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Status of MiniGRAIL. G. Frossati, A.de Waard, L.Gottardi and O.Usenko Kamerlingh Onnes Laboratory Leiden, The Netherlands. ESF exploratory workshop: Toward a 3 rd generation European Gravitational Wave Observatory Perugia, 21-23-Sept. 2005. Advantages of Spheres. - PowerPoint PPT Presentation
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www.minigrail.nl
Status of MiniGRAILG. Frossati, A.de Waard, L.Gottardi
and O.Usenko
Kamerlingh Onnes LaboratoryLeiden, The Netherlands
ESF exploratory workshop: Toward a 3rd generation
European Gravitational Wave Observatory
Perugia, 21-23-Sept. 2005
www.minigrail.nl
Advantagesof Spheres
• Large cross section compared with a traditional bar detector
• Omni-directional• Determine direction and
polarization (TIGA)• Short cool-down time• Relatively cheap• Toroidal modes could be used as
vetoes for non-GW signals.
www.minigrail.nlwww.minigrail.nl
MiniGRAIL
Material CuAl6%Diameter = 0.68 mMass M ~ 1400 kgResonance freq. 2850/3050 HzAimed temperature ~ 20 mKQL sensitivity h~4x10-21
QL spectral amplitude ĥ~4.5x10-23
www.minigrail.nl
Sensitivity
Minimum detectable energy Teff=T/Q +2TN
N B NE = k T =1 h with = 3KHz
For a SQUID noise energy of one quantum
-7NT 1.5×10 K Need~0.05; Q~2x106: T~30 mK
4.5QL -23h ×10 / Hz
www.minigrail.nl
MiniGRAILInitial goal Advanced Quantum limit
EN 100 h 10 h 1 h
TN 1.510-5 1.510-6 1.510-7
Teff 4.210-5 4.210-6 4.210-7
0.1 0.1 0.1
f 224 224 230
h0 310-20 9.510-21 310-21
4.510-22 1.610-22 4.510-232/10 )( HzfSh
www.minigrail.nl
MiniGRAILCryogenics
cryostat
Liquid N2 77K (-196 ºC)
Liquid He4K (-269 ºC)
Dilution refrigerator(10 mK)
www.minigrail.nl
Kamerlingh Onnes LaboratoryUltra-low temperature lab
MiniGRAILcryostat
www.minigrail.nl
MiniGRAILSeismic isolation
~ 50 dB
www.minigrail.nl
MiniGRAILCryogenics
www.minigrail.nl
Closed Membrane Capacitive Transducer
Advantages:• Compact design• Easy to make
electrode
membrane
mass (~ 200 g)spring
CuAl6%
d~30 micro mVBIAS up to 500 V
www.minigrail.nl
New one or two-modes transducer
www.minigrail.nl
Very low noise amplifier; 2-stage SQUID
second SQUIDfirst SQUID
transformer
www.minigrail.nl
MiniGRAIL sensitivity - run 6
1.5 x 10-20
www.minigrail.nl
MiniGRAIL sensitivity - run 6
Run 6T 5 K 700 ħQ 105
M 200 gC 1.1 nFVbias 200 V
Run8T 80 mK 100 ħQ 106
M 400 gC 1.5 nFVbias 300 V
Teff = 40 K4.5 x 10-22
www.minigrail.nl
MiniGRAIL sensitivity - comparison
Initial target large interferometers
GEO 05
LIGO S3
NAUTILUS / EXPLORER
AURIGA
MiniGRAIL run6
MiniGRAIL expected run 8
www.minigrail.nl
Run 8: resonance spectrum at 200V
www.minigrail.nl
www.minigrail.nlNext: 33 ton sphere ?Project together with the Roma
group to be submitted to INFN
hQL ≈4x10-24/√Hz
hQL≈4x10-23/√Hz