Examination of Firearms Review: 2007 to 2010 - Interpol

detection systems for plague may now be needed in non-endemic regions
and the existing rapid tests for the diagnosis of plague have been reviewed. 35
4.1.4 Radiological
The techniques for the detection of alpha, beta, gamma and neutron radiation
are well established and current research in the field is mainly focussed in
increasing the sensitivity of these methods. The current state of commercial
instruments has recently been reviewed for different categories of detection
equipment including personal radiation detectors, radioisotope identifiers,
man-portable detection equipment, and radiation portal monitors. In addition,
emerging technologies are being examined, such as spectroscopic detectors
and advanced spectroscopic portal monitors. 36 . The principle of operation and
properties of several types of detectors have also been reviewed, briefly
detailing the functioning of ionization and wire chambers, semiconductor
detectors, and scintillation detectors. 37
4.2 Optically-Stimulated Luminescence
Optically-Stimulated Luminescence (OSL) is a detection technique that allows
the detection of items that have been in close proximity with a radioactive
source. This technique has great potential for counter-terrorism, in helping to
determine locations where a source or a radioactive device may have been
stored.
Ionizing radiation, from a radioactive source, can create charges within
mineral crystals that may be present around it (concrete, ceramics, even
mineral pigments in some paints). These charges can become localized, or
trapped, and held there over significant time scales. Exposure to heat, light, or
high pressures can release the charges, which is often accompanied by a
detectable release of light. OSL provides therefore a useful tool for forensic
investigations and for tracking the former locations of a radioactive source. 38,39
Recent instrumental developments that can make this method more field
portable have been reviewed. 40
A study investigated the OSL response of electronic components found within
portable electronic devices such as cell phones and pagers, portable
computers, music and video players, global positioning system receivers,
cameras, and digital watches. The surface-mount resistors with alumina
porcelain substrates of such items consistently produced OSL following
gamma irradiation, allowing to determine whether such an object has been
close to a source. 41 The same useful property has been found for alumina-rich
electronic components from a USB flash drive. 42 It has even been shown that
some epoxy resins used to encapsulate electronic chips produce some OSL
effects. This is due to the silica used in some cases as filler in the resin. 43
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