European Gravitational Observatory25/01/20061 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
European Gravitational Observatory25/01/20062 Contents 1.Hardware review 2.Software review 3.Last upgrades a. Rearrangement of crate C34 b. The 9 th quadrant c. Global Control news d. The offset issue
European Gravitational Observatory25/01/ a. The quadrant (Frascati) Silicon photodiode, type EG&G YAG 444 sensitivity = 0.45 A/W DC power = 2.77 mW max transimpedance = 2 k Bias voltage = 180 V
European Gravitational Observatory25/01/ b. Quadrant electronics (Frascati) Demodulation board Phase shifter board
European Gravitational Observatory25/01/ c. The translation stages (Frascati) 2 translation stages / quadrant (PI/M ) 1 translation stage control module : 4 translation stages control boards + quadrant power supply
European Gravitational Observatory25/01/ 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?
European Gravitational Observatory25/01/ a. The photodiode readout, translation stage control (LAPP/Napoli) Phase tuning, Gain control… Quadrant motion control…
European Gravitational Observatory25/01/ b. The Global Control (LAL) Compute correction signals to be sent to the DSP of each mirror to be applied to the reference mass
European Gravitational Observatory25/01/ 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.
European Gravitational Observatory25/01/ 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)
European Gravitational Observatory25/01/ 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
European Gravitational Observatory25/01/ 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?
European Gravitational Observatory25/01/ 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…
European Gravitational Observatory25/01/ 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