JRA3:
Technology development
for high-time-resolution astronomy
( HTRA: ~ 100 ms -- 1μs )
- To develop the most promising
technologies for HTRA
- Assess relative strengths/areas of application
in astronomy
Corfu 10/9/07
JRA3
- Indicative budget 1.2 M€
- 3 main technology WPs
- 4 ‘connective tissue’ WPs
Partners
Max-Planck-Institut für Extraterrestrische Physik
Institute of Astronomy, Cambridge
National University of Ireland, Galway
University of Warwick
Sheffield University
UK Astronomy Technology Centre, Edinburgh
Landessternwarte Heidelberg
Max-Planck-Institut für Astrophysik
European Southern Observatory
Corfu 10/9/07
JRA3
Need for high time resolution
1. Rapidly varying astronomical objects
1
2
3s
GX 339-4 13/5/04 FORS2 HITI
2. Rapidly varying earth atmosphere
(adaptive optics)
Key requirement for high time resolution astronomy:
single photon detection
Corfu 10/9/07
JRA3
Contractors and workpackages
WP4 Avalanche photodiode arrays
WP2 EM-CCDs (L3CCDs)
WP3 Avalanche amplified pn-CCDs
WP5
WP6
WP7
WP1
CCD controllers
Software
Testbeds
Management
NUIG
Sheffield
Warwick
UKATC
MPG/MPE
ESO
IoA, NOTSA
MPG/MPA, LSW
Corfu 10/9/07
JRA3
Projected JRA3 spending by technology
Avalanche photodiodes
17%
~ 1985
Electron multiplied CCDs
40%
2004
Avalanche amplified PN CCDs30%
2008
‘connective tissue’
13%
Corfu 10/9/07
JRA3
WP4 APD-array development
National University of Ireland
in collaboration with University College Cork
Single detectors in use for HTRA and AO
Array elements have
to be spatially separated
(crosstalk)
- to be fed with
- lenslet arrays or
- fibers
Corfu 10/9/07
JRA3
APD arrays (WP4)
On-chip arrays
nFibre fed APD array
¨Fibres epoxied by UV curing to APD devices
¨Elimination of cross talk issue due to
¨separated APD elements
Individual fibres aligned on to
APD dies in ceramic packages
Corfu 10/9/07
JRA3
APD arrays (WP4)
Summary and perspective APD technology
- known technology
- limitations: cross-talk,
dark current
non-uniformity.
- close to its technological limit
- CCD-based technologies encroaching
on its territory
but ...
- still the only technology for highest
time resolution
Corfu 10/9/07
JRA3
L3CCDs (EM-CCDs) WP2, WP5, WP7
● Conventional CCDs: spurious electrons on readout
● ‘EM’: On-chip electron multiplication
● Available now (E2V, TI)
● JRA3 activities:
1 Controller development for high time resolution applications
- up to 60 Mpix/s
2 Application tests:
- ‘Lucky images’: cheating the seeing limit
- HTRA: rapidly varying objects
- (photon counted spectra)
Corfu 10/9/07
JRA3
‘Lucky images’
E2V EM-CCD
+
fast controller
(WP5,6,2)
M13
Cat’s Eye
all frames
10% best frames
Corfu 10/9/07
JRA3
‘Lucky images’
pulsar in crab nebula
P=30 ms
exposures 2 ms
Corfu 10/9/07
Spectra with single-photon detection
Corfu 10/9/07
JRA3
WP5 controllers for EM-CCDs
Controller boards, vacuum interface & chip support
Corfu 10/9/07
JRA3
Summary and perspective EM-CCDs
● Best currently available technology
● Advances in controllers & data processing
technology
● Shows the potential of photon counting CCDs for
- high time resolution observations
- angular resolution improvement by ‘lucky imaging’
- wavefront sensors for AO
● technology still developing rapidly
Corfu 10/9/07
JRA3
Avalanche-amplified pn-sensors (AA-pn)
● Alternative silicon technology for same purpose
● Developed at the semiconductor laboratory of
the MPG,
● Initiated by JRA3
● Technology elements produced and tested (Aug 2007)
● Prototype device by end of 2008
● elements:
- thick detection layer (0.5mm)
- avalanche amplifier
- AR coatings
Corfu 10/9/07
JRA3
Avalanche-amplified pn-CCDs (WP3)
Corfu 10/9/07
JRA3
Avalanche-amplified pn-CCDs (WP3)
Corfu 10/9/07
JRA3
Avalanche-amplified pn-CCDs (WP3)
Corfu 10/9/07
JRA3
Avalanche-amplified pn-CCDs (WP3)
Differences ↔ E2V EM-CCD
1.
Parallel readout + slower clock
→ lower readout noise
→ lower amplification factor →
● higher dynamic range and
● no internally generated photons
2. Deep depletion layer →
● near-IR wavelength sensitivity
3. AR coating technology:
● broader wavelength range
Corfu 10/9/07
JRA3
Avalanche-amplified pn-CCDs (WP3)
Corfu 10/9/07
JRA3
Avalanche-amplified pn-CCDs (WP3)
Corfu 10/9/07
JRA3
Summary and perspective AA-pn CCDs
● represents next generation electron-multiplied CCD
technology
- photon counting accuracy
- wavelength range
- IR sensitivity
- time resolution (<1 ms)
● development on schedule
● full-scale CCD currently ‘in the oven’, functional tests mid2008
● prototype device and controller expected by end 2008
Corfu 10/9/07
JRA3
‘connective tissue’
- camera head development (WP7, completed)
- higher level software interfaces (WP6, under
construction)
- management (WP1)
Corfu 10/9/07
JRA3
UKATC high voltage clock (WP5)
Corfu 10/9/07
JRA3
WP 7 Cooled camera head (in ESO
cryostat)
Corfu 10/9/07
JRA3
Management
Main events since start of contract
- Transfer of management from LSW Heidelberg to MPA (July
05)
- Redefinition of technology contribution MPE (Feb 05)
- Common hardware platform for comparison of technologies
replaced by software procedure (Feb 05)
- Definitive finance plan JRA3 approved by OPTICON board
(Oct 05)
Status August
- 95% of work on track
- Technologies successful beyond expectation
- Major innovations achieved in high time resolution CCDs
Corfu 10/9/07
JRA3
Miles and deliverables (as of Aug 2007)
WP1
WP2
WP3
WP4
WP5
WP6
WP7
WP8
achieved/delivered
M1, M2, M3
M1, M2, D1
M1, M2, D1
M1
M1,M2,M3,D1
M1
M1, D1
M1
remaining
D2
D2
M3, D2
M2, D2
D2
D1
completed
D1
Corfu 10/9/07
JRA3
Corfu 10/9/07