Ivan ProcházkaJosef Blažej, Jan Kodet

presented at :

ELT meeting CTU in Prague, December 8, 2010

Czech Technical University in Prague, Czech Republic

Status of the European Laser Timing ELT Detector package

I.Prochazka, ACES IWG Observatoire de Paris, Paris, July 9, 2009

Principal participants and contributors Luigi Cacciapuoti, ESTEC, The Netherlands

ESA coordination

Urs Hugentobler, Tech. Univ. Munich, Germanyspace geodesy

Pierre Lauber, TU Munich, GermanySatellite Laser Station Wettzell

Ivan Prochazka, Czech Tech.University in PragueInstrument Science coordinator

Wolfgang Schaefer, TimeTech, Germanytiming devices

Ulrich Schreiber, Tech.Univ.Munich & BKG GermanyData Analysis Coordinator

I.Prochazka, ACES IWG Observatoire de Paris, Paris, July 9, 2009

ACTIVITIES in SPACE RELATED PROJECTS Czech Technical University in Prague

new ESA member since 2008

Satellite Laser Ranging since 1972

Picosecond Detector Technology since 1984

Planetary altimetry & LIDAR since 1989

Picosecond Event Timing since 1996

I.Prochazka, ACES IWG Observatoire de Paris, Paris, July 9, 2009

Satellite Laser Ranging Since 1972, world 3rd country

I.Prochazka, ACES IWG Observatoire de Paris, Paris, July 9, 2009

Satellite Laser Ranging operation principle

pulsed optical radar

range precision1 .. 3 / mm / shot

operational range0 - 30 ooo km

25 installations onon 5 continents

Graz, Austria

I.Prochazka, ACES IWG Observatoire de Paris, Paris, July 9, 2009

Single Photon Detectors made by CTU

Si ,200 um,TE3 cooled, vacuum GaAs messa GaAsP, 350 um

Detector for LTT China Complete detector packages

130 mm

I.Prochazka, ACES IWG Observatoire de Paris, Paris, July 9, 2009

Detectors for Space Applications

CTU Prague & IKI Moscow

MARS 92 (USSR / Russia, 1992-96) Photon counting laser rangefinderMars baloon altimetry

NASA Mars Polar Lander, (USA, 1998) Photon counting LIDAR,Mars surface atmospheric studies

S.P.Pershin et all, IKI Russia

I.Prochazka, ACES IWG Observatoire de Paris, Paris, July 9, 2009

Laser Time Transfer in Space

LTT – China since April 2007China Compass-M1 / Beidou

T2L2 CNES - France since June 2008 JASON-2

Time and frequency transferusing ps laser pulses in space

Relying on available technologyand ground segment Satellite Laser Ranging

Superb precision and accuracy

Navigation, deep-space, fundamental physics…

E.Samain

I.Prochazka, ACES IWG Observatoire de Paris, Paris, July 9, 2009

“H maser in space”, ’94, France + Russia + Praguecanceled

LTT China + PragueCompass M1 Beidou, (operational since Aug. 2007)

T2L2 E. Samain et alACES -> Miriade -> Jason 2 (operational sine June 2008)

ELT proposed by CTU Prague and TU Munich, June 2008I.Prochazka, U.Schreiber

Investigators Working Group established Dec. 2008

Ground tests (Prague, Munich) started Dec. 2008

European Laser Time Transfer ELTHistory review

I.Prochazka, ACES IWG Observatoire de Paris, Paris, July 9, 2009

“H maser in space” single photon detection, 100 um SPAD, gated

LTT China single photon detection, 25 um SPAD, not gated + very simple design and construction - modest precision and accuracy ~30 ps - synchronous operation needed /solved/

T2L2 multiphoton, time walk corrected, asynchronous + extremely high precision, asynchronous operation - very high complexity, systematic errors issue

ELT single photon det.,100 um SPAD, gated, temp. comp. + high precision AND accuracy, simple, compact

+/- synchronous operation needed /solved/

Laser Time Transfer - Concepts

I.Prochazka, ACES IWG Observatoire de Paris, Paris, July 9, 2009

ELT space optical part conceptLaser retro array, GFZ concept

existing, approved

Detector input aperture

Photon detection chip

Detector optics

NO optical components alignment Very simple and rugged

I.Prochazka, ACES IWG Observatoire de Paris, Paris, July 9, 2009

Specific accomodation requirements # 1 Field of view of the optical assembly (retro + receiver)

+ / - 60 degrees from nadir un-obscured view

Detector temperature range - IDEAL case any temperature -50..+30 C, stable +/- 2 C- the WORST case range -50…+50 C

Cooling of optical receiver- total heat generated 0.15 W to 5 W depends on configuration- amount of heat depends on detector temperature range (the excess heat is used to temp.stabilize the receiver, if needed)

= > KEY PROBLEM AREA – THERMAL CHANGES of ELT assempbly

I.Prochazka, ACES IWG Observatoire de Paris, Paris, July 9, 2009

Wettzell ground demonstration experimentDecember 2008 – May 2009

Ground demonstration of the entire timing performance via a space target and SLR combined

I.Prochazka, ACES IWG Observatoire de Paris, Paris, July 9, 2009

Wettzell ground demonstration experimentDecember 2008 – May 2009

I.Prochazka, ACES IWG Observatoire de Paris, Paris, July 9, 2009

Wettzell ground demonstration experiment

The experiment feasibility was demonstrated in a completeground experiment

The final precision was impaired by in-appropriate WLRS laser pulse length problem. ( about 230ps instead of 80 ps).

The indoor tests indicate, that for shorted laser pulses the desiredprecision might be reached.

I.Prochazka, ACES IWG Observatoire de Paris, Paris, July 9, 2009

Precision and accuracy goalsELT detector assembly

Single photon signals only = > no biasesassured by useful data rate ( < 20%)

Detection delay jitter < 30 ps rmsresulting in 3 ps / 100 s

Detection delay stability +/- 3 ps

I.Prochazka, ACES IWG Observatoire de Paris, Paris, July 9, 2009

Prague group activities - detector

Detector package for WLRS # 1 (delivered) # 2 (reference)

Development of the ELT package Version 1.0 CMOS, very low power OK 1.1 Bias voltage / temperature compensation OK 1.2. Temperature drift compensation in progress

Detection absolute delay determination promissing

Contribution to WLRS experiment

Long term stability tests / SLR Graz / OK

I.Prochazka, ACES IWG Observatoire de Paris, Paris, July 9, 2009

Development of the ELT packageVersion 1.0 CMOS, low power

CMOS version, low power < 50 mW (detector) < 500 mW (power s.)

Ver. 1.1. Bias voltage / temperature compensation OKdetector bias controlled within the temp. range of -50… +50 C

I.Prochazka, ACES IWG Observatoire de Paris, Paris, July 9, 2009

Development of the ELT packageVersion 1.1. CMOS, low power

Detection delay dependence~ 60 ps / V at 2.5 V ab

= > +/- 3 ps delay stability using bias stabilizing circuit

Timing jitter < 30 ps overallfor > 1.5 V above48 ps laser pulse

I.Prochazka, ACES IWG Observatoire de Paris, Paris, July 9, 2009

Detection absolute delay determination

Analysis of the individual contributors Photon - > electron conversion ? << 1 ps Semiconductor propagation ? 1 ps Avalanche build up OK Electronic Detection mechanism OK

Avalanche build up 1.125 ns +/- ?? Electronic detection mech. 8 ps / 1 mV threshold det. Electronics propagation 5.300 ns +/- 7 ps

Independent comparison checks required

I.Prochazka, ACES IWG Observatoire de Paris, Paris, July 9, 2009

Detector package operation in extreme background regime

Operational up to 200 Mc /s of background photon flux(up to 50 Mc/s are expected)

Gated 100 ns beforesimulation of ELT daylight operation

Timing jitter < 25 ps rms overall using 48 ps laser pulse

Detection delay stability +/- 4psover entire background dynamical range

I.Prochazka, ACES IWG Observatoire de Paris, Paris, July 9, 2009

Timing stability of the photon counting chainGraz SLR station, SPAD detector

Graz Routine Calibrations 2009/050 - 2009/112Drift due to Stop Pulse / Coax Cable / Temp Coeff

129210129215129220129225129230129235129240129245129250129255129260

-5 0 5 10 15 20 25

Air Temperature [°C]

CA

L Va

lue

[ps]

Series1

NOTE system STABILITY ~ 2.5 ps r.m.s. Cable temp.drift ~ 1 ps / K

= > The /cables/ temperature issue is critical for timing stabilityCables ~ meters are expected to be locate outside .

I.Prochazka, ACES IWG Observatoire de Paris, Paris, July 9, 2009

Development of the ELT packageVersion 1.2. CMOS, temperature drift compensation

The new detector electronics is automatically compensating the temperature variations of the detector electronic circuit delayincluding the delay temperature drift of the (long) signal cables

The operation requires Gate ON pulses synchronously with the local time scale

I.Prochazka, ACES IWG Observatoire de Paris, Paris, July 9, 2009

WLRS experiment The experiment indicated the feasibility of the ELT The resulting precision/accuracy goal was has not been met yet due to

unexpected problems with Wettzell hardware (laser pulse) The experiment continues

The development of the ELT detector package in Prague Version 1.0 CMOS, low power OK 1.1 Bias voltage / temperature compensation OK 1.2. Temperature drift compensation in progress Long term detector stability tests / SLR Graz / OK

Actual status of SPAD detector development for ELT-ACES CONCLUSION