ROG
Collaboration:
Laboratory: CERN and LNF
National Responsible: E. Coccia (Roma2)
1. Goal of the experiment
ROG (the acronym stands for Ricerca Onde Gravitazionali Gravitational Wave Research) is a collaboration which has designed and constructed two massive (M=2.3 tons) cryogenic resonant bar detectors: EXPLORER, cooled at 2 K, in operation at CERN since 1990, and NAUTILUS, cooled at the record temperature (for such massive bodies) of 0.1 K, in operation at LNF since 1995.
The goal is the detection and study of gravitational wave signals emitted by high frequency (kHz) cosmic sources, such as gravitational collapses with formation of neutron stars and black holes, coalescing binaries, fast pulsars and a stochastic background.
2.
Activities during 2001
The EXPLORER detector has taken data continuously with 80% duty cycle and high sensitivity. The typical value of the noise temperature has been between 2 and 3 mK. The strain sensitivity has been of about 2x10-21 Hz-1/2 with a bandwidth of about 10 Hz.
The bandwidth is of about 40 Hz at a strain level of 10-20 Hz-1/2 . This result demonstrates that the bandwidth of resonant detectors can be increased.
NAUTILUS has operated continuously during all the year, with a duty cycle near 80%.
The detector is equipped with a cosmic ray telescope, and was capable to detect signals due to the interaction of EAS on the bar. In order to investigate the unexpected energetic signals detected last year, during 2001 NAUTILUS was operated at a thermodynamic temperature of1.5 K, above the superconducting transition temperature of the bar material.
We remind the reader that the detection of cosmic rays with NAUTILUS means being able to measure impulsive signals exciting the mode of vibration to an energy of 10-7 eV.
A new readout system including a new resonant transducer, has been prepared for the next NAUTILUS run, when the detector will be tuned at 935 Hz frequency to search for the possible gravitational wave signal coming from the pulsar remnant of SN1987a.
All the planned milestones have been fulfilled:
Continuos data taking with Explorer at Teff<10 mK
Continuos data taking with Nautilus at Teff<5 mK
Milestones 2002
EXPLORER: continuos data taking with Teff<5 mK and cosmic ray detector | 30-06-2002 |
NAUTILUS: continuos data taking with Teff<1 mK and detector tuned on pulsar of the SN1987A | 30-06-2002 |
3. INFN contribution to the experiment in terms of manpower and financial support
Manpower: 26 physiscists (16.6 FTE). 11 technicians (6.5 FTE).
Budget for the Year 2002: 339 kEuro.
4. Publications in refereed journals (Year 2001): 3
5. Conference talks (Year 2001): 9
6. Number of undergraduate and doctoral thesis:
2 Laurea diplomas.
7. Leadership roles and primary responsibilities in the experiment
8. Innovative instruments
9. Competing experiment
10. International committee which has reviewed the experiment