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While silicon detectors cannot be thicker than a few millimeters, germanium can have a sensitive layer (depletion region) thickness of centimeters, and therefore can be used as a total absorption detector for gamma rays up to a few MeV. These detectors are also called high-purity germanium detectors (HPGe) or hyperpure germanium detectors.
The AGATA detectors are based on encapsulated and electrically segmented n-type high-purity Ge crystals. They are 36-fold segmented with six-fold azimuthal and six-fold longitudinal segmentation. Each detector is 9 cm long and is circular at the rear side with a diameter of 8 cm, and hexagonal at the front face.
Relative efficiency values are often used for germanium detectors, and compare the efficiency of the detector at 1332 keV to that of a 3 in × 3 in NaI detector (i.e., 1.2×10 −3 cps/Bq at 25 cm). Relative efficiency values greater than one hundred percent can therefore be encountered when working with very large germanium detectors.
A clover detector is a gamma-ray detector that consists of 4 coaxial N-type high purity germanium (Ge) crystals each machined to shape and mounted in a common cryostat to form a structure resembling a four-leaf clover. [1] The clover is the first composite Ge detector.
From 1950 through the early 1970s, this area provided an increasing market for germanium, but then high-purity silicon began replacing germanium in transistors, diodes, and rectifiers. [32] For example, the company that became Fairchild Semiconductor was founded in 1957 with the express purpose of producing silicon transistors.
There are two types of germanium detector, the lithium-drifted germanium or Ge(Li) (pronounced ‘jelly’), and the high-purity germanium or HPGe. The semiconducting element silicon may also be used but germanium is preferred, as its higher atomic number makes it more efficient at stopping and detecting high energy gamma rays.
The experiment used high purity enriched Ge crystal diodes as a beta decay source and particle detector. The detectors from the HdM (Heidelberg-Moscow [2]) and IGEX [2] experiments were reprocessed and used in phase 1. The detector array was suspended in a liquid argon cryostat lined with copper and surrounded by an ultra-pure water tank.
Manufacturer AN/GRC-9: High Frequency (HF) long range radio replacing Signal Corps Radio SCR-694 [131] AN/GRC-46: Radioteletype set originally mounted on M-37 series 3/4-ton truck [132] AN/GRC-103: Lightweight, ultra-high frequency (UHF) tactical radio relay [133] Canadian Marconi Company, Magnavox: AN/GRC-109