Saturday, April 21 , 2018, 2:45 pm | Fair 70º

 
 
 
 

UCSB Professor Develops Cutting-Edge Detector Technology for Astronomical Observations

Semiconductors have had a nice run, but for certain applications, such as astrophysics, they are being edged out by superconductors. Ben Mazin, assistant professor of physics at UC Santa Barbara, has developed a superconducting detector array that measures the energy of individual photons. The design and construction of an instrument based on these arrays, as well as an analysis of its commissioning data, appear in the Publications of the Astronomical Society of the Pacific.

Ben Mazin
Ben Mazin

"What we have made is essentially a hyperspectral video camera with no intrinsic noise," Mazin said. "On a pixel-per-pixel basis, it's a quantum leap from semiconductor detectors; it's as big a leap going from film to semiconductors as it is going from semiconductors to these superconductors. This allows all kinds of really interesting instruments based on this technology."

Mazin's ARray Camera for Optical to Near-infrared (IR) Spectrophotometry (ARCONS) is the first ground-based instrument optical through near-IR using Microwave Kinetic Inductance Detectors (MKIDs). An MKID is a type of superconducting photon detector; microwave refers to the readout frequency rather than the frequency at which the detectors operate.

MKIDs were first developed a decade ago by Mazin, his Ph.D. adviser Jonas Zmuidzinas, professor of physics at the California Institute of Technology, and Dr. Henry LeDuc at NASA's Jet Propulsion Laboratory. MKIDs are used in astronomy for taking measurements across the electromagnetic spectrum. In his lab at UCSB, Mazin has adapted these detectors for the ultraviolet, optical and near-IR parts of the spectrum.

Superconductivity is a quantum phenomenon that occurs as certain materials are cooled to near absolute zero, thereby eliminating all electrical resistance and magnetic fields. MKIDs, which operate at cryogenic temperatures (typically 0.1 Kelvin), allow astronomers to determine the energy and arrival time of individual photons.

"Forty years ago we were doing optical astronomy with photographic plates, which use light to change a chemical emulsion," Mazin said. "When we switched from photographic plates to the charge couple devices (CCDs) contained in today's electronics, per-pixel performance of the detectors went up by a factor of 20.

"In the last decade, CCDs and other semiconductor-based detectors for the optical and near-IR have started to hit fundamental limits in their per-pixel performance. They've gotten about as good as they can get in a given pixel. The way they continue to improve is by making huge pixel mosaics, which is appropriate for many but not all applications."

For observations of rare objects like optical pulsars and high redshift galaxies, ARCONS' small field of view (20 inches by 20 inches) is not a drawback. In fact, it exponentially improves observing efficiency as compared to conventional filter-based multicolor observations. Another advantage of MKIDs is time resolution, which shows the arrival of each and every photon. This allows astronomers to see rapidly changing events, a great advantage for many observations.

MKIDs have inherent frequency domain multiplexing capabilities, which enable thousands of devices to be read out over a single microwave feed line. The size of the arrays is limited by the microwave readout, which uses very similar technology to a cellphone base station. This means the number of MKIDs that can be read out for a given price is increasing according to Moore's Law — overall processing power for computers doubles every two years — which should enable megapixel arrays within a decade.

Mazin and his team lens-coupled a 2024-pixel array to the Palomar 200-inch and the Lick 120-inch telescopes in Southern California and Northern California, respectively. ARCONS was on these telescopes for 24 observing nights, during which data was collected on optical pulsars, compact binaries, high redshift galaxies and planetary transits.

"ARCONS is very sensitive but it's been coupled with 5-meter telescopes," Mazin said. "The 8- to 10-meter telescopes, such as Keck, are at better sites with four times the collecting area. We hope to deploy MKID instruments in the next several years at Keck and other telescopes to make fascinating new observations, including using MKIDs coupled to a coronagraph to directly discover and take spectra of planets around nearby stars."

  • Ask
  • Vote
  • Investigate
  • Answer

Noozhawk Asks: What’s Your Question?

Welcome to Noozhawk Asks, a new feature in which you ask the questions, you help decide what Noozhawk investigates, and you work with us to find the answers.

Here’s how it works: You share your questions with us in the nearby box. In some cases, we may work with you to find the answers. In others, we may ask you to vote on your top choices to help us narrow the scope. And we’ll be regularly asking you for your feedback on a specific issue or topic.

We also expect to work together with the reader who asked the winning questions to find the answer together. Noozhawk’s objective is to come at questions from a place of curiosity and openness, and we believe a transparent collaboration is the key to achieve it.

The results of our investigation will be published here in this Noozhawk Asks section. Once or twice a month, we plan to do a review of what was asked and answered.

Thanks for asking!

Click Here to Get Started >

Support Noozhawk Today

You are an important ally in our mission to deliver clear, objective, high-quality professional news reporting for Santa Barbara, Goleta and the rest of Santa Barbara County. Join the Hawks Club today to help keep Noozhawk soaring.

We offer four membership levels: $5 a month, $10 a month, $25 a month or $1 a week. Payments can be made through PayPal below, or click here for information on recurring credit-card payments.

Thank you for your vital support.


Maestro, Mastercard, Visa, American Express, Discover, Debit

Reader Comments

Noozhawk is no longer accepting reader comments on our articles. Click here for the announcement. Readers are instead invited to submit letters to the editor by emailing them to [email protected]. Please provide your full name and community, as well as contact information for verification purposes only.

Daily Noozhawk

Subscribe to Noozhawk's A.M. Report, our free e-Bulletin sent out every day at 4:15 a.m. with Noozhawk's top stories, hand-picked by the editors.

Sign Up Now >