PROTON MICROPROBE FOR TRACE ELEMENT ANALYSIS OF TISSUE

质子微探针对几种人体微量元素的研究进展

Recent proton microprobe studies on trace elements in several human disorders have shown the superiority of the proton as compared to the electron microprobe. This has been dramatically demonstrated in the studies of aluminum in Alzheimer's disease. The objective of the Phase I work was to design a beam-focusing system with 0.3 micron resolution (comparable to an electron microprobe) and at least 100 picoamperes of current. These goals have been surpassed, and we can achieve 0. I microns resolution with at least 100 picoamperes of current. The objectives of the Phase II work are to complete an engineering design of the system, acquire all components, assemble the system and test it in all regards other than with a beam in our laboratory. The focusing system will then be installed at the University of Florida Van de Graaff accelerator and commissioned with the 2.5 MeV proton beam. Aberrations and resolutions will be measured and optimized respectively. Preliminary measurements with biological tissue will be performed to establish scan rates that produce acceptable tissue damage. This instrument, with 3 times greater spatial resolution and 100 times greater elemental sensitivity than an electron microprobe, has superior potential for breakthroughs in many areas of research in biology and material science.