Jet-X at MSSL


MART-LIME is being build by IAS in collaboration with IKI. The base-line photon detection system of MART-LIME is a high pressure (5 bar) Xenon-filled MWPC behind a coded mask aperture. The MWPC will be sensitive to energies 5-150 keV with an efficiency higher than 10%. The background rate will be substanstially reduced through a fluorescence gated coincidence mode wherein events for which two coincident pulses are produced are accepted only when a K-alpha or K-beta etc. fluorescence photon (30 keV) is detected within the sensitive volume. The location of photons will be performed through the delay line concept, to an accuracy of the order of 1 mm. Collimation, together with the active veto system of the detector, reduces the background further.

The mask is a URA twin prime with a basic pattern of 71X73 pixels. It will repeated partly with 18 pixels on each side. A collimator, with cells sizes equal to that of a mask pixel, ensures an optimum imaging environment of this coded aperture camera.

Detector typeMulti-Wire Proportional Counter
Detector gasXe
Detector gas pressure at5 atm
Active detector area1744 cm**2
Distance Aperture-Detector2300 mm
Field of View4.6 X 4.9 (FCFOV), ~6 X 6 (PCFOV)
Mask size73 X 71 elements (basic, 105 X 105 total)
Mask element size5.8 X 5.8 mm2
Mask open fraction0.5
Angular Resolution (FWHM), on-axis 8.7 arcmin (40 arcsec SLA for a 5sigma)
Active photon energy range5-150 keV
Photon energy resolution<= 5%
Sensitivity typical~mCrab in one day

Taken from the Coded Aperture Imaging in High Energy Astrophysics pages

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This page is maintained by Dr. Jonathan Mittaz
Last modified 9 June 1997.