Systèmes de mesure d'objets in situ (ISOCS)
ISOCS Shield Systems
This ISOCS (In Situ Object Counting System) Shield (Figure 1) has been designed as the optimum in convenience and functionality for in situ gamma spectroscopy with a germanium detector.
The system is supplied with both 25 mm and 50 mm lead shielding which gives the user the ability to utilize the sensitivity and low background capabilities of a laboratory grade germanium spectrometer directly on site, regardless of where that site is located.
Unshielded, the detector has a nearly 360° field of view, and can be used for 4π counting of the walls/floors/contents of an entire room. The field of view can be reduced (Figure 2) by adding the shield and collimators to provide fields of view of 30°, 90°, and nearly 180° by simply sliding the appropriate shield components on the mounting rails. In addition, a completely shielded sample chamber can be assembled by combining the components from the two systems.
Its standard wheeled mounting frame makes it easy to move the shield to the assay site, and the individual rear wheel brakes keep it at the desired location.
The mounting frame features both an upper (for 1 meter detector/ground counting) and lower (normal) detector mounting location. The detector can be rotated 180° from down to up, and stopped at any position, not just a few fixed positions, for maximum positioning flexibility. The detector holder even includes a laser pointer to aid in aiming the detector at remote objects.
Whatever the sample and wherever it's located, the ISOCS Shield System has the versatility and flexibility to count it.
- Portable Germanium detector shield system for in situ assays.
- Includes 25 mm and 50 mm thick lead shields.
- Reduces interfering 1000 keV radiation by a factor of 7.5 (25 mm) and 60 (50 mm)
- Modular design for easy handling
- Epoxy paint on all exterior surfaces for ease of cleaning
- Includes 30°, 90°, and 180° collimators (each thickness) plus solid end caps for background measurements
- Includes a rear shield set (requires RDC option on detector)
- Wheeled mounting stand with brakes for ease in moving the shield from one sample to the next
- Large wheels for easy movement: 40 cm (16 in.) at rear, 20 cm (8 in.) in front
- Upper and lower detector mounting positions, with 180° detector rotation at either location
- Easy to assemble and to change detector positions
- Built-in laser aiming device
- Components from 25 mm and 50 mm shields may be combined to build a sample
ISOCS Calibration Software
The ISOCS (In Situ Object Counting System) Calibration Software brings a new level of capabilities to gamma sample assay by eliminating the need for traditional calibration sources during the efficiency calibration process. By combining the detector characterization produced by the MCNP modeling code, mathematical geometry templates, and a few physical sample parameters, the ISOCS Calibration Software gives you the ability to produce accurate qualitative and quantitative gamma assays of most any sample type and size (Figure 1).
In addition to saving money by eliminating the need to purchase, track, and dispose of many calibration sources, ISOCS calibration also saves time in the field. Instead of hours spent in traditional source preparation and long calibration counts, an ISOCS calibration for a new geometry requires only a few seconds of computer calculations. With the ISOCS software you have the flexibility to design your setup, define your geometries, and analyze data in the office; reducing actual time in the field to the system setup and sampling time, no matter how many different geometries you're measuring. And now this capability is available for LaBr3 and NaI scintillators too.
The secret to this capability is twofold:
- The energy/efficiency/spatial response profile of the detector has been characterized by CANBERRA with the well-known MCNP Monte Carlo modeling code.
- Mathematical templates have been created for most of the sample geometries that will be encountered – planar surfaces, rectangular boxes, barrels, pipes, beakers, etc.
To a basic geometry template, add the specifics for a given sample – its size, density, distance from the detector, etc. – and at the click of a button the ISOCS Calibration Software generates a custom efficiency calibration specifically tailored for that detector, sample, and geometry. The remainder of this document will describe how this is done and how the various standard geometry templates are used.
- Eliminates the cost of purchasing, tracking, and disposing of radioactive standards
- No radioactive sources needed for accurate efficiency calibrations
- New: Calibrations valid from
10 to 7000 keV
- New: 3D visualization speeds geometry creation and error identification
- New: Uncertainty Estimator and Assay Planning tool
- New: Advanced Collimator designs include liners and back shielding
- Calibrations valid from detector face out to 500 meters
- Operates with Germanium, NaI and LaBr3 detectors characterized by CANBERRA
- Includes 21 geometry templates for common container shapes and sample distributions
- Calibrations accurate at any angle from detector, not just on center line
- Ideal for In Situ applications, where large and various sample types are often encountered
- Sample size can be point-like,
or up to 500 meters in size
- Includes library of common absorber materials and tools to create new material types
- Custom templates can be provided to meet special application needs
- Multi-Efficiency program allows creation of compound efficiencies for multiple detectors, multiple locations or multiple sources
- Geometry Composer Report summarizing all information defined for a given geometry can be displayed and printed
- Compliant with 2009 NRC Regulatory Guide 1.21
ISOCS In Situ Accessories
Model INSITPOD Lightweight Collapsible Tripod
- Detector height adjustable ~35 - ~100 cm
- Weighs 3.2 kg (7 lb)
- Legs stay in fixed position for quick and easy movement between measurement points
- Small shipping package:
- Legs easily removed and collapse to fit in 60 cm long package
- Attachment plate can stay connected to detector carrier
- Accommodates both MAC and Big MAC
- Accommodates both Slimline or Flanged preamplifiers, with or without RDC
- Will not carry any additional weight (e.g. shield/collimators)
Model 7411 Detector Submarine
- Accommodates single-port MAC
- 6 m (20 ft) umbilical hose (longer available)
- Ballast for fresh or salt water (specify)
- Body dimensions - 178 mm diameter x 591 mm long (7 x 23.25 in.)
- Shipping weight - 20 kg (45 lb)
Model 717 Portable Detector Shield
- For MAC or Big MAC
- 89 mm I.D. x 165 mm long (3.5 x 6.5 in.)
- 25 mm (1.0 in.) thick lead
- Brass lined-steel jacketed
- Shipping weight - 34.5 kg (76 lb)
Model 7413, 7413F Detector Tripod
- For field measurements
- Heavy duty construction
- 7413 accommodates Slimline, MAC or Big MAC
- 7413F accommodates Flanged, MAC or Big MAC
- Detector element elevation (<30 cm to >120 cm)
- Built-in level
- Shipping weight - 9 kg (20 lb)
The ISOCS™ System
For In Situ measurements, the ISOCS™ system has become the most widely accepted measurement tool in the world. The ISOCS system is commonly used to measure contaminated materials and areas, both in place or after removal from the facilities. It is also used for final status measurements to allow release of areas for general use, or general demolition activities.
- Immediate, accurate, nuclide-specific results for field measurement of any object or surface
- Sourceless detector-specific calibrations generated by software as the sample is being counted
- Calibrations generated for any object/surface that can be approximated by plane, cylinder, box, sphere, well/Marinelli or pipe
- Mobile detector positioning device includes 25 mm and 50 mm collimators and backshields, and accommodates any detector orientation
- Complex pipe template allows modeling of complex, multi-layer pipes and drums
- ISOCS Uncertainty Estimator tool (IUE) helps minimize uncertainty and improve results