Adiabatic Demagnetization Refrigerator Field Mapping and Shielding Models for a 70 mK Superconducting Transition Edge Sensor Array and Associated Electronics

Journal Article · Thu Apr 27 00:00:00 EDT 2006 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.2202508· OSTI ID:20800230

Ladner, D R ^[1]; Martinez-Galarce, D S ^[2]; McCammon, D ^[3]

---

1. N-Science Corporation, Arvada, CO 80002 (United States)
2. Lockheed Martin Solar and Astrophysics Laboratory, Palo Alto, CA 94304 (United States)
3. University of Wisconsin, Madison, WI 53706 (United States)

An X-ray detection instrument to be flown on a sounding rocket experiment (the Advanced Technology Solar Spectroscopic Imager -- ATSSI) for solar physics observations is being developed by the Lockheed Martin Solar and Astrophysics Laboratory (LMSAL). The detector is a novel class of microcalorimeter, a superconducting Transition-Edge Sensor (TES), that coupled with associated SQUID and feedback electronics requires high temperature stability at {approx}70 mK to resolve the energy of absorbed X-ray photons emitted from the solar corona. The cooling system incorporates an existing Adiabatic Demagnetization Refrigerator (ADR) developed at the University of Wisconsin (UW), which was previously flown to study the diffuse cosmic X-ray background. The Si thermistor detectors for that project required 130 K shielded JFET electronic components that are much less sensitive to the external field of the ADR solenoid than are the 1st ({approx}70 mK) and 2nd ({approx}2 K) SQUID stages used with TESs for solar observations. Modification of the Wisconsin ADR design, including TES focal plane and electronics re-positioning, therefore requires a tradeoff between the existing ADR solenoid nulling coil geometry and a low mass passive solenoid shield, while preserving the vibration isolation features of the existing design. We have developed models to accurately compute the magnetic field with and without shielding or nulling coils at critical locations to guide the re-design of the detector subsystem. The models and their application are described.

• OSTI ID: 20800230
• Journal Information: AIP Conference Proceedings, Vol. 823, Issue 1; Conference: Cryogenic engineering conference, Keystone, CO (United States), 29 Aug - 2 Sep 2005; Other Information: DOI: 10.1063/1.2202508; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
ADIABATIC DEMAGNETIZATION
ASTROPHYSICS
CALORIMETERS
COOLING SYSTEMS
COSMIC PHOTONS
DESIGN
GEOMETRY
MAGNETIC FIELDS
MAPPING
REFRIGERATION
REFRIGERATORS
SHIELDING
SHIELDS
SOLAR CORONA
SOLENOIDS
SQUID DEVICES
THERMISTORS
X-RAY DETECTION