High-Purity Germanium Detectors

HPGe

High-Purity germanium (HPGe) detectors are the recognized gold standard for detection and identification of characteristic gamma rays from nuclear or radiological sources. High- Purity Germanium detectors are mostly used for gamma spectroscopy in nuclear physics, as well as x-ray spectroscopy. SSBI can offer the optimum detector for a wide range of applications. We use both p-type and n-type germanium and we use diffused, implanted, and barrier contacts to achieve this product variety. SSBI Provides a comprehensive suit of HPGe radiation detector solution covering an extensive range of energies and a variety of application

Selecting your Detector: All Our HPGe detectors can be temperature cycled and stored indefinitely at room temperature. Several parameters are useful in the selection of a detector for a particular application.

Energy Range: In general, Coaxial P-type detectors are suitable for energies of 40 keV to 10 MeV. N-type coaxials extend the range down to 4 keV. For lower-energy gammas, planar detectors are recommended for the 3 keV-1 MeV range, since they have better energy resolution and less sensitivity to high energy background than N-type coaxial detectors.

Efficiency: The relative efficiency compares the number of photons detected to the number detected by a 7.62 mm x 7.62 mm (3” x 3”) NaI(Tl) scintillation detector. Efficiency is related to crystal size. Thus, coaxial detectors are frequently “sized” by percent relative efficiency. It is important to select the appropriate size. An overly large detector wastes money and may create high count rate problems. A small detector will be less expensive, but can cost more in time required for an analysis.

Energy Resolution: The usual standard for energy resolution is the full width at half maximum (FWHM) for the full energy peak of the 60Co 1.33 MeV line. Usually, a second value, at one-tenth the maximum (FWTM), is also determined. The ratio of these, FWTM/FWHM, is called peak shape, and is used in computer analysis of complex spectra. For lower-energy regions, the FWHM of the 5.9 keV line of 55Fe or the 122 keV line of 57Co is reported as a metric of detector quality.

Other Factors: The peak-to-Compton ratio is sometimes more important than resolution or efficiency. For planar detectors, the active area, depletion depth, and window thickness need to be considered. We offer three types of preamplifier: resistive feedback, optical reset, and transistor reset. You can also choose among a large range of nitrogen cooled cryostats including dipstick, unitary and portable styles; along with the full electric E-Cooler or the Green Cooler liquid nitrogen generator

Advantages:
  • Our High purity germanium detectors (HPGe) are not just laboratory instruments. HPGe detector systems can go anywhere in the field to search for and identify suspect sources, such as weapons-grade plutonium or radiological dispersal devices.
  • A built-in computer automatically sorts the signals into a gamma-ray spectrum, analyzes it for known nuclides and displays the results.
  • Our system is also now available in packaged into a small-held unit.
  • Our units can operate on external AC or DC power to cool down the detector to operating temperature, while at the same time charging the batteries.
  • The detector systems can then be unplugged from the external power source and operated independently for greater than three hours.
  • It doesn’t take a highly trained analyst to interpret the data in the field.
  • Portable HPGe detector systems are designed for non-technical users.
  • Built-in software can analyze the gamma-ray spectrum reliably and compare the results to a catalog of characteristic peak energies, in order to identify the nuclides in the source.
  • Nuclides found are displayed on the screen and alarms can be set for specific sources.