“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

qr

t(H

z)

]

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

coilMa

cor

sup

po

rt

ste

el s

up

po

rt

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”