Ion source development for ultratrace detection of uranium and thorium

NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS

卷:361

Article; Proceedings Paper

Liu, Y.¹  Batchelder, J. C.^1,2  Galindo-Uribarri, A.^1,3  Chu, R.^1,3  Fan, S.^1,3  Romero-Romero, E.^1,3  Stracener, D. W.¹ 

[1] Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA

[2] Oak Ridge Associated Univ, Oak Ridge, TN 37831 USA

[3] Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37966 USA

关键词: Ion source;    Surface ionization;    Laser ionization;    Uranium;    Thorium;   

DOI  :  10.1016/j.nimb.2015.04.081

来源: Elsevier

【 摘 要 】

Efficient ion sources are needed for detecting ultratrace U and Th impurities in a copper matrix by mass spectrometry techniques such as accelerator mass spectrometry (AMS). Two positive ion sources, a hot-cavity surface ionization source and a resonant ionization laser ion source, are evaluated in terms of ionization efficiencies for generating ion beams of U and Th. The performances of the ion sources are characterized using uranyl nitrate and thorium nitrate sample materials with sample sizes between 20 and 40 mu g of U or Th. For the surface ion source, the dominant ion beams observed are UO+ or ThO+ and ionization efficiencies of 2-4% have been obtained with W and Re cavities. With the laser ion source, three-step resonant photoionization of U atoms has been studied and only atomic U ions are observed. An ionization efficiency of about 9% has been demonstrated. The performances of both ion sources are expected to be further improved. (C) 2015 Elsevier B.V. All rights reserved.

【 授权许可】

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