IDM-200 ®-V
Interchangeable HPGe Detector Module (IDM)
for Systems Integrators
“Free from liquid nitrogen, free from maintenance,
free from integration complexities.”
• 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
• Low-power, reliable Stirling-cycle cooler.
• ORTEC CONNECTIONS family member, compatible with all
ORTEC software applications and developers toolkits, now
Windows 7 compatible.
• Large area 85 mm x 30 mm HPGe crystal: high sensitivity
up to 200% of the surface area of other systems.
HPGe Detector
• Excellent low-energy efficiency
• Uniform detector size
• LN2 free cooling: low power highly reliable Stirling cooler
• Integrated high voltage supply
• High-reliability Stirling-cycle cooler cools rapidly to
operating temperature: NO servicing required.
• Hardened cryostat designed for long operational life: can
be temperature cycled at any time, even from partial
warm up without risk to detector performance.
• Low power consumption and internal battery: continues
counting during power interruptions for ~2.5 hours; longer
with external battery option.
• High performance, digitally stable signal processing:
simpler system integration.
• Low Frequency Rejecter (LFR) algorithm improves
spectrum resolution in noisy environments.
• USB 2.0 data communications: “plug an play”.
• “Hot swap” of IDM-200-V modules while in operational
state: reduced down time.
• Continuous data collection: no dead spots, using list mode.
Integral Dose Rate Monitor
• <0.05 µSv/h to >10000 µSv/h
Digital MCA
• 16k channels
• Pulse-Height Analysis (PHA) mode and streaming list
USB 2.0 Connection
• High speed connection
• Can operate without PC connection if required
External Inputs (2)
• Take count data from other associated devices
• AC/DC power operation
• Internal battery back up: keeps on counting
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
• Bio-Assay
• 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
To facilitate mounting of the IDM200-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.
Germanium Detector
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. See detailed specifications below for more information.
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
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 and 51% relative efficiency HPGe GEM
compared: Absolute efficiency, point source 30 cm.
Typical resolution versus energy.
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
IDM-200-V at the Center of a Wide Range of Applications Solutions.
Radiation Detectors
Internal HPGe Detector Crystal
The HPGe crystal geometry is nominally the same in all IDM-200-V instruments, as following:
Dimensions: 85 mm diameter x 30 mm length nominal. Coaxial construction. P-type high-purity germanium.
Relative Efficiency >50% typical (ANSI/IEEE 325-1996).
Energy Resolution ≤1400 eV @ 122 keV and ≤2.3 keV @ 1332 keV (FWHM Warranted at optimum settings).
Peak Shape 1.9 typical (FWTM/FWHM).
All metal-sealed, long life cryostat, no molecular sieve.
Detector Endcap Thickness
20 thousands (0.5 mm) aluminum.
High reliability, low power Stirling Cooler. Cooler design life >5 years continuous running. Power consumption <30W at
operating temperature.
Cool Down Time
Initial cool down time depends on ambient temperature; typically <15 hours from ambient.
Digital Noise Suppression
"LFR Filter" ORTEC Patent Pending.
Gamma Dose Rate Detector
Two detectors determine the gamma dose rate over a wide range from <0.05 μSv/h to >10000 μSv/h, a dose-rate
range of around six decades. For low dose rates, below ~20 μSv/h, the dose rate is determined from the Ge detector
spectrum. For dose rates above this value, the internal compensated GM tube is used. Instrument switches between
the two automatically.
Dose Rate Uncertainty: < (–50% to +100%).
Digital MCA and Data Processor
System Gain Settings
0.45 to 32.
System Conversion Gain
Software controlled from 512 to 16384 channels.
Digital Filter Shaping-Time
Rise Times: 0.8 µs to 23 µs in steps of 0.2 µs.
Flat Tops: 0.3 to 2.4 in steps of 0.1 µs.
Dead-Time Correction
Extended live-time correction according to Gedcke-Hale method.
Accuracy: Area of reference peak changes <±3% from 0 to 50,000 counts per second.
Low-Frequency Rejecter
When set to ON, removes low-frequency (<3 kHz) input noise from spectrum.
Integral Nonlinearity: <±0.025% over top 99.5% of spectrum, measured with a mixed source (55Fe @ 5.9 keV to 88Y
@ 1836 keV).
Differential Nonlinearity: <±1% (measured with a BNC pulser and ramp generator) over top 99% of range.
Digital Spectrum Stabilizer
Controlled via computer, stabilizes gain and zero errors.
System Temperature Coefficient
Gain: <50 ppm/°C. [Typically <30 ppm/°C.]
Offset: <3 ppm/°C of full scale.
Overload Recovery
At maximum gain, recovers to within 2% of rated output from X1000 overload in 2.5 non-overloaded pulse widths.
(Measured using the InSight Oscilloscope.)
Maximum System Throughput
>100,000 cps, with LFR off, but may be restricted in software >34,000 cps with LFR on. Depends on shaping
parameters and therefore on resolution requirements.
Pulse Pile-Up Rejecter
Automatically set threshold.
Pulse-Pair Resolution
Typically <500 ns.
Automatic Digital Pole-Zero
Computer controlled. Can be set automatically or manually. Remote diagnostics via InSight Oscilloscope mode.
Digital Gated Baseline Restorer
Computer controlled adjustment of the restorer rate (High, Low, and Auto). (Patented.)
Digital lower level discriminator set in channels. Hard cut-off of data in channels below the LLD setting.
Digital upper level discriminator set in channels. Hard cut-off of data in channels above the ULD setting.
Count rate display on PC screen (if enabled).
Physical Specifications
Internal Battery
Rechargeable, nominal 14.4 V lithium-ion battery pack. Charging circuitry and battery management
circuitry internal to the instrument. Battery life 3–5 years. The battery is accessible through a SNAP-open
battery door making it easy to exchange and exhausted battery if the situation demands it.
Operating time on internal
~2.5 hours at 25°C, <4 hour charge time. Operating time may be extended indefinitely by use of external
battery or other power source. ORTEC optional external battery packs are available.
Input Power
10 to 17 V DC from battery or DC power supply (universal mains supply included).
Power Usage
100 W nominal. While charging battery: 72 W nominal. Cold with fully charged battery: nominally 30 W.
Ambient Temperature
(without external enclosure)
Range: –10°C to +50°C.
Relative Humidity: 95%, non-condensing.
Maximum Overall Dimensions
(including Ge detector endcap) 41.3 cm L x 34 cm W x 21.2 cm H (16.26” L x 13.39” W x 8.35” H).
39 lb. (17.7 kg). (Without internal shielding option.)
Maximum Shock Tolerance
20 g. An accelerometer inside the instrument tracks the maximum shock to which the unit has been
subjected. A shock in excess of 20 g will void the warranty.
Ordering Information
IDM-200-V Interchangeable Detector Module. Includes internal backup battery, operating manual, AC/DC power adaptor
charger and USB cable. DOES NOT include MAESTRO MCA software which must be ordered separately.
IDM-200-V with Internal 8 mm tungsten back shield.
AC/DC Power Adapter Charger. (One included with IDM-200-V.)
IP68 USB Cable. (One included with IDM-200-V.)
MAESTRO Multichannel Analyzer (MCA) application software. Includes standalone or first network copy and binary use license.
CONNECTIONS Programmer's Toolkit with ActiveX Controls.
Analysis Results File (UFO) Toolkit.
Specifications subject to change
Tel. (865) 482-4411 • Fax (865) 483-0396 •
801 South Illinois Ave., Oak Ridge, TN 37831-0895 U.S.A.
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