The unique detector design combines large area and excellent energy resolution across a wide range of energy, with excellent peak shape, so important in analysis of complex spectra. The result is excellent sensitivity for the detection of small amounts of actinides such as uranium, plutonium, and americium, as well as higher energy fission products and naturally-occurring radioisotopes, in a distributed source such as the human lung.
The large frontal area (>54 cm2
) of ACTINIDE-85 provides high geometrical detection efficiency and superior resolution performance in the lower energy range of actinides such as Pu, Am and U, below around 400 keV, while the crystal depth of 30 mm means good stopping power and excellent relative efficiency at higher energies. The excellent warranted energy resolution at 1.33 MeV, combined with exceptionally good peak shapes, means that the ACTINIDE-85 is the ideal detector solution for analysis of fission products as well.
In lung burden measurements, large diameter detectors allow better coverage of the lung; with ACTINIDE-85, critically important energy resolution is maintained. The special mechanical construction of the cryostat allows two, three, or four ACTINIDE-85 detectors to be placed very close to each other and in contact with the subject. This configuration gives the maximum possible detector efficiency for human lungs. The detector cryostat is made of selected and qualified low background material, based not only on radioactive background characteristics, but also on long-term reliability. The detector endcap is made of an ultra-low background, high-strength carbon fiber composite which provides greater than 85% transmission for photon energy above 15 keV and nearly 100% transmission for photon energy above 20 keV. To further assure and verify low background quality, each detector is placed inside a graded-Z shielding and a background spectrum is taken for 100,000 seconds after assembly. This spectrum is delivered with the detector.
ORTEC ACTINIDE-85 detectors may be ordered in a variety of configurations to meet a variety of requirements for lung burden, body burden, and whole-body counting programs. ORTEC lung burden assessment systems allow independent detector positioning which provide for optimum detector placement and measurement efficiency. In general, positioning mechanisms should be made of carefully screened low-background materials and designed for ease of use and reliability.
Cryostat and Dewar
The standard ACTINIDE-85 is supplied with a 3.5 liter "high fill" dewar. Which provides a typical holding time of 48 hrs.
Mechanical Cooling Options
The ORTEC X-COOLER III or ICS can be employed as an alternative to liquid nitrogen to cool the ACTINIDE-85 detector.
The use of LN2
is costly, time consuming, and (of particular concern for lung burden assessment) is potentially hazardous. In addition, the presence of LN2
can be intimidating to personnel.
The X-COOLER III
is a proven, economical alternative to LN2
for whole-body counting. It can be shown that the savings in LN2
alone will mean that the investment in the X-COOLER III is recovered in a timescale as short as one year.
utilizes a vacuum hardened eliminating the need to fully thermal cycle the detector in the event of a partial warm-up. Investment in the ICS can be recovered in two to three years, yet the long lifetime and excellent reliability of the ICS will make the cooler last nearly as long as the detector itself.
Consult the factory for resolution performance with X-COOLER III or ICS coolers.