande and SNO and we investigated on the proper way to have a computer server with a very high security level. That is a very strict requirement from our SNEWS partners in order to start automatic alert.

The study on doped liquid scintillator continued. We put one tank in the tunnel in order to study the effects of the natural radioactivity.

The following achievements have been obtained:

- Data taking with the whole detector at the maximum efficiency (100 %)
- Completion of SNEWS synchronization test (100 %) (*)
- Completion of studies to improve the detector performance (60 %) (**)

(*) The automatic SuperNova alert will start as soon as the security of the LNGS server will be certified.

(**) We couldn’t complete the work due to lack of funding

Milestones 2003

Data taking at the highest efficiency and uptime | 31-12-2003
Upgrade of the clock distribution system and synchronization to TDCs. | 31-12-2003
Continuation of collaboration in the SNEWS system. | 31-12-2003

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

- Manpower: 25 researchers (12.5 FTE), 3 technicians (2 FTE)

- Budget for the Year 2003: 1.6 % of the CSN2 budget for 2003

4. Publications in refereed journals (in 2002): 1

5. Conference talks (in 2002): 2

6. Number of undergraduate and doctoral theses on the experiment

Laurea diplomas: 1

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 and, until the end of 2000, MACRO. 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.