Detectors germanium

Fig. 9. Spectral sensitivity of detectors where the detector temperatures in K are in parentheses, and the dashed line represents the theoretical limit at 300 K for a 180° field of view, (a) Detectors from near uv to short wavelength infrared (b) lead salt family of detectors and platinum siUcide (c) detectors used for detection in the mid- and long wavelength infrared. The Hg CdTe, InSb, and PbSnTe operate intrinsically, the doped siUcon is photoconductive, and the GaAs/AlGaAs is a stmctured supedattice and (d) extrinsic germanium detectors showing the six most popular dopants.

CCL) can be easily incorporated into this configuration. It gives us the additional spectral range of 0.77 to 0.86 eV. The typical pulsewidth of the mode-locked CCL is about 20 ps, but can be improved to 200 fs by using a saturable absorber. A germanium detector has been used for the detection of the CCL probe beam. 

To remove this interference, an associated technique such as x-ray radiography could be used to iook for copper articles. Also high-maintenance, high-resolution germanium detectors might allow... 

Graham SG, Kirkman SJ. 1983. Identification of 241Am in the axillary lymph nodes with an intrinsic germanium detector. Health Phys 44 343-352. 

Krosshaven et al. [64] used scintillation spectrometry employing germanium detectors to measure 137 caesium and strontium in coastal seawaters. 

Chassery et al. [97] studied the 87Sr/86Br composition in marine sediments, observing excellent agreement between results obtained by ICP-MS and thermal ionisation mass spectrometry. Low level a-spectrometry with lithium drifted germanium detectors has been used to determine 90strontium in seawater [59]. 

From the exit slit, the beam is directed to either of two detectors by the movable mirror behind the exit slit. Typical detectors are InSb, a photovoltaic indium antimonide detector operated at 77 K, and He Ge, a photo-conductive mercury-doped germanium detector maintained at 15 K by a closed-cycle helium refrigerator... 

Radionuclidic analyses are performed with either a lithium-drifted germanium or intrinsic germanium detector. The assay for Sr-82 is based upon its 777 keV photon of 13.6% abundance. Strontium-85, which is often present in amounts comparable to that of Sr-82, is assayed by its 514 keV photopeak, which must be resolved from prominent 511 keV annihilation radiation by a curve stripping procedure (12). 

Lithium-Drifted Germanium Detectors. Two kinds of planar Ge(Li) diodes were fabricated in our Laboratory for the spectrometer (I). The chief consideration was maximum cross section with a resolution of less than 3 k.e.v. at 60Co FWHM (full width half maximum). The available single-crystal germanium material dictated the shape of the detector. The first detector was fabricated from a 15-cm. long Sylvania ingot with a trapezoidal cross section its finished dimensions were 6 cm. X 3 cm. X 1 cm. Our second detector was fabricated from circular Hoboken stock (NPC Metal and Chemical Co., Los Angeles) its finished dimensions were 2.8 cm. diameter X 1.2 cm. thick. 

Germanium detectors provide the highest resolution for y-rays possible with reasonable efficiency, so our system is based on an array of such detectors. For cascade y rays (in prompt coincidence) an improvement in the effective resolution is possible by using double- and higher-coincidence spectra rather than singles. For this reason, and to obtain good statistics, as many detectors as close to the target as is reasonably possible is desirable (see below). 

Fig. 4. Portion of the 165Ho(a,3ny)166Tm spectrum observed with the on-line bent crystal spectrometer and with a good resolution germanium detector in the inset (the corresponding region is represented with open circles). Transitions are identified by their approximate energy in keV.

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