1. GWDAW 9 - December 15 th, 2004 STATUS OF EXPLORER AND NAUTILUS 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 Massimo Visco for ROG Collaboration

2. GWDAW 9 - December 15 th, 2004 G.W. ANTENNA NAUTILUS LNF - FRASCATI G.W. ANTENNA EXPLORER CERN - GENEVA Bar Al 5056 M = 2270 kg L = 2.97 m Ø = 0.6 m A = 915 Hz @ T = 2.5 K Cosmic ray detector Bar Al 5056 M = 2270 kg L = 2.91 m Ø = 0.6 m A = 935 Hz T=130 mK - dilution refrigerator Cosmic ray detector

3. GWDAW 9 - December 15 th, 2004

4. DATA TAKING DURING THE LAST 14 YEARS 1990919293949596979899 00 01 02 EXPLORER NAUTILUS 03 96979899 00 01 02 03 h from 10 -18 to 4·10 -19 h from 10 -18 to 3·10 -19 0404 0404

5. GWDAW 9 - December 15 th, 2004 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. EXPLORER STATUS

6. GWDAW 9 - December 15 th, 2004 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. NAUTILUS STATUS

7. GWDAW 9 - December 15 th, 2004 EXPERIMENTAL CONFIGURATION Small gap capacitive transducer Al 5056 m t = 0.75 kg t = 916 Hz C t = 11 nF E = 2.6 MV/m Superconducting matching transformer Lo=2.86 H Li=0.8  H K=0.8 High coupling dc-SQUID M s = 10 nH  n = 3 ·10 -6  o/  Hz L0L0 LiLi

8. GWDAW 9 - December 15 th, 2004 ROG GROUP TRANSDUCER Antenna Resonating disk Teflon insulators Pb washers Gap 10  m “ROSETTE” SHAPED 12 cm

9. GWDAW 9 - December 15 th, 2004 The transducer mounted on the antenna

10. GWDAW 9 - December 15 th, 2004 Old readout New readout WIDENING THE BAND Increasing the Bandwidth of Resonant Gravitational Antennas: The Case of Explorer PRL 91, 11 (2003)

11. GWDAW 9 - December 15 th, 2004 EXPLORER and NAUTILUS December 11th, 2004 (-1/2)

12. GWDAW 9 - December 15 th, 2004 DATA TAKING DURING 2004 EXPLORER NAUTILUS 5 ·10 -19 3·10 -19

13. GWDAW 9 - December 15 th, 2004 NAUTILUS OPERATIONS DURING October 2004 Liquid Helium Refillings Duty Cycle  85 %

14. GWDAW 9 - December 15 th, 2004 EXPLORER OPERATIONS DURING October 2004 Liquid Helium Refillings Duty Cycle  85 % Liquid Nitrogen Refilling

15. GWDAW 9 - December 15 th, 2004GAUSSIANITY EXPLORER NAUTILUS 12 hours of data on Sept 4 th, 2004

16. GWDAW 9 - December 15 th, 2004 SEARCH FOR VARIOUS SOURCES CONTINUOUS: – From the GC, 95.7 days EXPLORER h c = 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 h c = 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

17. GWDAW 9 - December 15 th, 2004 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 coincidence analysis with the other experiments. GW -  ray detectors Analysis over 47 GRB (BeppoSAX) (95% probability):no signals with h>6.5·10 -19 for 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 -19 in 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)).

18. GWDAW 9 - December 15 th, 2004 0.001 0.01 0.1 1 10 100 0.0010.01 0.1110 Explorer 2003 Expected Explorer 2002 >600 P m 2 Nautilus 2003 Nautilus 2000-2001 Nautilus 1998 Nautilus 2000 T<1 K Ev/day integral distribution Events amplitude - Sqrt(K) Correlation between cosmic rays and signals in the antennas

19. GWDAW 9 - December 15 th, 2004 TIME RESOLUTION AND EVENTS FROM COSMIC RAYS - EXPLORER 2003 Selection of small events 4 <SNR (amplitude) <6  =5.7 ms

20. GWDAW 9 - December 15 th, 2004 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

21. GWDAW 9 - December 15 th, 2004 MINIGRAIL Strain sensitivity (Hz) -1/2