MUNU

Collaboration:

- Italy: INFN and Dipartimento di Fisica dell'Università Padova
- France: Institut des Sciences Nucléaires, IN2P3-UJF, Grenoble
- Switzerland: Institut de Physique, Neuchâtel; Physik-Institut, Zürich

Location of the experiment: Nuclear reactor at Nuclear Centre Bugey (Fr)

National Responsible: Carlo Broggini (Pd)

1. Goal of the experiment

MUNU was designed to study the anti(ne)-e- elastic scattering with the antineutrinos from a nuclear reactor. Its aim is to get a precise measurement of the anti(ne)-e- differential cross section down to a kinetic energy of the recoiling electron of 0.3 MeV. In this way the experiment can be sensitive to a neutrino magnetic moment in the 10-11 Bohr magneton region. As a matter of fact, a non-vanishing neutrino magnetic moment producesanti(ne)-e- scattering events in addition to the ones due to the weak interaction.

More on the experiment…

2.

Activities during 2001

The experiment is taking data. The detector itself is working as expected, giving a very good event reconstruction.

In 2001 we reached a background rate very similar to the one measured in the Gran Sasso underground laboratory by ultra-low background and much shielded germanium detectors. With such a low background we have the evidence, for the first time, of the antineutrino peak from the reactor, that is an excess of events pointing back to the reactor. We are now taking the reactor-off data: any rigorous conclusion on the cross section value has to await the results of their analysis.

The following achievements have been obtained:

- Continuation of the data taking for at least one year, after the cathode replacement (100%)

Milestones 2002

Completion of the data taking | 31-03-2002
Completion of the detector dismounting | 30-09-2002

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

Manpower: 5 researchers (2.6 FTE), 1 technician (0.7 FTE) and the support from the Padova INFN workshops. We had a German physicist working with us for 3 years with a non permanent INFN position, and we now have a French physicist with an INFN post-doc fellowship.

Budget for the year 2002: 54 kEuro

4. Publications in refereed journals (in 2001): 2

5. Number of conference talks (in 2001): 4

6. Number of undergraduate and doctoral thesis on the experiments (2001)

7. Leadership roles and primary responsibilities in the experiment:

C.Broggini (INFN Pd): Spokesman

Padova group: they had the responsibility for the design and construction of the acrylic TPC, of the system to regulate the pressure in the TPC and in the anti-Compton and of the system to store and to transfer the liquid scintillator from the anti-Compton They also developed the slow control system and the software for the event display.

8. Innovative Instruments

9. Competing experiments

A Russian group is preparing a detector to measure the neutrino magnetic moment at Krasnoyarsk reactor.

10. International committee which has reviewed the experiment

The Committee II of INFN annually reviews the experiment.