Joel N Ullom

Learn More
SCUBA-2 is an innovative 10000 pixel bolometer camera operating at submillimetre wavelengths on the James Clerk Maxwell Telescope (JCMT). The camera has the capability to carry out wide-field surveys to unprecedented depths, addressing key questions relating to the origins of galaxies, stars and planets. With two imaging arrays working simultaneously in the(More)
Multiplexed superconducting quantum interference device ͑SQUID͒ readout systems are critical for measuring large arrays of superconducting transition-edge sensors ͑TES͒. We demonstrate a code-division SQUID multiplexing ͑CDM͒ architecture that is modulated by Walsh codes. Measurements and simulations of a prototype multiplexer show that this modulation(More)
We present the multiplexed readout of two gamma-ray microcalorimeters made from transition-edge sensors. We use a frequency-domain multiplexing scheme in which each sensor is biased at an identifying frequency. We show that the energy resolution of the sensors is unaffected by multiplexing, and that crosstalk between the sensors is negligible. Our results(More)
We describe a laser-driven x-ray plasma source designed for ultrafast x-ray absorption spectroscopy. The source is comprised of a 1 kHz, 20 W, femtosecond pulsed infrared laser and a water target. We present the x-ray spectra as a function of laser energy and pulse duration. Additionally, we investigate the plasma temperature and photon flux as we vary the(More)
The Multiplexed SQUID/TES Array at Ninety Gigahertz (MUSTANG) is a bolometric continuum imaging camera designed to operate at the Gregorian focus of the 100m Green Bank Telescope (GBT) in Pocahontas county, West Virginia. The combination of the GBT's large collecting area and the 8x8 array of transition edge sensors at the heart of MUSTANG allows for deep(More)
  • 1