6th Edoardo Amaldi Conference on Gravitational Waves Okinawa, June 20-24, 2005 Approaching the quantum limit with a new read-out on EXPLORER and NAUTILUS Alessio Rocchi University of Rome “Tor Vergata” and INFN Roma 2 for the ROG Collaboration www.lnf.infn.it/esperimenti/rog [email protected]
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6th Edoardo Amaldi Conference on Gravitational Waves ... file21st June 2005 Amaldi 6 - Alessio Rocchi EXPLORER and NAUTILUS Duty cycle more than 90% NAU = 2 mK h =
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6th Edoardo Amaldi Conference on Gravitational WavesOkinawa, June 20-24, 2005
Approaching the quantum limit with a new read-out on EXPLORER and NAUTILUS
Alessio RocchiUniversity of Rome “Tor Vergata” and INFN Roma 2for the ROG Collaboration
1 see Vinante et al., Physica C 368, 176-180 (2002)
21st June 2005 Amaldi 6 - Alessio Rocchi
Energy resolution vs temperature
0
50
100
150
200
0 1 2 3 4 5
N
T (K)
@ T=2.0 K, the flux noise is 0.21µΦ0/√Hz corresponding to 70ħ
21st June 2005 Amaldi 6 - Alessio Rocchi
Next Steps
• Investigate temperatures below 2 K;• Increase the transformer coupling;• Measurement of back-action to estimate noise temperature Tn;• Couple the system to the double gap transducer.
21st June 2005 Amaldi 6 - Alessio Rocchi
10-22
10-21
10-20
850 900 950 1000
Stra
in s
ensi
tivity
(Hz-1
/2)
Frequency (Hz)
3·10-22
Expected Sh for NAUTILUS @ 0.12K, double gap transducer (11 µm and Q=1.5·106) and double SQUID (L0=2.5 H, k=0.7, Φn= 0.16µΦ0/√Hz).
Teff ≈ 7µK (corresponding to h=2.1·10-20), sensitivity < 1·10-21 /√Hz over 35Hz.
21st June 2005 Amaldi 6 - Alessio Rocchi
21st June 2005 Amaldi 6 - Alessio Rocchi
0
100
200
300
400
500
600
0 1 2 3 4 5
N ROGN MiniGrailN AURIGA
N
T (K)
21st June 2005 Amaldi 6 - Alessio Rocchi
10-2 10-1 100 101 102 103 10410-8
10-7
10-6
10-5
Experimental flux noise spectral density of the Rome double stage SQUID amplifier