Alignment Hardware Software Status Henrich Heitmann Julien Marque

Alignment : Hardware & Software Status Henrich Heitmann, Julien Marque with the contribution of: INFN Frascati, Mario Favati, Dominique Le Galliot, Alain Masserot, Flavio Nocera, Tatania Zelenova 25/01/2006 European Gravitational Observatory 1

Contents 1. Hardware review 2. Software review 3. Last upgrades 4. a. Rearrangement of crate C 34 b. The 9 th quadrant c. Global Control news d. The offset issue 25/01/2006 European Gravitational Observatory 2

1 a. The quadrant (Frascati) • Silicon photodiode, type EG&G YAG 444 • sensitivity = 0. 45 A/W • DC power = 2. 77 m. Wmax • transimpedance = 2 k • Bias voltage = 180 V 25/01/2006 European Gravitational Observatory 3

25/01/2006 European Gravitational Observatory Phase shifter board Demodulation board 1 b. Quadrant electronics (Frascati) 4

1 c. The translation stages (Frascati) 2 translation stages / quadrant (PI/M-125. 90) 1 translation stage control module : 4 translation stages control boards + quadrant power supply 25/01/2006 European Gravitational Observatory 5

1 d. Flippers, Shutters (Frascati) Shutter used to measure DC offsets. - shutter control card by Frascati. Mirrors (or neutral densities) mounted on flip-mount to attenuate the light when diode used in 2 different configurations recombined/recycled (ratio of 1000 in DC power). - will install next week proper power supply. - need for their own electronics? 25/01/2006 European Gravitational Observatory 6

2 a. The photodiode readout, translation stage control (LAPP/Napoli) Phase tuning, Gain control… Quadrant motion control… 25/01/2006 European Gravitational Observatory 7

2 b. The Global Control (LAL) Compute correction signals to be sent to the DSP of each mirror to be applied to the reference mass 25/01/2006 European Gravitational Observatory 8

2 c. The automation (LAPP/Napoli) Alignment automation consits of: prealignment of the direct beam, prealignment of the north and west arm cavities, closing linear alignment loops on all mirror. 25/01/2006 European Gravitational Observatory 9

2 d. The alignment UI (EGO) Used for the commissioning of the linear alignment (need to migrate to Labview? ) + automatic measurement and reconstruction of the optical matrix (Maddalena, Gabriele) 25/01/2006 European Gravitational Observatory 10

3 a. Rearrangement of the electronics Operation needed to: -separate analogic fron digital electronics -accommodate the electronics for the 9 th quadrant +Hardware monitoring completed +New electronics for DC remote control gain 25/01/2006 European Gravitational Observatory 11

3 b. The 9 th Quadrant Everything installed but the cables (+ problem of communication between a 3 rd translation stage driver and the rio to be fixed) No more spare!!!!! Need for a 10 th quadrant next year? 25/01/2006 European Gravitational Observatory 12

3 c. Global Control news New features for the alignment part of GC: -All matrices on the fly, -Integrated filters in GC (output and input), -Possibility to inject coherent lines on all mirrors for matrix measurement comodity, Need to write some code still… 25/01/2006 European Gravitational Observatory 13

3 d. The offset issue Where the offsets of AC error signals are coming from? a)DC offsets between different elements of the quadrant => beam not centered on diode => coupling with longitudinal signals => offset on alignment AC signals This should have been fixed by a better DC tuning b)Multireflection in the splitters of the optical setup => secondary beam combined with main beam => offset on alignment AC signal Optics with 3 degrees wedge have been acquired: will be installed soon 25/01/2006 European Gravitational Observatory 14