JRA3: Technology development for high-time-resolution astronomy

Transcription

1 JRA3: Technology development for high-time-resolution astronomy ( HTRA: ~ 10 ms -- 1μs ) Objectives: - To develop the most promising technologies for HTRA - Assess relative strengths/areas of application in astronomy Gottfried Kanbach, MPE, Garching & Henk Spruit, MPA, Garching

2 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 Applied Technology Center, Edinburgh Landessternwarte Heidelberg Max-Planck-Institut für Astrophysik European Southern Observatory

3 JRA3 Need for high time resolution 1. Rapidly varying astronomical objects 100 Crab Pulsar, OPTIMA, Calar Alto 3.5m, white light 80 Counts/ms time [s] 2. Rapidly varying earth atmosphere (adaptive optics) Key requirement for high time resolution astronomy: single photon detection and time tagging

4 JRA3 Contractors and workpackages WP4 Avalanche photodiode arrays WP2 EM-CCDs (L3CCDs) WP3 Avalanche amplified pn-ccds WP5 CCD controllers WP6 Software WP7 Testbeds WP1 Management NUIG Sheffield Warwick UKATC MPG/MPE ESO IoA, NOTSA MPG/MPA, LSW

5 JRA3 Projected JRA3 spending by technology Avalanche photodiodes Electron multiplied CCDs Avalanche amplified PN CCDs Interfaces & Management 17% 40% 30% 13%

6 JRA3 WP4 APD-array development National University of Ireland in collaboration with University College Cork Single detectors in use for HTRA and AO spatially separated array elements (avoid crosstalk) - to be fed with lenslet arrays or fibers

7 JRA3 APD arrays (WP4) Summary and perspective of APD technology - mature technology but still with limitations w.r.t. cross-talk, dark current, non-uniformity. New approaches: APD pixel arrays Si-PMTs - still the technology for highest time resolution & high QE

8 JRA3 L3CCDs (EM-CCDs) WP2, WP5, WP7 Conventional CCDs: spurious electrons on readout EM : On-chip electron multiplication Available now commercially (E2V, TI) JRA3 activities: 1 Controller development for high time resolution applications - up to 60 Mpix/s - reduction of clock induced spurious charges by factors Application tests: - Lucky images : cheating the seeing limit - HTRA: rapidly varying objects - (photon counted spectra)

9 JRA3 WP5 controllers for EM-CCDs Controller boards, vacuum interface & chip support high voltage clock (WP5)

10 JRA3 Lucky imaging C. MacKay, UCAM, 200 inch Palomar, 2007 E2V EM-CCD + fast controller (WP5,6,2) M13 all frames 10% best frames Cat s Eye

11 JRA3 Summary and perspective for EM-CCDs Best currently available low light level 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

12 JRA3 / WP3: Avalanche-amplified pn-ccds Alternative silicon technology for HTRA Based on developments of pnccds at the semiconductor laboratory of the MPG (fast X-ray imaging) Devices for the optical range with single photon sensitivity initiated by JRA3: Technology elements produced and tested (Aug 2007) Readout and DAQ tested with classical pnccd in astronomical observations (Aug 2007) Prototype AApnCCD device by end of thick detection layer (500 μm) near IR response - avalanche amplifier single photon response - AR coatings high QE

13 JRA3 Avalanche-amplified pn-ccds (WP3) ( ) 256 pixels Avalanche Amplifiers channel parallel readout ~ 1µs/line 1 ~250 µs s / frame

14 Avalanche CCD Schematic Cross Section 3 phases pnccd Avalanche Amplifier nmos-fet

15 JRA3 Avalanche-amplified pn-ccds (WP3)

16 Entrance Window of Back Illuminated Devices Measured Data Expected (measured/calculated) PDE = Q ew CTE P a

17 Details of the pnccd Avalanche Readout 71µm 75µm Avalanche Diodes MOSFET Gates Drains

18 Wafer layout: AApnCCD production 2 Prototype CCDs 264 ( ) pixels 51 µm 51 µm 17 Test CCDs 132 ( ) pixels 51 µm 51 µm 6 Test CCDs 128 ( ) pixels 75 µm 71 µm 8 Test CCDs 132 ( ) pixels 51 µm 51 µm 10 Experimental CCDs Both pixel sizes Readout variants 43 CCDs per Wafer Σ = 516 chips in total

19 Avalanche CCD Module (in Test) CCD Chip Readout Chip (CAMEX)

20 JRA3 Status of AApnCCD Prototype Production and Tests 15 cm Wafer High-Ohmic n-silicon Very Complex Process, Compatible with BID-SiPM Devices (10 Implantation Steps, Double Sided Processing) One Year Production Time, Finished in August 2008 Tests on Wafer Level successful Leakage Current < 400 pa/cm 2 Expected Breakdown Voltage: 42 V NMOS-FET Works as Simulated CCD Tests in the laboratory next month

21 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

22 JRA3 Summary and perspective AApnCCDs represents next generation electron-multiplied CCD technology - photon counting accuracy - wavelength range - IR sensitivity - time resolution (<1 ms) development on schedule full-scale CCD out of the oven, functional tests ongoing prototype device and controller expected by end 2008

23 Some recent highlights using HTRA techniques: - the Crab pulsar observed with a pnccd - optical linear polarisation of the Crab pulsar with ~10μsec resolution - observations of Swift J : an optical magnetar

24 - the Crab pulsar observed with a pnccd pnccd array, ceramic board, cooling mask vacuum interface and feedthrough outside the vacuum CCD pulse driver voltage and current control

25 Exposure of 16 sec with ~600 fps. The data stream was folded with the Crab period and is displayed in 9 phase bins in the movie

26 - optical linear polarisation of the Crab pulsar with ~10μsec resolution

27 Optical Polarisation of the Crab pulsar with ~10msec resolution PA ~ 119 PD ~ 25-35%

28 MP Zoom to the Peaks optical profile 610 MHz profile 1400 MHz profile MP a bump in PD at phase 0.94

29 Zoom to ~ 10μsec resolution on the MP MP PA max PA at φ ~ min PD at φ ~ ( = radio peak) a bend in PA at φ ~ ( = optical peak) PD (%)

30 Observations of Swift J : the first optical magnetar (?)

31 Discovery CCD frame of optical transient of GRB070610

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34 Burst (a)

35 Burst (b)

36 Fourier Power Density of Bursts QPO signatures at ν~ Hz P~6-9 sec typicalqposfor SGR/magnetars this transient is likely to be the first detection of an optical magnetar!