Instrument Description

SIXA is a multi-element X-ray photon counting spectrometer. It is one of the focal plane instruments for SODART Telescope 2. Its high sensitivity, broad energy range, and good temporal and spectral resolution make it well-suited for obtaining time-resolved spectra and studying spectral lines.

SIXA consists of 19 discrete hexagonally arranged circular elements with a centerline distance of 12 mm (Figure 57). Each element is a 3 mm thick wafer of lithium-drifted silicon (Si(Li)). A radiative cooler is used to bring the detector to the proper operating temperature (120-130 K), and aluminium coated polyimide windows are used to filter out IR/visible/UV light. A number of different observing modes allow the accumulation of individual photon event lists, integrated energy spectra or light curves, or time interval histograms. Table 8 gives a summary of the properties of SIXA. The total response of the SIXA/SODART system is demonstrated in Figure 58.

 

Table 8: SIXA Detector Parameters

Diameter of active area	6 cm
Field of view	25$^{\prime}$
Number of pixels	19
Total/active pixel diameter	12/9.25 mm (5.16$^{\prime}$/3.97$^{\prime}$)
Number of energy channels	1024
Width of each channel	20 eV
Effective energy range	0.5-20 keV
Energy resolution (FWHM)	200 eV at 6 keV
Time resolution	30.5 $\mu$sec (TIM mode: 12.21 $\mu$sec)
Spatial Resolution	4$^{\prime}$
Non-X-Ray Background	$\sim1.3\times10^{-2}$ c s-1 pixel-1
X-ray Background (on-axis)	$\sim1.7\times10^{-2}$ c s-1 pixel-1
Depletion depth	3 mm
Operating temperature	120-130 K