Superconductivity and the Cosmic Microwave Background

1
Superconductivity and the Cosmic Microwave
Background

• Karl Franz Flasch Hendrickson
• Truman State University
• Kirksville, Missouri
• REU 2003

2
OrThe Taming of the SQUID
3
The CMB A Brief Review
4
The Detection Method

• Two issues
• Stray Magnetic Fields
• Readout

5
Those Mangy Magnetic Fields
Problem Stray Magnetic Fields will produce too
much current for the Superconductor
Solution?

• Sources
• Earths Magnetic Field
• Detector wiring
• Refrigeration System

6
Magnetic Shielding Test
7
Whats in the Dewar?
8
Magnetic Shielding Test Results
Strength of field shielded 2.3 mT Earths
B-Field 0.04 mT
9
SQUIDs

• Superconducting Quantum Interference Devices

• What is it?
• A ring of superconducting metal
• Total flux through loop stays constant

• Advantages
• Sensitive to magnetic fields producing a change
  in one flux quanta F0
• Lowest noise Ammeter possible

10
SQUIDs and Bolometers
Rs Shunt Resistor Rb Bolometer C Capacitor
Filter RsltltRb
Vout CsIext Cs is SQUID specific
11
SQUIDs and Bolometers Results
Rs6.20.610 m ? O Rb24210 m ? O
After much struggle
12
SQUIDs and Bolometers The Next Step

• Bias the bolometer with AC Voltage
• Use a lock-in amplifier to read
• Read multiple Bolometers with a single SQUID
  readout

13
Acknowledgements

• Dr. Peter Timbie, Advisor
• Dr. Shafinaz Ali and Dr. Jean-Marc Duval,
  Post-Docs
• Peter, Seth and Ben
• The Rest of the Observational Cosmology Group
• Dr. Charlie Silver, former ObCos Post-Doc

14
References

• UW Observational Cosmology http//cmb.physics.wis
  c.edu/
• Wayne Hus CMB Page http//background.chicago.edu
  /whu/
• UW X-Ray Labs TES page http//wisp11.physics.wis
  c.edu/xray/
• Rose-Innes, A.C. and Rhoderick, E.H. Introduction
  to Superconductivity. 2nd Ed. PergamonOxford,
  1978.
• Star Cryoelectronics Mr. SQUID Users Guide