Rutgers Ultraviolet Detector Lab
Current Projects

Sealed-Tube EBCCD
with superior Cladding Magnet


Electron-Bombarded CCD

Electron Bombarded CCDs offer Detective Quantum Efficiencies that are significantly higher than the commonly used MCP detectors. Sensitivities are 2x higher over wavelengths 120 to 170 nm and 4x higher over near ultraviolet wavelengths (180-250 nm).

New cladding magnet designs developed by the US Army have reduced weight and volume by factors of 3 over conventional magnets. These new magnets produce superior focusing and virtually no external magnetic field. Several far-ultraviolet detectors have flown on the IMAPS (Interstellar Medium Absorption Profile Spectrograph, E. Jenkins, PI) orbital missions. Current research is centered on developing a sealed tube version for near ultraviolet use.

Very Large Focal Plane Detectors for OWL

The Orbiting Wide-angle Light-collectors (OWL) is an envisaged NASA mission to detect ultra high energy cosmic rays. This high-energy-physics mission uses the earth's atmosphere as as the primary detection method. Each cosmic ray creates a brief (fraction of a second) cascade of near-ultraviolet florescence. A pair of 7 meter downward looking telescopes measure the total energy and triangulate from where the cosmic ray came.

The OWL mission will require enormous near-ultraviolet image sensors that are 2 meters by 2 meters squared, a thousand times larger than any previous detector system. To respond to this need, Rutgers is developing detectors based on large TV tubes. The photocathode material replaces the phosphor on the conventional CRT tube. Electrons from this surface are electrostatically de-magnified by a factor of 20 to 30 and slammed into a solid-state device that records the locations of the original photons. Shown is a demountable tube in a cradle in our large vacuum tank, which is being used to test the demagnification properties.

Solid State UV detectors made of AlGaN

Wide-band-gap solid-state detectors made of AlGaN have the potential of becoming the detector of choice for most ultraviolet applications. The wide band gap means these devices do not require cooling, are very insensitive to visible wavelength light, and have very high detective quantum efficiencies (DQE > 80%). Furthermore, solid-state detectors do not require the high voltages that current detectors do, avoiding one inherent reliability risk.

Current AlGaN detectors have non-thermal back grounds associated with material defects. The Naval Research Laboratory in collaboration with Rutgers has made significant strides in reducing these defects and making these detectors suitable for astronomical missions.

Proposed KITE Balloon Mission

KITE - the Kinematical Imaging Trailblazer Experiment is a 0.75 m aperture near-ultraviolet telescope proposed to fly on a conventional balloon, 1-night balloon. It will collect data on the outflows of AGNs (active galactic nuclei) as well demonstrate 2-D velocity maps can be made over a large field of view at a spatial resolution comparable to the Hubble Space Telescope. KITE will serve as a stepping stone towards a 2-3 meter telescope to be flown on a long-duration balloon.

Evaluation of Fabry-Perot Etalons for SALT and GEMINI

The Southern African Large Telescope and the GEMINI telescope provided by the National Optical Astronomical Observatories will be two of the largest ground-based visible-light telescopes. Rutgers is developing, fabricating, and testing a Fabry-Perot instrument for each telescope (T. Williams, PI).

Pictured is a 3.5 meter long optical bench and rail. The test setup has been accurately leveled, vibration isolated, and optically isolated from the rest of the room. Two identical telescopes are used with their eyepieces removed. A pin-hole aperture is placed exactly at the focal length of the primary lens of the first telescope. Light entering this pin hole and exiting the primary lens is (by definition) collimated light. A F-P etalon or an interference filter is attached to an orthogonal slide so that it can be inserted and removed quickly from the beam. After passing through the etalon or filter, the collimated light is refocused by the primary of second telescope onto the entrance slit of the spectrograph (pictured in the far ground).

A single emission line as well as several harmonics of that line can be evaluated simultaneously. The quality of the F-P etalon or of the filter is measured by the width of the spectral lines, the separation of the spectral lines, along with the out-of-band rejection.

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