the steering mirror control c.cerna demonstrator progress meeting 29/06/2005

the KMOS case The more stringent requirements : Temperature (30 °K) Vibration (Ariane 5 launch) Purpose of the prototype : verify the specs. @ cryo conditions : Tip-tilt range : +/- 2.5° Pointing accuracy : 1’ Pointing stability : <= 5” In terms of coding : 5°/5” = 3600 steps ~ 12bits

PC the KMOS case solution adopted in term of control : x2 axis x2 axis Coil INFINEON FP212L100 PC National Instrument NI 7342 control board 2 axis out : +/-10V, qq mA in : +/- 10V, 12bits home made ao board AD524 ampli op. U/I ampli : +/-10V, qq mA40 mA out 2 : +5V, 10 mA stable ampli op. : g=10

the demonstrator case The more stringent requirement : control the dithering test at 120 °K

the demonstrator case qX = +/- 0.258° qY = +/- 1.15° 250 mm 2.5 mm 10 mm Z stack Tip-tilt : qX = +/- 0.258° qY = +/- 1.15° steering position pointing accuracy : dithering : moving a PSF on the slices of a known value to be sure that the image of the PSF on the detector has moved of 1/10 of pixel 1/10 of IR pixel = 39 mm on the slices  qaccuracy = 33 “ Absolute accuracy : be able to measure 33” means have an absolute accuracy of about 3”  dqaccuracy ~ 3“

<12bits the demonstrator case in terms of coding : en x : 0.516°/3” ~ 9bits en y : 2.3°/3” ~ 11.4bits in terms of signal amplification : As the tip-tilt is at least twice lower than in KMOS case, AO gain have to be at least twice higher g~20-50 in terms of motor power : As mechanical part is optimised (PEB) one can imagine than 40mA will be enough to move the actuators <12bits

demonstrator solutions Coil INFINEON FP212L100 500€ 800€ <300€ @ home expensive outside NI 7342 ao board : U/I converter stable alim ao g~10-100 4ch 16bits an. input 8ch Alim 24V alim rack control 1000€ ~3000€ ? Coil INFINEON FP212L100 ao g~10-100