Ivan Procházka, Jan Kodet presented at : seminart ACES – ELT Meeting, Fundamental Station Wettzell, Technische Univ.Muenchen, Germany May 8, 2009 Czech Technical University in Prague, Czech Republic Actual status of SPAD detector development for ELT - ACES mission

I.Prochazka, Wettzell, May 8, 2009 Prague group activities fall 2008 May 2009 n Detector package for WLRS # 1 (delivered) # 2 (reference) n Indoor tests # 2 (jitter, dark, background..) n Development of the ELT package u Version 1.0CMOS, low powerOK u 1.1 Bias voltage / temperature compensation OK u 1.2. Temperature drift compensation in progress n Detection absolute delay determinationpromissing n Contribution to WLRS experiment n Long term stability tests / SLR Graz /OK

I.Prochazka, Wettzell, May 8, 2009 Detector package for WLRS # 1 n Delivered, operational since fall 2008 n re-checked in Prague April 8, 2009

I.Prochazka, Wettzell, May 8, 2009 Detector package for WLRS # 2 - reference n Optimised Nov.-Dec n Prague indoor tests n Wettzell comparison tests April 8, 2009

I.Prochazka, Wettzell, May 8, 2009 Detector package for WLRS # 2 - reference n Operational up to 200 Mc /s of background photon flux n Timing jitter < 25 ps rms overall using 48 ps laser pulse n Detection delay stability +/- 4ps over entire background dynamical range

I.Prochazka, Wettzell, May 8, 2009 Development of the ELT package Version 1.0CMOS, low power n CMOS version, low power < 50 mW (detector) < 500 mW (power s.) n Ver Bias voltage / temperature compensation OK detector bias controlled within the temp. range of -50… +50 C

I.Prochazka, Wettzell, May 8, 2009 Development of the ELT package Version 1.1.CMOS, low power n Detection delay dependence ~ 60 ps / V at 2.5 V ab = > +/- 3 ps delay stability using bias stabilizing circuit n Timing jitter 1.5 V above 48 ps laser pulse

I.Prochazka, Wettzell, May 8, 2009 Development of the ELT package Version 1.2.CMOS, temperature drift compensation n The new detector electronics is automatically compensating the temperature variations of the detector electronic circuit delay including the delay temperature drift of the (long) signal cables n The operation requires Gate ON pulses synchronously with the local time basec

I.Prochazka, Wettzell, May 8, 2009 Detection absolute delay determination n Analysis of the individual contributors u Photon - > electron conversion? << 1 ps u Semiconductor propagation? 1 ps u Avalanche build upOK u Electronic Detection mechanismOK n Avalanche build up1.125 ns +/- ?? n Electronic detection mech.8 ps / 1 mV threshold det. n Electronics propagation5.300 ns +/- 7 ps n Independent comparison checks required

I.Prochazka, Wettzell, May 8, 2009 Contribution to the Wettzell experiment n Joint experiment, April 8-9, 2009 u Optical alignment of SPAD #1 u Routine calibration/SLR on #1 u Reference SPAD #2 installation + calibration n Joint experiment Prague April 10, 2009 u SPAD #1 gating circuit tuning u SPAD #1 tests in Prague indoor cal.facilities n May 7-8, 2009 u Laser pulse length monitoring

I.Prochazka, Wettzell, May 8, 2009 Wettzell laser pulse length n Joint n Instrumental constant determined in Prague using 50 ps laser pulse to be 140 ps n WLRS laser pulse length 184 +/- 10 ps

I.Prochazka, Wettzell, May 8, 2009 Satellite laser ranging chain stability including SPAD detector package Ground target calibration runs K.G.Kirchner, SLR Graz, private communication, May 2009 year

I.Prochazka, Wettzell, May 8, 2009 n WLRS experiment status quo (as far as Prague involvement) u All the specific HW is on site, u The detector(s) and timer are operational on specs u The resulting precision/accuracy goal was has not ben met yet due to unexpected problems with Wettzell hardware (laser pulse) u The individual test indicate the feasibility of the experiment n The development of the ELT detector package is in progress u Version 1.0CMOS, low powerOK u 1.1 Bias voltage / temperature compensation OK u 1.2. Temperature drift compensation in progress u Long term detector stability tests / SLR Graz /OK n We are quite confident, that the ELT experiment is feasible Actual status of SPAD detector development for ELT - ACES mission CONCLUSION – May 8, 2009