Science Objectives. Test Inflationary models, particle physics at the highest energies

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1 Cryogenic Detectors for Astrophysics Far-IR, Submillimeter, and CMB Harvey Moseley NASA/GSFC

2 Science Objectives Test Inflationary models, particle physics at the highest energies Inflation Inflation should leave imprint in polarization of CMB (B-mode polarization), its magnitude related to energy scale of inflation. Test models for structure formation in the early universe GalaxyGalaxy clustering and correlations driven by dark matter 4/6/2006 SNIC Moseley- 2

3 CMB polarization is a unique probe of Inflation CMBPOL* 1000 detectors 1.0 deg. Beam CMBPOL* 2000 detectors 0.1 deg. Beam *2 lines span foreground uncertainty 4/6/2006 SNIC Moseley- 3

4 WMAP Results Important Step in Understanding CMB Polarization WMAP has detected E-E mode polarization at large angles, and sets significant limits on B-B Mode Spectral slope is significant less than 1; theorists see smoking gun of inflation? Resolution will require B-Mode measurement 4/6/2006 SNIC Moseley- 4

5 The High z Universe is Easily Observed at Sub-mm and mm The Inverse K-correction K results in very small variation of galaxy brightness with redshift. Multicolor imaging or spectroscopy are essential for sorting the sources by z Devlin 4/6/2006 SNIC Moseley- 5

6 Submillimeter/MM Surveys Show Evolution of Early Universe Surveys can determine star formation rate in the early universe. With adequate spectroscopy, can be used to track growth of structure Smail et al. Eisenstein et al. 4/6/2006 SNIC Moseley- 6

7 Observing Facilities 4/6/2006 SNIC Moseley- 7

8 Sensitivity Thermal detectors operating at 0.1 K can reach background limit with margin over the peak of the CMB Cryo cooling to 0.1 K is well developed Raw sensitivity is easily reached by semiconducting and TES bolometers STJs,, KIDS, can, in principle, reach similar sensitivity at 0.3 K QuickTime and a TIFF (LZW) decompressor are needed to see this picture. 4/6/2006 SNIC Moseley- 8

9 Both Objectives Require Large Arrays of High Performance Detectors Sensitivity limits set by photon statistics from cosmic backgrounds. Present generation of bolometers operating near 0.1 K can reach background limits for imaging Both objectives require large arrays of such detectors to do large area surveys in practical times CMBPol -> > ~ 1000 channels of background limited detectors in a high performance polarimeter SMM Galaxy survey ~ 1000 s s of detectors for imaging, higher sensitivity detectors for spectroscopy; spectroscopy detectors need n significant development 4/6/2006 SNIC Moseley- 9

10 History Evolution of GSFC Bolometers COBE-FIRAS 1 pixel, handmade mid 1980 s QuickTime and a TIFF (Uncompressed) decompressor are needed to see this picture. KAO spectrometer 24 pixels, handmade 1987 SHARC I 24 pixels, micromachined early 1990 s 4/6/2006 SNIC Moseley- 10

11 History Examples of Detector Arrays Spitzer/MIPS 100 Element Flight Array (U. of Arizona) 160µm SOFIA/HAWC 384 Element Flight Array (GSFC) µm Herschel/SPIRE 144 Element Prototype Array (Caltech/JPL) µm 4/6/2006 SNIC Moseley- 11

12 Motivation Background, Sensitivity Beam Formation Focal Plane Utilization Readout, Format Detector Design System Implementation Simultaneous Spectral Coverage Observing Strategy Temporal Response, System 1/f Noise 4/6/2006 SNIC Moseley- 12

13 Development Process The Path to Kilopixel Arrays and Beyond Choice of Architecture Radiation Coupling Level of integration EM Modeling of coupling, filtering, transmission, detection Thermal/Mechanical design of detector Mather (1982, 1984), Irwin (1996 ) Fabrication and test of components Integration Test of system 4/6/2006 SNIC Moseley- 13

14 Microstrip Components for CMBPol Light coupling method: On-chip modulation: NASA GSFC Platelet feed horn & planar OMT light collection concept (above). Test of stacked thru-wafer Si waveguides (top right). Membranes over Si waveguides (right). Predicted behavior (left) and photo (right) of prototype millimeter-wave microstrip switch device based on variable inductance of Josephson junction. Laboratory tests with VNA: Microstrip bandpass filters: Chip with 100 GHz waveguide probe antennas (above) fits in Bandpass filters designed for split block (top right). Package three measurement bands with with K-connectors allows tests up low high frequency leakage. to 40 GHz (right). 4/6/2006 SNIC Moseley- 14

15 Mechanical Characterization Mechanical-Amplifier device for measurement of mechanical properties of detector materials (Si Nitride in this case) 4/6/2006 SNIC Moseley- 15

16 WR02.2 Platelet Feed Array: Return Loss for elements sampled better than 20 db across test band E. Wollack, et al. - NASA/GSFC 4/6/2006 SNIC Moseley- 16

17 Movie of the computed current density J y (x,y,t): QuickTime and a Video decompressor are needed to see this picture. x-axis, along the slots y-axis, perpendicular to slots (slots are at y = ±0.25, -0.5 < x < 0.5, and have width 0.04) 4/6/2006 SNIC Moseley- 17

18 VNA/Microstrip Test Facility Waveguide/Microstrip Probe Superconducting Test Capability Rapid characterization with VNA 4/6/2006 SNIC Moseley- 18

19 Double Split-End Quarter-wave SIR Filter NASA GSFC REFERNCE: U-yen, K., Wollack, E.J., Doiron, T., Papapolymerou, J., Laskar, J., A Planar Bandpass Filter Design with Extended Rejection Bandwidth Using Double Split-end Stepped Impedance Resonators, 2006, IEEE Microwave Methods and Techniques, Vol. 55, No. 3, pp Normal metal quarter-wave SIR (Stepped Impedance Resonator) filter design prototype with large stop band. Frequency response of db S 21 (solid line) and db S 11 (dash line) of filter with 3 transmission zeros placed around the lowest spurious us frequency (at 5.65GHz) and 4 transmission zeros place around the second lowest frequency y (at 8.47GHz). 4/6/2006 SNIC Moseley- 19

20 Characterization SQUID Amplifiers SQUID amplifiers are well-matched to TES detectors Operate at detector temperature Low noise makes multiplexing feasible 4/6/2006 SNIC Moseley- 20

21 GSFC-NIST Collaboration NASA GSFC GSFC NIST SQUIDs Detector Electronics Instrument Remote Control File Edit View Tools Visualizations Help Status Observing Instrument Telescope Instrument Cryogenics Secondary Mirror Pointing File Edit Image Options Apertures Help Temperatures Cold Shield 4 K Detector 350 mk Computers Housekeeping Detector Master Telescope Temperatures Cavity 230 K Primary 227 K Property Chop amplitude Chop angle Chop mode Chop frequency Offset Apply Changes Integration Property Chop cycles per frame Integration time per nod Number of nod pairs Start Position Value Units 0 arcsec 20 degrees external ft 4 Hz 0 arcsec Revert Changes Value Units 4 10 sec , RA, DAC Aircraft R R L L Mosaic Image File Edit Image Options Apertures Help Nods Complete: 4 Remaining: 55 Observation Nods Complete: 4 Remaining: 55 Image Software Science 4/6/2006 SNIC Moseley- 21

22 Integrating Detector to SQUID Mux Following the SCUBA II development, we have extended the bump bonding to allow one-sided bumps to thin substrates 4/6/2006 SNIC Moseley- 22

23 Transition Edge Sensor Bolometers One highly credible approach to meeting future pixel count and sensitivity requirements is with superconducting transition edge sensor (TES) bolometers C1R C1R Temperature (K) 4/6/2006 SNIC Moseley- 23

24 Characterization Detector I-V I V Curves Normal region at high voltage provides ohmic definition of zero point S/C region is hyperbolic 4/6/2006 SNIC Moseley- 24

25 Characterization Detector Noise Noise very close to theoretical limit! 4/6/2006 SNIC Moseley- 25

26 TES Pop-up Bolometer Array 1 x 32 TES arrays have been produced for ACT; device characterization in progress. 4/6/2006 SNIC Moseley- 26

27 ACT - Atacama Cosmology Telescope U. Wales - Cardiff, U. Colorado, Columbia, CUNY, Haverford, NASA/GSFC, NIST, U. Penn., Princeton, Rutgers, UBC, U. de Catolica, U. Mass. - Amherst, U. Toronto NASA GSFC Observations: CMB: l>1000 Cluster (SZ, KSZ X-rays, & optical) Diffuse SZ OV Lensing ACT camera will consist of element arrays from GSFC Science: Growth of structure Eqn. of state Neutrino mass Ionization history Power spectrum 1.4 SZ Simulation MBAC on ACT PLANCK 4/6/2006 SNIC Moseley- 27

28 GBT 3mm Camera U.Pennsylvania,, NASA/GSFC, NIST, NRAO, U. Wales - Cardiff First NRAO bolometer camera Sensitivity ~500µJy in 1 s Great for extragalactic surveys - very sensitive Can do amazing Galactic science - high resolution NASA GSFC 3.3mm wavelength, 8x8 array Features 64 pixels = 32 x 32 FOV, with 8 8 resolution 4/6/2006 SNIC Moseley- 28

29 Goddard/IRAM 2mm Camera GISMO NASA/GSFC,, IRAM, NIST Hybrid bolometer/readout camera Sensitivity ~1mJy in 1 min on 10 sq. arcmin FOV Great for extragalactic followup - high-z z instrument Can do amazing Galactic science - rapid mapping QuickTime and a TIFF (Uncompressed) decompressor are needed to see this picture. NASA GSFC 2mm wavelength, 8x16 array Features 128 pixels = 2.2 x 4.4 FOV, with 17 resolution Above: IRAM 30m telescope Below: enlargement of pixels SZ cluster: high res image in 1 night 8x8 prototype array 4/6/2006 SNIC Moseley- 29

30 Summary Highly integrated arrays of kilopixels of background limited detectors are required to address the studies of CMB polarization and to characterize cterize the epoch of initial star formation Elements of the system design are generally understood well enough to optimize analytically and produce the desired component Exceptions: TES noise not understood in a fundamental way Thermal conductance in small structures still determined by iteration Overall thermal/mechanical design must be carefully done Completing this next generation of detector is within technical reach Build now, or wait for perfection? Large engineering project, needs concerted effort 4/6/2006 SNIC Moseley- 30