GEM P-type HPGe Coaxial Radiation Detector
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P-type Coaxial HPGe Detectors for High Performance Gamma Spectroscopy in the Energy Range of ~40 keV and Up. GEM Series Coaxial HPGe Detector Product Configuration Guide The majority of gamma spectroscopy applications such as those found in counting laboratories involve the energy range ~40 keV upward. ORTEC GEM and Profile Series GEM detectors are designed to cover this energy range. All GEM Series feature: • Efficiencies to 150%, higher on request. • Excellent energy resolution and peak symmetry. • Specified crystal dimensions in Profile models. • SMART bias options. • Harsh Environment (-HE) option. • Low-background carbon fiber endcap options. • PLUS preamplifier option for ultra-high-rate applications. • Huge configuration flexibility: PopTop, Streamline and mechanically cooled options. Fig. 1. Configuration of GEM Coaxial Germanium ORTEC offers GEM Series HPGe detectors with relative efficiencies1 from 10% to 150% and beyond. The Crystal. detectors are manufactured from ORTEC-grown germanium crystals processed in our advanced manufacturing facility in Oak Ridge, TN. The detectors are fabricated from P-type germanium with an outer contact of diffused Li and an inner contact of ion-implanted boron. ORTEC maintains a large stocklist of GEM detectors. Some of these have "super specifications," that is, a warranted energy resolution better than the usual GEM warranted specifications. The Following Specifications are Provided for each GEM Detector • Energy resolution full-width half-maximum (FWHM) at 1.33-MeV and optimum shaping time. • Relative Photopeak efficiency at 1.33 MeV. • Peak-to-Compton ratio at 1.33 MeV. • Peak shape ratio for the full-width tenth-maximum to the full-width half-maximum at 1.33 MeV. • Energy resolution at 122 keV at optimum shaping time. Configuration Guidelines PopTop or Streamline (non-PopTop) Configuration The essence of a PopTop detector system is that the HPGe detector element cryostat, preamplifier, and high voltage filter are housed in a detector “capsule” which is then attached to an appropriate cryostat (Figure 2.) In Streamline systems, the detector capsule is NOT demountable. Detector capsule and cryostat share the same vacuum. In configuration terms, this requires a cryostat or cryostat/dewar selection with the cryostat having a matching diameter to the capsule endcap or an integrated cryocooling system (ICS). A cryostat or ICS must always be ordered with a Streamline capsule, because they are integral. The actual PopTop capsule has its own vacuum. It can be mounted on any of the available cryostats, cryostat/dewar combinations, or the X-COOLER III or ICS-P4 mechanical cooling systems. Certain cryostat configurations are available only as PopTop and others are available only as Streamline. 1 By convention, HPGe detectors are characterized by “relative efficiency”. Relative efficiency is defined as the efficiency of a point Co-60 source at 25 cm from the face of a standard 3-inch x 3-inch right circular cylinder NaI(Tl) detector. “IEEE Test Procedures for Germanium Detectors for Ionizing Radiat

GEM Series Coaxial HPGe Detector Product Configuration Guide Steps to Configure Your ORTEC HPGe Detector 1) Configure the Detector Model • Capsule type (PopTop or Streamline) • Ge Crystal efficiency and specifications • Endcap and window • Mount • Preamplifier • High Voltage Filter • Cable Package • Integrated Cryocooling System (ICS) Options are available for the detector model that can change specific materials used in the construction of the detector endcap, cup, and mount. Preamplifier options are also available. 2) Configure the Cryostat/Dewar or ICS Model Fig. 2. Diagram of PopTop...

Ultra-High Count-Rate Preamplifier Option (-PL) The Ultra-High Count-Rate Preamplifier (transistor-reset preamplifier), can handle input count rates up to 1,000,000 counts/s at 1 MeV, offers the added benefit of having no feedback resistor. Harsh Environment Option (-HE) The Harsh Environment option is a rugged carbon fiber endcap with a sealed electronics housing featuring a replaceable desiccant pack which ensures that the electronics stay 100% dry and indicates when it needs to be replaced. GEM series detectors in PopTop capsules of 76 mm diameter or larger can be supplied with this...

GEM Series Coaxial HPGe Detector Product Configuration Guide PopTop Detector Capsule Preamplifier default is Resistive Feedback -PL changes to Transistor Reset -SMP changes to SMART-1 with HV Preamplifier Outside Vacuum PopTop Cold Finger Coupling Window default is Al -RB and -HE change to Carbon Fiber High Voltage Filter Electronic Shroud -HE changes to a sealed chamber with additional .25” dia and .4” length, and adds a replaceable desiccant. Mount default is Al -RB changes to Cu Endcap default is Al -RB and -HE change to Carbon Fiber Streamline Detector Capsule Electronic Shroud...

GEM Series Coaxial HPGe Detector Product Configuration Guide Streamline Detector Capsule for Integrated Cryocooling System with Internal Preamplifier (ICS) Preamplifier default is Resistive Feedback -PL changes to Transistor Reset Preamplifier Outside Vacuum High Voltage Filter Cup default is Al -ICS-LB changes to low-background Al Window default is Al -ICS-LB changes to High Purity Al ICS-LLxxx xxx = specified length See Chart Mount default is Al -ICS-LB change to Cu Endcap default is Al -ICS-LB changes to High Purity Al Streamline Detector Capsule for Integrated Cryocooling System with...

GEM Series Coaxial HPGe Detector Product Configuration Guide Streamline Cryostat and Cryostat/Dewar Assemblies Streamline systems (detector capsule and cryostat) share the same vacuum, requiring a cryostat or cryostat/dewar selection with the cryostat having a matching diameter to the capsule endcap. Diameter must match Endcap Diameter -70, -76, -83, -95 or -108 Standard Cryostat uses Molecular Sieve Pumping Agent. -LB changes Pumping Agent to charcoal. -XLB adds Internal Pb Shield Diameter must match Endcap Diameter -70, -76, -83, -95 or -108 Standard Cryostat uses Molecular Sieve Pumping...