Speaker
Brian Ramsey
(NASA/Marshall Space Flight Center)
Description
We are developing a sensitive spectrometer for measuring abundances of light elements fluoresced by ambient radiation. Based on a Silicon Drift Detector (SDD) with custom readout electronics, the instrument offers high energy resolution and large-area coverage, yet with modest power and cooling requirements. The goal of the development program is to build a detector array that can be scaled to any desired area and used in a wide variety of applications from the moon to the extremely harsh environment of the Jupiter system.
The basic systems consist of 16 and 64-channel SDD arrays read out by one and four 16-channel high-speed custom ASICS (application specific integrated circuits) respectively. Once the basic geometry was fixed, we iterated the design to achieve low-energy response, down to the Carbon line at 0.28 keV, using a thin entrance window produced through a double implantation of Boron and Phosphorus ions through the silicon dioxide. We also experimented with the silicon base material resistivity and thickness, to improve radiation hardness in anticipation of operation in challenging environments. In parallel with these efforts we fine tuned the ASIC design for high rate capability and radiation tolerance.
We have investigated the spectroscopic (and rate) performance of our arrays and have recently begun a series of radiation-hardness tests at the Indiana University Cyclotron Facility. To date, we have irradiated two of our early SDD arrays with doses to 0.25 Mrad (as well as relevant Si diodes to 5 Mrad) and our current-iteration ASIC to 12 Mrad. In the near future, we will radiation-test the newly-produced thin-window, radiation-hard, SDD arrays, which we are currently characterizing prior to irradiation.
Full details of our program and our results will be given in this presentation.
Preferred medium (Oral/poster)
Oral
Author
Brian Ramsey
(NASA/Marshall Space Flight Center)
Co-authors
Gianluigi DeGeronimo
(Brookhaven National Laboratory)
Graham Smith
(Brookhaven National Laboratory)
Jessica Gaskin
(NASA/Marshall Space Flight Center)
Shaorui Li
(Brookhaven National Laboratory)
Wei Chen
(Brookhaven National Laboratory)
Zheng Li
(Brookhaven National Laboratory)
