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  1. Progress in TES Detector Development forSolar and Astrophysical Research at LMSALRobert Stern, Steve Deiker, Dennis Martínez-Galarce, Adam Rausch, Lawrence Shing (LMSAL*) +NIST, Stanford, Santa Clara U. & LM ATC*Lockheed MartinSolar and Astrophysics LaboratoryLM Advanced Technology Centerstern@lmsal.com

  2. Outline • Some science motivation: why are microcalorimeters useful in solar physics ? • Characteristics of a solar physics X-ray mission concept using TES’s • Laboratory work at LMSAL on TES’s, ADRs • Applicability to astrophysical X-ray instruments • Summary

  3. Exploring Magnetic Reconnectionin the Solar Corona • New instruments needed to investigate dynamics of faint (EM < 1046 cm-3), hot ( > 107 K) material produced by reconnection in microflares and early stages of solar flares • previous flare instruments were mostly based on Bragg Xtal spectrometers with limited (SMM BCS) or no (Yohkoh BCS) imaging capability and very low effective area (0.025-0.1 cm2) • RHESSI (RMC + cooled HP Ge detector) is seeing many such microflaring events, but has limited spectral resolution at low energies ( ~1 keV at 3-10 keV) • High spectral ( R > 1000), spatial, and time resolution of hot (>10MK) plasma (e.g Fe XXV) is required (same Fe K-shell lines as seen in astrophysical sources)

  4. (Liu et al. 2004) RHESSI Fe Line Results • SMEX Launched (finally) in February 2002 • HP Ge (cf. HEAO-3) photon counter with RMC (cf. Minoru Oda, HINOTORI) • designed for hard (> 10keV) X-ray and gamma ray imaging and spectroscopy, but has ~15 cm2 at Fe XXV (6.7 keV) with ~ 1 keV FWHM, ~5 "

  5. Hannah et al. (2004) SOHO Workshop

  6. Explorer Class Mission Concept • Science driven: reconnection physics throughout cycle • 3-8 keV bandpass, < 4 eV energy resolution (R~1700 at Fe XXV 6.7 keV complex) • Combination allows LOS velocity determination to 200 km s-1 and better with centroiding + velocities perpendicular to LOS – 3D velocity field • Grazing Incidence Telescope - Focal Length ~2 m • FOV ~ 2.5 – 3 arc-min with ~few arcsec resolution • Count rate > 103 c/s for event studied (accumulate 10Kct spectrum in 10 sec); time stamping of photon events to sec accuracy

  7. Simulated TES Solar Explorer Spectrum from FeXXV Complex (20 MK) using CHIANTI SMM BCS (~1.25 mA thermal width) “RHESSI”-like microflare / 4 eV FWHM

  8. Key Technology Developments Needed • Up till now, most technology for X-ray TES driven by, e.g., Constellation-X, NeXT and XEUS (10-50 m focal lengths) • Small solar payload with F.L ~ 2 m  needs effective pixels of 10-20 m or so • Smaller effective pixels also help larger missions such as RAM (Reconnection And Microscale Mission) • Solar payloads need large number of spatial resolution elements to cover active region with high angular resolution • will likely require “tiled” or modular focal plane • High countrate ( kcts/sec) in microflare/flare region to accumulate spectrum quickly • Low mass cryocooler + Adiabatic Demagnetization Refrigerator (ADR) with long life

  9. Current Program of TES Research at LMSAL • Operate NIST-supplied devices (single pixel on NIST array) • Fe55 X-ray spectrum from 1st gen setup; 2nd gen in progress • Recent SR&T awards (Solar & Heliospheric) from NASA • Position Sensitive X-ray Strip Detectors (with NIST, SU) • Al:Mn Magnetically Insensitive TES (with Santa Clara, SU) • Solar TES Rocket (lower energies ~ 1 keV) – with SU, LLNL • New initiative: rocket ADR adapted for TES/SQUID readout (with LMATC Thermal Group, U. Wisconsin) • Pending: collaboration with MIT (Tali Figueroa), GSFC, U. Wisc on X-ray imaging TES rocket payload • Current goals: solar X-ray TES Explorer; Reconnection and Microscale Mission (long term)

  10. Key Collaborators in TES Instrumentation • NIST (TES’s, SQUIDs, Strip Detectors) • Kent Irwin, Gene Hilton, Joel Ullom, Randy Doriese • Stanford (TES principles, Al:Mn, Lab ADR experience) • Blas Cabrera, Paul Brink, Steve Leman, T.J. Bay • Santa Clara University (Al:Mn devices) • Betty Young • University of Wisconsin (Rocket ADR) • Dan McCammon • Lockheed Martin Advanced Technology Center Thermal Sciences Department (cryogenic technology, rocket ADR project) • Ted Nast, Dean Read

  11. Mn K-α and K-β. Measured resolution is 15.5 eV FWHM Fe55 Spectrum With 1st Generation Base Stage (late 2005) Single pixel achieved 2.4 eV FWHM (at NIST) • Need improved LMSAL base stage/noise reduction to separate Kα1, Kα2 LMSAL Lab Base Stage

  12. 2nd Generation Base Stage (under construction) Nb shield 1st stage SQUID slots (4) • Improvements: • Full Nb shield, • Axis of field-canceling coil perpendicular to axis of SQuID coils • Accomodates thermometry near TES, • Easier bonder access • Decreased size / weight. TES Slot

  13. NIST/LMSAL Strip Detector Concept Prototype Array • 32 parallel 10m wide strips each 320m long with ~ 10m position resolution (32  x 32  at 2m FL) MUXed at each end

  14. Strip Detector Test Wafer (LMSAL/NIST Grant(s) from NASA) with Pd layer (6/06)

  15. Manganese-doped Aluminum TES (NASA Grant with SU and SCU) Alternative to bi-layers: • Simplicity of fabrication. • Low noise • comparable to bi-layers • Design flexibility (not limited in thickness). • Apparent insensitivity to magnetic fields.

  16. Lockheed Martin Rocket ADR re-design (collab with U. Wisc.) Modify Design and Construct 3-D Solid Model Original U. of Wisc.design McCammon et al 2002 Low magnetic field required for TES operation

  17. Full 8.5 A => 4 T in core Operating ~ 150 mA => 700 G in core Passive Shields: Van. Perm. or Cryoperm Detector plate ≤ 3 G at detector plane Magnetic Field Modeling B-field at detector ≤ 0.05 G • Status: • 2nd iteration of design; FEM dynamics analysis to be re-run • Order and test magnet/shield in CY 2006 • Modify with additional shielding/bucking coil if required

  18. Astrophysics Applicability • Strip detectors • Short focal length telescopes • Multiplex capability results in fewer wires/resolution element • Al:Mn • detector thickness constraint removed • potential to significantly reduce magnetic shield requirements • Prototype (Rocket) ADR • new design will provide flight test of TES/SQUID operation

  19. Summary • LMSAL (with considerable help from NIST/SU/ Wisc./SCU) is pursuing a vigorous program of TES-related research focused on solar physics (with potential applicability to astrophysics) • Laboratory work (begun ~ 2 ½ yrs ago) is close to achieving noise goals for single-pixel devices • Position-sensitive strip detectors have been fabricated and are about to begin testing at NIST and LMSAL. • Al:Mn detector work with SCU/SU has begun • ADR Prototype design for TES solar rocket is nearly complete; magnet/shielding tests to begin this year

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