EBEX Stratospheric Balloon-borne CMB Polarimeter

The inflationary big bang model is the leading theory describing the origin of the universe. A tiny fraction
(10-35) of a second after the big bang the
universe undergoes a period of faster than light-speed expansion that stretches minuscule quantum fluctuations out to
cosmic scales. These fluctuations are the seeds that later lead to structure formation in the universe. (Right: simplified representation of inflation (figure from NASA outreach))

A direct prediction of these models is the production of inflationary gravity waves that imprint a polarization signature on the Cosmic Microwave Background (CMB).

In collaboration with a team of international researchers, we're developing a mm-wavelength polarization sensitive 1.5m telescope called EBEX that will be flown by NASA to about 100,000 feet aboard a stratospheric balloon. 
(The Maxipol balloon, a predecessor to EBEX is shown left. The EBEX gondola is shown at right, shortly after delivery to the Columbia University high bay at Nevis.)

Detection of polarization from inflationary gravity waves is one of the main science goals of the E and B experiment (EBEX). EBEX will measure the polarization of the CMB to provide a glimpse of the universe at its very earliest stages. 

The focal plane of EBEX will be instrumented with 1400 Transition Edge Sensor (TES) detectors, read out with McGill's Digital Frequency Domain Multiplexer electronics. Polarization sensitivity is achieved with a half wave plate and polarizing grid. It will flown first on a one day test flight above Texas, before traveling to Antarctica for a ~30 day long duration flight around the South Pole.

At McGill, our team consists of Prof. Matt Dobbs, postdoc Peter Hyland, and graduate students Francois Aubin and Kevin MacDermid.

(Left: members of the EBEX collaboration in front of the gondola.)

Selected Publications:

  • P. Oxley et al., "The EBEX Experiment",  Proc. SPIE Int. Soc. Opt. Eng. 5543 (2004) 320-331 [arXiv:astro-ph/0501111v1].
  • M. Dobbs, E. Bissonnette, H. Spieler, "Digital Frequency Domain Multiplexer for mm-Wavelength Telescopes", IEEE Transactions in Nuclear Science 55, (2008) 21-26.