Project Title:

High-Resolution, Avalanche-Diode X-Ray Spectrometer for Planetary Exploration

05.05-1167
High-Resolution, Avalanche-Diode X-Ray
	Spectrometer for Planetary Exploration
Radiation Monitoring Devices, Inc.
44 Hunt Street
Watertown, MA 02172
Gerald Entine  (617-926-1167)
JPL -- NAS7-1018

Abstract:

	 The selection of the best samples to bring back to earth from the Mars planetary
exploration mission will require the development of analytical techniques compatible
with the unusual mission environment. X-ray fluorescence analysis techniques are
particularly attractive, and the new, avalanche-diode, x-ray spectrometer could help
provide the performance needed to make this technique applicable.
	The Phase I project demonstrated the feasibility of making high resolution, avalanche-
diode detectors capable of the sensitivity and resolution needed for the Mars Lander
mission. Studies conducted to determine the underlying phenomena presently limiting
the spectral resolution of these devices under reduced temperatures clearly identified
the two primary limiting factors. Both of these factors were successfully addressed
during this project.
	Phase I also resulted in the first reported X-ray fluorescence spectrum taken with
an avalanche photodiode of an element as light as sulfur. Furthermore, the noise
level of these diodes was lower than any previously reported for a non-cryogen-cooled
semiconductor detector.

Potential Commercial Application:

Potential Commercial Application: The applications are in X-ray fluorescence analysis,
an important analytical technique with many industrial, military and research applications.
This technology will reduce the cost significantly and also make portable field units
much more practical.