ORTEC GEM40P4 - User Manual

ORTEC
®
GEM Series Coaxial HPGe Detector
Product Configuration Guide
P-type Coaxial HPGe Detectors for High Performance Gamma
Spectroscopy in the Energy Range of ~40 keV and Up.
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.
ORTEC offers GEM Series HPGe detectors with relative efficiencies
1
from 10% to 150% and beyond. The
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.
Fig. 1. Configuration of GEM Coaxial Germanium
Crystal.
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 Radiation,” ANSI/IEEE Standard 325-1986.

Summary

P-type Coaxial HPGe Detectors

GEM Detector Specifications

Lists energy resolution, photopeak efficiency, peak-to-Compton ratio, peak shape ratio, and 122 keV resolution.

Configuration Guidelines

Explains PopTop vs. Streamline configuration, capsule, cryostat, and vacuum sharing.

ORTEC HPGe Detector Configuration Steps

Detector Model and Cryostat;Dewar Configuration

Steps for configuring detector model components and cryostat/dewar or ICS.

Key Detector Options Overview

Covers ICS, ICS-LB, and SMART-1 detector options for enhanced functionality.

Detector Preamplifier and Window Options

Preamplifier and Harsh Environment Options

Details -PL, -HE, and -HJ options for preamplifier and environmental protection.

Low-Background Carbon Fiber Window Options

Explains -RB, -LB-C, and -XLB-C options for reduced background and low-energy performance.

Streamline Cryostat and Cryostat;Dewar Assemblies

PopTop and Streamline Dimensional Data

GEM Endcap Diameter and Window Specifications

Product Ordering Information

GEM Detector Options and Descriptions

Details detector options like -RB, -HE, -PL, -SMP, -LB-C, -XLB-C, -HJ, and ICS variants.

GEM PopTop Cryostats and Dewars

GEM Streamline Cryostat Configurations

Low-Background Streamline Cryostats

Covers low-background and extra-low-background versions of various cryostat types.

GEM ICS Cryostat Options

Details ICS cryostats for integrated cryocooling systems with external or internal preamps.

GEM Streamline Dewar Selection

ORTEC GEM40P4 Specifications

General

Model	GEM40P4
Relative Efficiency	40%
Detector Type	High-Purity Germanium (HPGe) Detector
Detection Method	Gamma Spectroscopy
Operating Temperature	77 K (Liquid Nitrogen)
Dimensions	Varies with cryostat. Inquire.
Weight	Varies with cryostat. Inquire.