Frances Pleasonton

Frances Pleasonton (1912–1990) was a Particle Physicist at the Oak Ridge National Laboratory. She was an active teacher and researcher, and a member of the team who first demonstrated neutron decay in 1951.

Frances Pleasonton
ORNL’s Arthur Snell and Frances Pleasonton with a device to count neutron decays
Alma materBryn Mawr College
Known forNeutron decay
Scientific career
InstitutionsOak Ridge National Laboratory

Early life and education

Pleasonton earned her Bachelor's degree at Bryn Mawr College.[1] She was an editor of the Bryn Mawr College yearbook.[2] She went on to teach at Winsor School, Girls Latin School of Chicago and Brearley School.[1] She returned to Bryn Mawr College for her Master's degree, working as a Warden at Pembroke East, and graduated in 1943.[1][3] She was demonstrator-elect in physics and took a leave of absence for government service in 1942.[3] During her Master's degree she identified the crystal structure of Rochelle salt.[4]

Research

Pleasonton was an active researcher in neutron decay.[5] There were several attempts to measure neutron half-life before the second world war, all of which failed due to the lack of availability of intense neutron sources.[5] Arthur Snell and Leonard Miller built the Oak Ridge Graphite Reactor, which could focus beams of neutrons and allow scientists to observe their decay.[5] They measured the half-life of a neutron in 1951.[6] Pleasonton was supported by the United States Atomic Energy Commission and published broadly.[7][8][9] In 1958 they examined the decay of helium-6, Pleasonton and Snell monitoring the directions of neutrinos and electrons.[10] This result confirmed the electron-neutrino theory of beta decay.[6] In 1973 she authored several sections of the report for the Nuclear Regulatory Commission.[11] At Oak Ridge National Laboratory, Pleasonton's laboratory was visited by the Queen of Greece and the King of Jordan.[10] Pleasonton went on to study the ionisation of xenon x-rays.[12]

Pleasonton remained in Tennessee after her retirement from Oak Ridge National Laboratory and was involved in citizens groups to protect the environment.[13]

References
  1. College, Bryn Mawr (1944). Bryn Mawr College Calendar. Bryn Mawr College.
  2. "Bryn Mawr College Yearbook. Class of 1934". Bryn Mawr College. Retrieved 2018-06-15.
  3. Bryn Mawr College (1944). Bryn Mawr College Calendar, 1943-1944. Special Collections Bryn Mawr College Library. Bryn Mawr, PA: Bryn Mawr College.
  4. Pleasonton, Frances (1944). "A Model of the Structure of Rochelle Salt". American Journal of Physics. 12 (1): 19–22. Bibcode:1944AmJPh..12...19P. doi:10.1119/1.1990525.
  5. "The short life of a neutron | ORNL". www.ornl.gov. Retrieved 2018-07-15.
  6. "History of Fundamental and Applied Sciences Achievements in Oak Ridge National Laboratory: Nuclear Physics and Astrophysics – Discovery of America by Queltanews - Technopark QUELTA". tp.quelta.com.ua. Archived from the original on 2018-07-15. Retrieved 2018-07-15.
  7. Pleasonton, Frances; Snell, A. H. (1957-08-07). "Ionization following internal conversion in xenon". Proc. R. Soc. Lond. A. 241 (1225): 141–152. Bibcode:1957RSPSA.241..141P. doi:10.1098/rspa.1957.0119. ISSN 0080-4630. S2CID 94933142.
  8. "Fragment-mass and kinetic-energy distributions from the spontaneous fission of $sup 246$Cm | Sci-napse | Academic search engine for paper". Scinapse. Retrieved 2018-07-15.
  9. Pleasonton, Frances (1973-10-15). "Prompt γ-rays emitted in the thermal-neutron induced fission of 233U and 239Pu". Nuclear Physics A. 213 (2): 413–425. Bibcode:1973NuPhA.213..413P. doi:10.1016/0375-9474(73)90161-9. ISSN 0375-9474.
  10. Bienlein, J.K.; Pleasonton, Frances (1962-08-01). "The half-life of He6". Nuclear Physics. 37: 529–534. Bibcode:1962NucPh..37..529B. doi:10.1016/0029-5582(62)90288-2. ISSN 0029-5582.
  11. Perey, F. G. (1973). "Report to the US Nuclear Data Committee". OSTI. doi:10.2172/4469547. Retrieved 2018-07-15.
  12. Proceedings of the Royal Society of London: Mathematical and physical sciences. Harrison and Son. 1957.
  13. "TENNESSEE CITIZENS FOR WILDERNESS PLANNING" (PDF). 1981-11-09. Retrieved 2018-07-15.
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