ILIAS WG1 - April 7 th, 2005 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 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

ILIAS WG1 - April 7 th, 2005 DATA TAKING DURING THE LAST 15 YEARS EXPLORER NAUTILUS h from to 4· h from to 3·

ILIAS WG1 - April 7 th, 2005 From March 2004 it has been working with an effective temperature around 4 mK corresponding to h = 5 · The sensitivity could be increased modifying the electrical field in the transducer. This year the data taking was not interrupted during the winter closure of the CERN. EXPLORER STATUS

ILIAS WG1 - April 7 th, 2005 After a hardware upgrade, NAUTILUS has resumed operations in March 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 · Further improvement is possible changing the experimental parameters. NAUTILUS STATUS

ILIAS WG1 - April 7 th, 2005 DATA TAKING DURING EXPLORER NAUTILUS 5 · ·10 -19

ILIAS WG1 - April 7 th, 2005 Since May 2004 operations in coincidence between ALLEGRO EXPLORER NAUTILUS Starting from December 2004 to February 2005 ALLEGRO AURIGA NAUTILUS EXPLORER operated together Now AURIGA NAUTILUS and EXPLORER are operating together NEW IGEC OPERATION We hope to have soon VIRGO AURIGA EXPLORER and NAUTILUS operating together to exchange data

ILIAS WG1 - April 7 th, 2005 NAUTILUS OPERATIONS DURING October 2004 Liquid Helium Refillings Duty Cycle  85 %

ILIAS WG1 - April 7 th, 2005 NAUTILUS OPERATIONS DURING march 2004 Liquid Helium Refillings

ILIAS WG1 - April 7 th, 2005 EXPLORER OPERATIONS DURING October 2004 Liquid Helium Refillings Duty Cycle  85 % Liquid Nitrogen Refilling

ILIAS WG1 - April 7 th, 2005 EXPLORER OPERATIONS DURING march 2004 Liquid Helium Refillings Liquid Nitrogen Refilling Field increased

ILIAS WG1 - April 7 th, 2005 EXPLORER - 5 April h starting 1am 1h starting 11am night day

ILIAS WG1 - April 7 th, 2005 NAUTILUS - 5 April h starting 1am 1h starting 11am night day

ILIAS WG1 - April 7 th, 2005 EXPLORER and NAUTILUS December 11th, 2004 (-1/2)

ILIAS WG1 - April 7 th, 2005 EXPLORER and NAUTILUS April 5th, 2005

ILIAS WG1 - April 7 th, 2005 EXPLORER- increasing the field – march 2005

ILIAS WG1 - April 7 th, 2005 EXPLORER march 2005 Fit with a model

ILIAS WG1 - April 7 th, 2005 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

ILIAS WG1 - April 7 th, 2005 CtCt CdCd R L1L1 L2L2 L in Brownian force acting on the Antenna 4K b T  a  M a /Qa GW Brownian force acting on the Transducer 4K b T  t  M t /Q t Brownian noise electrical circuit 4K b T  el  L/Q el Noise SQUID  n Coupled by electrical field

ILIAS WG1 - April 7 th, x10 6 V/m 6 x10 6 V/m 1 x10 7 V/m EXPLORER Increasing the field

ILIAS WG1 - April 7 th, 2005 EXPLORER – different components of noise - 2 x 10 6 V/m

ILIAS WG1 - April 7 th, 2005 EXPLORER – different components of noise - 6 x 10 6 V/m

ILIAS WG1 - April 7 th, 2005 EXPLORER – different components of noise V/m

ILIAS WG1 - April 7 th, 2005 MINIGRAIL Strain sensitivity (Hz) -1/2

ILIAS WG1 - April 7 th, 2005