Demonstration of a Radioisotope Power Source Using Promethium-147 Chloride and 4H-SiC Betavoltaic Cell
Abstract
Unattended, compact terrestrial and space sensors require power sources that have high energy and power density to continuously operate for 3 to 25 years depending on application. Currently, chemical sources cannot fully satisfy these conditions. Radioisotope power sources using --emitting radioisotopes have energy densities 1000 greater than chemical sources. Their power density is a function of - flux saturation in the planar (2-D) configuration, - emission range in the semiconductor converter, and betavoltaic (V) or beta-photovoltaic (-PV) cell geometry. Using state-of-the-art (SOA) 4H-SiC V cell and 2-D configuration, promethium-147 (147Pm) is the only --emitting radioisotope that can match power density with chemical sources while surpassing them in energy density. This approach to match power density while sustaining the unmatchable energy density is described. Promethium-147(III) chloride (147PmCl3) and 4H-SiC V cell were used for the 2-D configuration nuclear power source. The 147PmCl3 dried layers were sensitive to laboratory air moisture. The dried layers absorbed the external moisture and lowered the maximum power point (MPP) of the V cell. Moisture controllability through continuous heating during dispensing and placement in airtight enclosures during I-V curve measurements lessened the moisture absorption negative effects shown by increasing MPP. A total activity of 1,680 mCi/cm2 was deposited on a 4H-SiC V cell. A MPP of 3.2 W/cm2 was generated after source drying period. MPP saturation point was not reached at 1,680 mCi/cm2. This extrapolates to 6.4 W/cm2 of 147PmCl3 in between 2 4H-SiC making a battery packet and 64 W/cm3 with 10 packets at 1 cm2. At this power density, the nuclear power source could supply milliwatts to various sensors for at least 3 years continuously in a 1000 cm3 total volume.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 2021
- Accession Number
- AD1134455
Entities
People
- Brenda Smith
- Johnny Russo
- Marc Litz
Organizations
- United States Army Combat Capabilities Development Command