“Detector activities” after the IB upgrade
Michele Punturo
What we must do• 0 priority:
– commissioning• 1 priority:
– Items to be implemented• Acoustic shielding in the laser lab• Improvement of the cleanliness procedure in the towers• New coil drivers• … (MC LC windows?) …
– Items to be investigated:• MC end mirror
– Better substrate– Heavier payload
• BS mirror– Larger mirror
» Reduce scattered light• Eddy current dissipation• New electronics• Thermal compensation & Phase camera• New quadrant centering devices (galvanometers)• …
Virgo+ Activities
• New high power laser– N. Mann
• FS monolithic suspension activities– M.Punturo
Acoustic Shielding in the LL• Reduce the cross talk between the acoustic channel and
the dark fringe• All the racks with fans displaced during the shutdown• A coverage of the laser table and of the external injection
bench is under design– Two offers received:
• 30 k€• 16 k€
– A third company contacted• Offer in few days
– Implementation:• End of winter, beginning of spring• As soon as an executive design will be available it will be shown in a
detector meeting
Cleanliness improvement in the tower• Wednesday, past week:
• When the NI problem occurred I prepared (16/04/2003) this list of rules:– Keep the mirror clean – Remove the dust particles through an ionized air jet after the integration
and tuning procedures– Inject, during the venting only dray air– Warm up the mirror, to reduce the probability of condensation on it
• Some of them haven’t been respected– Need to patch the problem now (cleaning intervention)– Need to solve the problem in the future
• Control of the moisture• Ionized warm air flux (need of infrastructure upgrade, already indicated in
the urgent purchases in the October 2005 Detector Meeting in Naples)
Actuation Noise
G.L
osur
do
New coil drivers
LCoil3mH
1
2
RCoil10
Ref. Mass Coil
+
-
OUT
R2
R
R1R
Coil Driver
DAC 2RN
500
DAC 1Transconductance Amplifier• Full production of new coil drivers
in one year– Prototypes already installed in
the end towers (EM contamination)
– Simplified solution in the input towers (switch+resistor)
– Simplified solution in the BS tower
• New coil drivers have been designed by INFN Pisa + EGO support to solve the actuation noise problem– Two different sections
• High power section for lock acquisition• Low noise section for linear regime
– The two sections are driven by two independent DACs
NEW end MC mirror• The losses in the MC are 846 ppm (F.Bondu)
instead of 115 ppm• Defects and contamination in the curved MC mirror• This mirror must be replaced
Small or large MC mirror?
• Two new small substrates have been sent to GS Lumonics (Raffaele, could you confirm?)
• The possibility to use a large substrate must be investigated– Better control of the payload– “almost” standard geometry– Herasil substrate available– Movement mechanics complicated– Optics + Mechanics studies must be started now
New BS?• Stray light is evident in the BS
IB
WA NI
wedge
• With the higher injected power the problem should be enhanced– Larger BS needed
• New substrate (wedge) to be realized
Eddy current FUTURE problem• Virgo design
– M=0.017 A m2
– Stainless Steel RM• RM=1.4×106W-1m-1
– Qeddy=1.8×108
• Current design– M=0.05 A m2
– Aluminum RM• RM=3.2×107W-1m-1
– Qeddy=9.4×105
Experimental test: (VIR-NOT-PER-1390-27 (1996), VIR-NOT-PER-1390-80 (1997), Rev.Sci.Instr. 69, 2777 (1998))
1 1 0 1 0 0 1 0 0 01 0 - 2 3
1 0 - 2 2
1 0 - 2 1
1 0 - 2 0
1 0 - 1 9
1 0 - 1 8
h(f
) [
1/s
qrt
(Hz
)]
F r e q u e n c y [ H z ]
( a ) N o m i n a l V i r g o ( b ) C u r r e n t m a g n e t s M = 0 . 0 5 , A l R M ( c ) N o m i n a l m a g n e t s M = 0 . 0 1 7 , A l R M ( d ) M a g n e t s M = 0 . 0 0 5 , A l R M
Magnetic Field Now
mirror
postmagnet
coilMac
or s
uppo
rt
stee
l sup
port
Alu
min
um R
M
With Iron Hat
Test in Clean Room
0 1 2 30.2
0.4
0.6
0.8
1.0
B/B 0
layers of 0.6mm
Bmeas Model Model (top larger)
Conclusions
• In parallel to the commissioning activities many “detector activities” are foreseen (and many more are needed)
• Man power is an issue:– Many persons are involved in both
commissioning and “detector”