- Convenient-to-mount, all-in-one integrated HPGe detector, cooler, cryostat, and signal processing electronics; requires only AC/DC power and a USB connection.
- Operates in any orientation.
- Standardized large area HPGe crystal dimensions ensures uniform performance unit-to-unit.
- Maintenance free.
- Hardened cryostat eliminates “partial warm up” problem.
- Mains power and DC operation.
- Remains operational from internal battery for ~2.5 hours following power failure. Longer battery life options available (external).
- Low-power, reliable Stirling-cycle cooler.
- ORTEC CONNECTIONS family member, compatible with ORTEC software applications and developers toolkits.
The IDM-200-V Interchangeable Detector Module from ORTEC is a high performance gamma-ray spectrometry “building block” for use in multiple applications. It is a completely self-contained package, comprising a single, large-area, mechanically cooled high-purity germanium (HPGe) detector of standardized crystal dimensions and all necessary spectrometry electronics in a RUGGED, low-power configuration.
The IDM-200-V includes everything needed for the high resolution spectrometry task, producing either a resultant spectrum in memory or delivering a digitized pulse stream in list mode format to an attached PC for further analysis.
Compatible with ORTEC software applications such as MAESTRO, GammaVision and ISO-Plus, the IDM-200-V may also be controlled from third party developed software via the use of optional ORTEC software tool kits.
These attributes make the IDM-200-V a perfect solution for a wide range of measurements and applications where spectroscopic performance, reliability and convenience are of paramount importance. It is ideally suited for OEM applications as a component within a larger measuring system in applications such as:
• Waste Assay
• Homeland Security
• Continuous Air Particulate Monitoring
• Industrial Process Monitoring
• Aerial Survey
IDM-200-V instruments are designed for long, reliable service, and are interchangeable, one with another. The IDM-200-V is light enough to be installed by one person. The ORTEC CONNECTIONS Programmer’s Toolkits are available to assist the systems integrator.
The IDM-200-V has been designed specifically for use in integrated measurement systems which require HPGe spectrometry. All the components are derived from ORTEC technology, proven in the field by hundreds of Detective portable identifiers.
The IDM-200-V is a compact detection instrument subsystem. During operation, approximately 30 watts of power (only) are required to operate the entire system either on DC or AC through a converter (supplied). Minimal waste heat greatly simplifies mounting considerations. Low power consumption means systems configured using the IDM-200-V do not need high levels of cabinet air conditioning.
The HPGe detector is optionally shielded at the back of the cryostat with 8 mm of tungsten. Custom collimators are available to restrict the forward field of view. A steel collimator, set flush with the detector endcap, is supplied with the standard instrument.
To facilitate mounting of the IDM-200-V, six blind threaded holes are provided in the casing.
Digital Signal Processing Electronics
The digital signal processing (DSP) electronics subsystem used in the IDM-200-V is derived from the ORTEC DSPEC and Detective family systems. The low power design has extremely high stability with both count-rate and temperature variation, important in many of the applications which may be encountered by systems integrators.
Operation as part of an integrated measurement system presents new challenges compared to laboratory operation. A common non-laboratory complication that can lead to reduced system performance is mechanical vibration or acoustic noise. The energy resolution of HPGe detectors can be degraded by mechanical vibration or microphonic noise. A special “low frequency reject” feature greatly reduces the possibility of this occurring in noisy non-laboratory environments.
The ~50% relative efficiency HPGe detector in the IDM-200-V is of an “over-square” diameter-to-length profile. The large diameter enhances low energy efficiency. The figures below show the point source absolute efficiency curves of an IDM-200-V in comparison with a more conventionally profiled detector of almost the same relative efficiency (51%). The IDM-200-V shows much higher efficiencies at low to medium energies, where container or matrix absorption effects are possible to be problematic to measurements.
Radiation Entrance Window: Excellent transmission is achievable at incident gamma-ray energies of 60 keV and above.
For more than 20 years, ORTEC has been a leader in the development and deployment of mechanically cooled HPGe detectors.
The IDM-200-V cryostat design evolved from the Detective Hand-Held Identifier, itself a non-traditional design, which does not use molecular sieve as a cryo-pump, but does use all-metal seals and extremely clean construction methods. The all-metal seal construction results in a robust, long-life cryostat which can be temperature cycled, either completely or partially, indefinitely. The cooler can be turned off then on again at any time, with no risk, greatly aiding service operations.
IDM-200-V Data Collection Modes
Data are usually collected by the IDM-200-V in Pulse Height Analysis (PHA) mode and transferred to a PC for further analysis. There is a small dead time when the data are being transferred during which new data are not collected. If absolutely no loss of data is an essential need, then, a solution exists in the form of List mode acquisition. In the List mode of operation, data are stored directly to computer memory, event by event, with a time stamp (200 nanoseconds). These data can then be reconstructed into separate spectra by time, energy, or position. This feature of the IDM-200-V greatly enhances the detection sensitivity of the system in many applications.
High speed plug-and-play USB 2.0 communications makes module control and data collection fast and easy.
The replacement of an IDM-200-V is particularly fast and straightforward. Only two connections are required, line power and USB.