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
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
JRA3 Need for high time resolution 1. Rapidly varying astronomical objects 100 Crab Pulsar, OPTIMA, Calar Alto 3.5m, white light 80 Counts/ms 60 40 20 0 0.00 0.05 0.10 0.15 0.20 0.25 0.30 time [s] 2. Rapidly varying earth atmosphere (adaptive optics) Key requirement for high time resolution astronomy: single photon detection and time tagging
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
JRA3 Projected JRA3 spending by technology Avalanche photodiodes Electron multiplied CCDs Avalanche amplified PN CCDs Interfaces & Management 17% 40% 30% 13%
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
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
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 30-100 2 Application tests: - Lucky images : cheating the seeing limit - HTRA: rapidly varying objects - (photon counted spectra)
JRA3 WP5 controllers for EM-CCDs Controller boards, vacuum interface & chip support high voltage clock (WP5)
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
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
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 2008 - thick detection layer (500 μm) near IR response - avalanche amplifier single photon response - AR coatings high QE
JRA3 Avalanche-amplified pn-ccds (WP3) (256+256) 256 pixels Avalanche Amplifiers channel parallel readout ~ 1µs/line 1 ~250 µs s / frame
Avalanche CCD Schematic Cross Section 3 phases pnccd Avalanche Amplifier nmos-fet
JRA3 Avalanche-amplified pn-ccds (WP3)
Entrance Window of Back Illuminated Devices Measured Data Expected (measured/calculated) PDE = Q ew CTE P a
Details of the pnccd Avalanche Readout 71µm 75µm Avalanche Diodes MOSFET Gates Drains
Wafer layout: AApnCCD production 2 Prototype CCDs 264 (256 + 256) pixels 51 µm 51 µm 17 Test CCDs 132 (60 + 60) pixels 51 µm 51 µm 6 Test CCDs 128 (60 + 60) pixels 75 µm 71 µm 8 Test CCDs 132 (86 + 86) pixels 51 µm 51 µm 10 Experimental CCDs Both pixel sizes Readout variants 43 CCDs per Wafer Σ = 516 chips in total
Avalanche CCD Module (in Test) CCD Chip Readout Chip (CAMEX)
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
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
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
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 J1955+26: an optical magnetar
- 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
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
- optical linear polarisation of the Crab pulsar with ~10μsec resolution
Optical Polarisation of the Crab pulsar with ~10msec resolution PA ~ 119 PD ~ 25-35%
MP Zoom to the Peaks optical profile 610 MHz profile 1400 MHz profile MP a bump in PD at phase 0.94
Zoom to ~ 10μsec resolution on the MP MP PA max PA at φ ~ 1.005 min PD at φ ~ 1.000 ( = radio peak) a bend in PA at φ ~ 0.993 ( = optical peak) PD (%)
Observations of Swift J1955+26: the first optical magnetar (?)
Discovery CCD frame of optical transient of GRB070610
Burst (a)
Burst (b)
Fourier Power Density of Bursts QPO signatures at ν~0.11-0.16 Hz P~6-9 sec typicalqposfor SGR/magnetars this transient is likely to be the first detection of an optical magnetar!