Parametric Study of Americium Thickness for Alphavoltiac Device Electrical Power Optimization

Author(s):

Benjamin Cohen, Owen Li, and Marc Litz

Abstract:

Alphavoltaic (AV) energy conversion, in which an alpha particle flux from radioisotope sources such as 241Am is converted into electrical power, offers the promise of a higher power output as compared to the more established betavoltaic systems. First, a comparison of beam and layer geometry into aluminum gallium nitride (AlGaN) is described. The beam-delivered alphas describe experimental configurations using a Pelletron accelerator while a layer of americium (Am) deposited on a 1-cm2 energy converter describes final use configuration. We investigate the geometry (layer thickness) of 241Am to maximize power transferred into the semiconductor target (AlGaN) describing an AV persistent power source. Identical studies were conducted for pure Am as a foil, AmO2, AmCl3, Am(NO3)3 for comparison. Alpha particles exposing AlGaN semiconductor structures generate electron hole pairs creating a continuous and persistent trickle charge of electrical power. Pure 241Am foil provides the highest power into the AlGaN at 10.37-µm source thickness. Most AlGaN diodes have an active charge collection of 2 µm. AmO2 with a thickness of 6.96 µm delivers 68 µW to the active charge collection depth (first 2 µm) of AlGaN.