XtRa™

Description

The Mirion XtRa unit is a coaxial germanium detector having a unique thin-window contact on the front surface which extends the useful energy range down to 3 keV. Conventional coaxial detectors have a lithium-diffused contact typically between 0.5 and 1.5 mm thick. This dead layer stops most photons below 40 keV or so rendering the detector virtually worthless at low energies. The XtRa detector, with its exclusive thin entrance window and with a Carbon Composite cryostat window, offers all the advantages of conventional standard coaxial detectors such as high efficiency, good resolution, and moderate cost along with the energy response of the more expensive Reverse Electrode Ge (REGe™) detector.

The response curves below illustrate the efficiency of the XtRa detector compared to a conventional Ge detector. The effective window thickness can be determined experimentally by comparing the intensities of the 22 keV and 88 keV peaks from ¹⁰⁹Cd. With the standard 0.6 mm Carbon Composite window, the XtRa detector is guaranteed to give a 22 to 88 keV intensity ratio of greater than 18:1. Aluminum windows are also available when there is no interest in energies below 30 keV and improved ruggedness is desired. If full advantage of the low energy capability (down to 3 keV) needs to be taken, non-ULB Beryllium windows may be chosen on special request after consulting the factory.