A project between Fernald EMP and LANL is to field a monitor for the detection of alpha-emitting contamination on a human body. Traditional personnel monitoring for alpha emitters involves either frisking with a probe or pressing against large detectors in order to overcome the short range of alpha particles. These methods have a low alpha collection efficiency, and can miss contamination on less accessible surfaces. We have investigated the sensitivity and practicality of measuring the entire subject simultaneously using the technique of ionization monitoring. The goal is to create a booth that personnel step into quickly during egress from radiological facilities. The detection technique relies on a breeze of air passing over the subject. Alpha emission produces copious ions in the ambient air which are transported by the air current to an ion collector, resulting in a small electrical current proportional to the amount of contamination. Results indicate a conservative sensitivity of 3000 disintegrations per minute localized to one of five areas of the body in a measurement lasting less than 2 minutes.

Facilities that may produce airborne alpha emitter contamination require a continuous air monitoring (CAM) system. However, these traditional CAMs have difficulty in environments with large quantities of non-radioactive particulates such as dust and salt. Los Alamos has developed an airborne plutonium sensor (APS) for the REBOUND experiment at the Nevada Test Site which detects alpha contamination directly in the air, and so is less vulnerable to the problems associated with counting activity on a filter. In addition, radon compensation is built into the detector by the use of two measurement chambers.

Decontamination and decommissioning (D&D) procedures consist of an assessment phase and a remediation phase. The primary problem during assessment is the location and identification of the contaminants. Identification is difficult in buildings because contaminants may be hiding in difficult-to-sample areas and systems. Detectors based on long-range alpha detector (LRAD) technology are useful during the assessment phase on piping and ventilation systems. Not only can these detectors identify alpha emitter contamination, they can also be used to identify uncontaminated systems/areas. (Subsequent operations can then be organized to prevent contamination of these systems.) The LRAD-based detectors are also useful during remediation to identify uncontaminated material, such as structural debris, foundations, and soil, that could not be checked earlier. Also of importance during remediation, is waste characterization for transportation and disposal because the radionuclides of the waste and their associated activity must be known. The LRAD-based detectors are well suited for bulk item characterization (i.e., concrete, debris, soil) because assay of the items can be done quickly without analytical delays. Some additional characterization may be required to identify radionuclides and their proportional distribution. Using the LRAD technology, we are currently building two types of detectors exclusively for D&D purposes. These are a concretemore » surface monitor and a pipe monitor.« less

There are numerous facilities, both within the US and in the rest of the world, within the complex of radiation laboratories and production plants where tritium has been released into the environment because of historic or ongoing mission-related operations. Many of environmental restoration projects have detected low levels of tritium contamination in local streams, ponds, and/or ground water. Typically these waters are moving or have the potential to move offsite and are viewed as a potential risk to the public and environment. Los Alamos National Laboratory will modify the well-proven long-range alpha detection (LRAD) technique for detection of ionizing radiation to optimize a system for detecting tritium in groundwater and other surfaces. The LRAD technique relies on detection of ionized air molecules rather than direct detection of ionizing radiation. The detected electrical current is proportional to the number of ionized air molecules present, which is in turn a measure of the amount of contamination present. Although this technique has been used commercially to measure alpha contamination on objects and surfaces, the technique is also ideal for monitoring low-energy beta particles. The authors have demonstrated beta detection using {sup 54}Mn, {sup 14}C, {sup 147}Pm, {sup 99}Tc, {sup 90}Sr, and {sup 36}Clmore » sources. Thus, the detector technology and detection of beta particles using this technology have both been demonstrated. The extreme short range of tritium beta particles necessitates an optimization of the detector system. In this paper, the authors will discuss these new designs.« less