4pi gamma-ray detection system

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This proposal will fund key upgrades to one of three principal stages of an overall system to measure toxic elements non invasively in human subjects. The overall project is in vivo neutron activation analysis (IVNAA) of the elements manganese (Mn) and aluminum (Al) in bone of human subjects. IVNAA involves a small controlled dose of neutron radiation (somewhat analogous to an x-ray or to a nuclear medicine scan). A few of the atoms of the target element (Mn or Al in this case) are made radioactive and this activity can be measured, resulting in a measurement of the amount of the Mn or Al present. The first stage is to produce neutrons, this is done in an accelerator, which is already present in the laboratory. The second stage is an irradiation cavity, this is also already available. The third stage is the detector array to measure the activity. There is an existing array, assembled from parts acquired from another laboratory that was decommissioning another instrument. Some of the individual detectors in that re-commissioned array are no longer performing well. This funding is primarily to replace the two detectors that are not functioning well. This will enhance the performance of the whole array. It is important to measure these elements. Mn is essential, but in excess it is toxic. The relationship between exposure to Mn in the workplace, resultant stored levels in bone and then possible health effects is not at all well known. Similarly, Al is toxic, with harmful effects on normal bone function. There is also continuing controversy as to whether Al can play a part in the causation of Alzheimer's Disease. Being able to measure stored levels of these elements in bone will contribute towards a better understanding of the health impact and then to preventing harm.