PARTICLE TRACKS

HIGH ENERGY NUCLEAR PARTICLES, PARTICULARLY FISSION FRAGMENTS, LEAVE A DAMAGE TRAIL IN DIELECTRIC MATERIALS SUCHAS GLASS OR POLYCARBONATE PLSTICS. UNDER CERTAIN CIRCUMSTANCES, THESE DAMAGE TRAILS CAN BE MADE VISBILE BY CHEMICAL ETCHING WHICH PROCEEDS PREFERENTIALLY ALONG THE PARTICLE TRACK TO PRODUCE AN ETCH PIT. DATING OF NATURAL MATERIALS BY COUNTING THESE ETCH PITS HAS BEEN RESTRICTED TOFISSION FRAGMENTS BECAUSE INORGANIC GLASSY MATERIALS ARE NOTSUFFICIENTLY SENSITIVE TO REGISTER PARTICLES OF SMALL ATOMICNUMBER. THIS PROPOSED WORK WILL TEST THE FEASIBILITY OF ARTIFICIALLY ENHANCING THE SENSITIVITY OF NATURAL MATERIALS TO THE POINT OF REGISTERING ALPHA PARTICLES PRODUCED BY RADON DECAY DAUGHTERS. NATURALLY OCCURING RADON GAS PERCOLATES UP THROUGH THE SOIL AND CONTACTS THE EXPOSED SURFACE OF A LITHIC TOOL OR FLAKE. THE ACCUMULATED ALPHA TRACKS ON SUCH A SURFACE, SHOULD THEN INDICATE WHEN THE ARTIFACT WAS HANDLED OR DISCARDED AS OPPOSED TO THE FISSION FRAGMENT INDICATION OF WHEN THE MATERIAL WAS FORMED. PREVIOUS WORK WITH HIGHLY SENSITIVE PLASTICS INDICATES THAT DOSES OF RADIATION IN THE 106 RAD RANGE, ELECTRIC POTENTIALSAND VERY SLOW ETCHING CONDITIONS MAY ENHANCE THE CONTRAST BETWEEN BULK ETCH RATES AND PARTICLE TRACK ETCH RATES. TESTS OF SUCH TREATMENTS WILL BE CONCENTRATED ON MATERIALS SUCH AS OBSIDIAN, CHERT, AND ARGILLITE, COMMONLY USED BY PREHISTORIC CULTURES FOR TOOL MANUFACTURE. CURRENTLY MEASUREMENTS OF SURFACE HYDRATION INDICATE AGE SINCE MANUFACTURE, BUT THIS METHOD IS SOMETIMES UNRELIABLE DUE TO VARIABILITY IN MOISTURE AND PROPERTIES OF THE MATERIAL. RADON PERCOLATION IS A RELATIELY CONSTANT PROCESS IN MOST AREAS AND PARTICLE COUNTING SHOULD BE LESS DEPENDENT ON THE MATERIAL ONCE THE REGISTRATION THRESHOLD HAS BEEN EXCEEDED.