Portable sampling devices materials used

Besides EDXRF spectrometers that are intended for use in the laboratory, a number of portable EDXRF instruments are also available. These devices are used in various fields for on-site analysis of works of art, environmental samples, forensic medicine, industrial products and waste materials etc. In their simplest form, the instraments consist of one or more radioisotope sources combined with a scintillation or gas proportional counter. However, combinations of radio-sources with ther-moelectronically cooled soHd-state detectors are also available in compact and lightweight packages (below 1 kg). In Fig. 11.21, schematics of various types of radiosource based EDXRF spectrometers are shown. In Fig. 11.21a, the X-ray source is present in the form of a ring radiation from the ring irradiates the sample from below while the fluorescent radiation is efficiently detected by a solid-state detector positioned at the central axis. Shielding prevents radiation from the source from entering the detector. In Fig. 11.21b and c, the X-ray source has another... 

An estimated 2.8 million capacitors are in use in the USA. About 2000 of them rupture every year, causing spillage into the environment. As in the case of transformers, there are no tools to predict capacitor failure. Soil samples have to be tested for contamination, and the solid PCB-containing material must be shredded prior to incineration. The utility industry considers it to be cost-ineffective to recover the part/parts of the contaminated capacitors. Portable screening devices such as x-ray fluorescence meters for transformer oil, acoustical detectors to detect the ultrasonic sound from a faltering capacitor, and an infrared scanner to measure the temperature-rise of the faltering capacitor have been studied in the field (Miller, 1982). 

Monitoring requirements have been covered in the section on occupational exposures for adult employees. In addition to personnel monitoring, surveys are required. The surveys can be done with portable instruments or samples can be obtained and tested in laboratory instruments. These surveys are used to evaluate (1) the extent of radiation levels, (2) concentrations or quantities ofradioactive materials,and(3)thepotentialradiologicalhazardsthatcould be present. The equipment used for the surveys must be calibrated periodically for the radiation measured. Normally this is doneatleastannually.A description of personnelmonitoring and survey devices will be found later in this chapter, and recommended survey procedures. 

---