The BeppoSAX Medium Energy GSPC (MECS)

Three of the BeppoSAX GSPC's have 50 micron beryllium windows, thus being sensitive in the range of 1.3-10 keV. The detectors exploit the UV light produced in a high electrical field region to which the electron cloud, resulting from the X-ray photo-absorption, is drifted from the absorption region. The amplitude of the signal, detected by a position sensitive photomultiplier, is proportional to the energy of the absorbed X-ray. The duration of the signal (the burstlenght) is used to discriminate genuine X-rays against events induced by the particle background. The efficiency of the background rejection is greater than 99 % (Giarrusso et al. 1990). The gain of each detector is monitored by two Fe55 radioactive sources (which produce Mn k-alpha with energy of 5.9 keV) at the edge of the instrument.

The flight units of the MECS have been calibrated (together with the flight units of the concentrators) at the Panter X-ray facility in November 1994. The results of the calibrations confirm the expected energy resolution (FWHM) of 8 % at 6 keV and a position resolution at the same energy of 0.7 mm FWHM, corresponding to 0.7 arcmin HPR (Boella et al. 1996), therefore matching well the resolution of the concentrators.

MECS characteristics

More detailed information about this instrument is available from the MECS pages at IFCAI

	Questions should be addressed to: helpdesk@sax.sdc.asi.it

Maintained by L.A. Antonelli , F.Fiore & P.Giommi

Last update: July 23, 1996