Direct Measurement of the <span class="aps-inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="italic">L</mi><mi>/</mi><mi mathvariant="italic">K</mi></math></span> Ratio in <span class="aps-inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mmultiscripts><mrow><mi>B</mi></mrow><mprescripts></mprescripts><mrow></mrow><mrow><mn>7</mn></mrow><mrow></mrow><mrow></mrow></mmultiscripts></mrow><mi>e</mi></math></span> Electron Capture

P. A. Voytas; C. Ternovan; M. Galeazzi; D. McCammon; J. J. Kolata; P. Santi; D. Peterson; V. Guimarães; F. D. Becchetti; M. Y. Lee; T. W. O'Donnell; D. A. Roberts; S. Shaheen

doi:10.1103/PhysRevLett.88.012501

Direct Measurement of the $L / K$ Ratio in ${}^{7}B e$ Electron Capture

P. A. Voytas, C. Ternovan, M. Galeazzi, D. McCammon, J. J. Kolata, P. Santi, D. Peterson, V. Guimarães, F. D. Becchetti, M. Y. Lee, T. W. O'Donnell, D. A. Roberts, and S. Shaheen

Phys. Rev. Lett. 88, 012501 – Published 18 December 2001

Abstract

The ratio of $L$ - to $K$ -shell electron captures in light nuclei is particularly sensitive to electron overlap and exchange effects. Calculations of these effects in $^{7} Be$ disagree by more than $20 %$ . We report a measurement of the $L / K$ ratio in $^{7} Be$ , using a cryogenic microcalorimeter which clearly separates $L$ - and $K$ -shell captures. The obtained $L / K$ ratio of 0.040(6) is less than half that of existing predictions for free $^{7} Be$ . The discrepancy is likely due to in-medium effects distorting the $L$ -shell electron orbitals.

Received 24 May 2001

DOI:https://doi.org/10.1103/PhysRevLett.88.012501

Authors & Affiliations

P. A. Voytas¹, C. Ternovan¹, M. Galeazzi², D. McCammon², J. J. Kolata³, P. Santi³, D. Peterson³, V. Guimarães³, F. D. Becchetti⁴, M. Y. Lee⁴, T. W. O'Donnell⁴, D. A. Roberts⁴, and S. Shaheen^4,5

¹Physics Department, Wittenberg University, Springfield, Ohio 45501-0720
²Physics Department, University of Wisconsin–Madison, Madison, Wisconsin 53706-1390
³Physics Department, University of Notre Dame, Notre Dame, Indiana 46556-5670
⁴Physics Department, University of Michigan, Ann Arbor, Michigan 48109-1120
⁵Physics Department, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia