Cryogenic energy-dispersive X-ray detectors are being developed
because of their superior energy resolution (10 eV FWHM for keV X-rays)
compared to that achieved in semiconductor energy-dispersive spectrometry
(EDS) systems. So far, their range of application is limited because of
their comparably small size and low count rate. We present data on the
development of superconducting tunnel junction (STJ) detector arrays to
address both of these issues. A single STJ detector has a resolution of
around 10 eV below 1 keV and can be operated at count rates of the order
10,000 counts/sec. We show that the simultaneous operation of several
STJ detectors does not dimish their energy resolution significantly, and
it increases the detector area and the maximum count rate by a factor
given by the total number of independent channels.
Development of an energy-dispersive X-ray spectroscopy analyzer employing superconducting tunnel junction array detectors toward nanometer-scale elemental mapping