Dr. Gary Varner Profile

Dr. Gary Varner

Sr. Electrical Engineer at Univ of Hawai'i at Manoa

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Publications (6)

Proceedings Article | 18 July 2016 Paper

Development of a flight qualified 100 x 100 mm MCP UV detector using advanced cross strip anodes and associated ASIC electronics

John Vallerga, Jason McPhate, Anton Tremsin, Oswald Siegmund, Rick Raffanti, Harley Cumming, Andrej Seljak, Vihtori Virta, Gary Varner

Proceedings Volume 9905, 99053F (2016) https://doi.org/10.1117/12.2233697

KEYWORDS: Sensors, Microchannel plates, Amplifiers, Electronics, Field programmable gate arrays, Analog electronics, Spatial resolution, Connectors, Ultraviolet radiation, Detector development

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Photon counting microchannel plate (MCP) imagers have been the detector of choice for most UV astronomical missions over the last three decades (e.g. EUVE, FUSE, COS on Hubble etc.) and been mentioned for instruments on future large telescopes in space such as LUVOIR¹⁴. Using cross strip anodes, improvements in the MCP laboratory readout technology have resulted in better spatial resolution (x10), temporal resolution (x 1000) and output event rate (x100), all the while operating at lower gain (x10) resulting in lower high voltage requirements and longer MCP lifetimes.

A crossed strip anode MCP readout starts with a set of orthogonal conducting strips (e.g. 80 x 80), typically spaced at a 635 micron pitch onto which charge clouds from MCP amplified events land. Each strip has its own charge sensitive amplifier that is sampled continuously by a dedicated analog to digital converter (ADC). All of the ADC digital output lines are fed into a field programmable gate array (FGPA) which can detect charge events landing on the strips, measure the peak amplitudes of those charge events and calculate their spatial centroid along with their time of arrival (X,Y,T) and pass this information to a downstream computer.

Laboratory versions of these electronics have demonstrated < 20 microns FWHM spatial resolution, count rates on the order of 2 MHz, and temporal resolution of ~ 1ns. In 2012 our group at U.C. Berkeley, along with our partners at the U. Hawaii, received a NASA Strategic Astrophysics Technology (SAT) grant to raise the TRL of a cross strip detector from 4 to 6 by replacing most of the 19" rack mounted, high powered electronics with application specific integrated circuits (ASICs) which will lower the power, mass, and volume requirements of the detector electronics. We were also tasked to design and fabricate a "standard" 50mm square active area MCP detector incorporating these electronics that can be environmentally qualified for flight (temperature, vacuum, vibration).

ASICs designed for this program have been successfully fabricated and are undergoing extensive testing. We will present the latest progress on these ASIC designs and their performance. We will also show our preliminary work on scaling these designs (detector and electronics) to a flight qualified 100 x 100 mm cross strip detector, which has recently been funded through a follow on SAT grant.

Proceedings Article | 25 July 2014 Paper

Cross strip anode readouts for large format, photon counting microchannel plate detectors: developing flight qualified prototypes of the detector and electronics

John Vallerga, Rick Raffanti, Michael Cooney, Harley Cumming, Gary Varner, Andrej Seljak

Proceedings Volume 9144, 91443J (2014) https://doi.org/10.1117/12.2058412

KEYWORDS: Microchannel plates, Sensors, Amplifiers, Electronics, Spatial resolution, Field programmable gate arrays, Analog electronics, Photon counting, Ultraviolet radiation, Detector development

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Proceedings Article | 29 July 2010 Paper

Large-format high-spatial resolution cross-strip readout MCP detectors for UV astronomy

John Vallerga, Rick Raffanti, Anton Tremsin, Oswald Siegmund, Jason McPhate, Gary Varner

Proceedings Volume 7732, 773203 (2010) https://doi.org/10.1117/12.857820

KEYWORDS: Sensors, Microchannel plates, Field programmable gate arrays, Electronics, Analog electronics, Spatial resolution, Amplifiers, Finite impulse response filters, Clocks, Ultraviolet radiation

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Proceedings Article | 3 March 2003 Paper

Monolithic multichannel GSa/s transient waveform recorder for measuring radio emissions from high-energy particle cascades

Gary Varner, Peter Gorham, Jing Cao

Proceedings Volume 4858, (2003) https://doi.org/10.1117/12.458018

KEYWORDS: Analog electronics, Device simulation, Antennas, Atmospheric particles, Sensors, Interference (communication), Stanford Linear Collider, Capacitance, Polarization, Logic

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Proceedings Article | 3 March 2003 Paper

Antarctic impulsive transient antenna (ANITA) instrumentation

S. Barwick, James Beatty, David Besson, John Clem, Stephane Coutu, Michael DuVernois, Paul Evenson, Peter Gorham, Francis Halzen, David Kieda, John Learned, Kurt Liewer, Shigenobu Matsuno, Charles Naudet, David Saltzberg, David Seckel, Gary Varner

Proceedings Volume 4858, (2003) https://doi.org/10.1117/12.458042

KEYWORDS: Antennas, Polarization, Physics, Logic, Particles, Interference (communication), Field programmable gate arrays, Astronomy, Sensors, Amplifiers

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Showing 5 of 6 publications

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