Design and construction of a one-dimensional particle tracker for measurement of alpha particle stopping power

Abstract

The energy deposited by a charged particle in a medium is non-uniform and peaks near the end of the particle’s path. The energy deposition through the medium is known as stopping power and the shape of this function is called the Bragg curve. Stopping power is typically calculated from first principles rather than measured due to the difficulty of doing so. A one-dimensional particle tracker using gas electron multiplier technology was designed and constructed to directly measure the stopping power at 16 discrete points along the path of alpha particles emitted by 241Am. The use of tissue-equivalent gas allows the results to be compared to those expected within tissue. The results obtained show that the detector concept has merit, although there is room for improvement. In particular, certain voltages and electric field strengths have room for optimization, and more sophisticated readout electronics could be used to reduce experiment run time.