High-sensitivity measurement of He 3 − He 4 isotopic ratios for ultracold neutron experiments
/ Authors
H. Mumm, M. Huber, W. Bauder, N. Abrams, C. Deibel, C. Huffer, P. Huffman, K. W. Schelhammer, C. Swank, R. Janssens
and 8 more authors
C. L. Jiang, R. Scott, R. Pardo, K. Rehm, R. Vondrasek, C. O'Shaughnessy, M. Paul, L. Yang
/ Abstract
Research efforts ranging from studies of solid helium to searches for a neutron electric dipole moment require isotopically purified helium with a ratio of ^3He to ^4He at levels below that which can be measured using traditional mass spectroscopy techniques. We demonstrate an approach to such a measurement using accelerator mass spectroscopy, reaching the 10^(−14) level of sensitivity, several orders of magnitude more sensitive than other techniques. Measurements of ^3He/^4He in samples relevant to the measurement of the neutron lifetime indicate the need for substantial corrections. We also argue that there is a clear path forward to sensitivity increases of at least another order of magnitude.
Journal: Physical Review C