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STATUS OF EXPLORER AND NAUTILUS

STATUS OF EXPLORER AND NAUTILUS. Massimo Visco f or ROG Collaboration. INFN – LN Frascati, LN Gran Sasso, Sez . Roma 1, Roma 2 and Genova Universities “La Sapienza” and “Tor Vergata” Rome, L’Aquila, Geneve CNR – I FSI and IFN Roma CERN - Geneve.

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STATUS OF EXPLORER AND NAUTILUS

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  1. STATUS OF EXPLORER AND NAUTILUS Massimo Visco for ROG Collaboration INFN – LN Frascati, LN Gran Sasso, Sez. Roma 1, Roma 2 and Genova Universities“La Sapienza” and “Tor Vergata” Rome, L’Aquila, Geneve CNR – IFSI and IFN Roma CERN - Geneve

  2. G.W. ANTENNA EXPLORER CERN - GENEVA G.W. ANTENNA NAUTILUS LNF - FRASCATI Bar Al 5056 M = 2270 kg L = 2.97 m Ø = 0.6 m nA= 915 Hz @ T = 2.5 K Cosmic ray detector Bar Al 5056 M = 2270 kg L = 2.91 m Ø = 0.6 m nA= 935 Hz T=130 mK - dilution refrigerator Cosmic ray detector

  3. DATA TAKING DURING THE LAST 14 YEARS EXPLORER 1990 91 92 93 94 95 96 97 98 99 02 01 03 04 00 h from 10-18 to 4·10-19 NAUTILUS 96 97 98 99 02 04 01 03 00 h from 10-18 to 3·10-19

  4. EXPLORER STATUS • EXPLORER was upgraded in 1999. After a tune-up period, it has been on the air since 2000 with a duty cycle close to 85%, excluding 6 months in 2002 and 3 months at the beginning of 2004. • From March 2004 it has been working with an effective temperature around 4 mK corresponding to h = 5· 10-19. The sensitivity can be increased modifying the electrical field in the transducer. • This year we will not to interrupt the data taking during the winter closure of the CERN.

  5. NAUTILUS STATUS • It has worked in the past run from 1999 to March 2002. The duty-cycle in 2001 was about 80% and the effective temperature smaller then 5 mK corresponding to h = 6 · 10-19 • After a hardware upgrade, NAUTILUS has resumed operations in March 2003. In this phase it is working at 3.5 K with a duty cycle larger then 85 %. The effective temperature is around 1 mK corresponding to h ~ 3· 10-19 • Further improvement is possible changing the experimental parameters.

  6. EXPERIMENTAL CONFIGURATION L0 Li Small gap capacitive transducer Al 5056 mt = 0.75 kg nt= 916 Hz Ct = 11 nF E = 2.6 MV/m Superconducting matching transformer Lo=2.86 H Li=0.8mH K=0.8 High coupling dc-SQUID Ms = 10 nH fn= 3 ·10-6Fo/Hz

  7. Gap 10  m Teflon insulators Antenna • “ROSETTE” SHAPED Resonating disk Pb washers ROG GROUP TRANSDUCER 12 cm

  8. The transducer mounted on the antenna

  9. WIDENING THE BAND Old readout New readout Increasing the Bandwidth of Resonant Gravitational Antennas: The Case of ExplorerPRL 91, 11 (2003)

  10. EXPLORER and NAUTILUS December 11th, 2004 (-1/2)

  11. DATA TAKING DURING 2004 NAUTILUS EXPLORER 5 ·10-19 3·10-19

  12. NAUTILUS OPERATIONS DURING October 2004 Duty Cycle  85 % Liquid Helium Refillings

  13. EXPLORER OPERATIONS DURING October 2004 Liquid Nitrogen Refilling Liquid Helium Refillings Duty Cycle  85 %

  14. GAUSSIANITY NAUTILUS EXPLORER 12 hours of data on Sept 4th, 2004

  15. SEARCH FOR VARIOUS SOURCES • CONTINUOUS: • From the GC, 95.7 days EXPLORER hc = 3 • 10–24- frequency interval 921.32  921.38 Hz (P.Astone et al. Phys. Rev. D 65, 022001,2002 ) • From all the Sky, 2 days EXPLORER hc = 2 • 10–23- frequency interval 921.00  921.76 Hz (P.Astone et al., proceedings GWDAW 2002 – ROG – A. Krolak and collab.) • New analysis in progress • STOCHASTIC SOURCES: • Crosscorrelation of EXPLORER and NAUTILUS data over 10 hours in a band of 0.1Hz in 1997 - GW(920.2 Hz) < 60. (P.Astone, et al., Astron. and Astrophys, 351, 811-814, (1999).) • The common bandwidth now can reach 10 Hz: a new upper limit 1 is possible

  16. BURST SIGNALS: • GW detectors • Together with the other detectors of IGEC collaboration: no GW bursts above h  2 10-18 corresponding to 0.01M⊙ in the GC (International Gravitationl Event Collaboration, Phys. Rev. D 68, 022001 (2003)). • P.Astone et al.: “Study of coincidence between resonant gravitational wave detectors”, Classical and Quantum Gravity, 18, 243-251, (2001). • P.Astone et al.: “Study of the coincidences between the gravitational wave detectors EXPLORER and NAUTILUS in 2001”, Classical and Quantum Gravity 19, 5449-5463 (2002). • The analysis of the data taken by the two experiments during 2003 and 2004 is in progress.The data are available for coincidenceanalysis with the other experiments. • GW -  ray detectors • Analysis over 47 GRB (BeppoSAX) (95% probability):no signals with h>6.5·10-19for a time delay within 5 s, and with h>1.2·10-18 for a time delay within  400 s.(P. Astone et al,Physical Review D, 66, 2002 102002). • Analysis of 387 GRB (BeppoSAX and BATSE) upper bound of h=2.5·10-19in a time window of 10s (astro-ph/0408544) • GW – cosmic ray detectors • Search for small signals (P.Astone et al.,Physical Review Letter, 84, (2000)14-17) • Detection of unexpected large signals (P.Astone et al, Phys. Letters B 499, Feb 2001 16-22) (P.Astone et al, Physics Letters B 540 179-184 (2002)).

  17. Correlation between cosmic rays and signals in the antennas 100 10 1 0.1 0.01 0.001 0.001 0.01 0.1 1 10 Expected Explorer 2002 >600 P m2 Explorer 2003 Nautilus 1998 Nautilus 2000-2001 Nautilus 2000 T<1 K Nautilus 2003 Ev/day integral distribution Events amplitude - Sqrt(K)

  18. TIME RESOLUTION AND EVENTS FROM COSMIC RAYS - EXPLORER 2003 Selection of small events 4 <SNR (amplitude) <6  =5.7 ms

  19. MINIGRAIL – NEW RUN November 2004 New cryogenic run with 3 capacitive transducers and SQUID read-out. Ø 68 cm - 1.4 ton 3kHz T=72mK

  20. MINIGRAIL Strain sensitivity (Hz)-1/2

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