Ion Source Project

Project title: Collaborative AMS ion source development at University of California at Irvine, Woods Hole Oceanographic Institute/NOSAMS, University of Arizona, and National Electrostatics Corporation.

Grant: a proposal to NSF (EAR/IF) – under evaluation

Principal Investigator: John Southon, UC Irvine, 949-824-3674, jsouthon@uci.edu

Co-PI's: Mark Roberts, WHOI/NOSAMS, 508-289-3654, mroberts@whoi.edu and Warren Beck, Arizona, 520-621-4277, wbeck@physics.arizona.edu

 Project summary:

Three AMS laboratories either directly funded by NSF or with NSF-funded projects (UC Irvine, Arizona, NOSAMS at Woods Hole) currently use four versions of the National Electrostatics Corp (NEC) Cs sputter ion source. These laboratories and NEC will collaborate in a 2-year program to improve the ion source by modifying it for increased output, better reliability, and improved serviceability. The main goals of this work are to improve measurement precision and reliability, and to reduce instrument downtime associated with ion source maintenance. These two factors are the largest single causes of delay for users utilizing these facilities.

In Year 1, UC Irvine will concentrate on changes to the Cs feed and to the Cs and negative ion geometries aimed at increasing output and improving reliability. NOSAMS will investigate active pumping of the source and other vacuum improvements for increased output, and will redesign the extraction region for improved reliability. Arizona will implement improved internal mounting arrangements and alignment procedures leading to reduced servicing down time. A full suite of the modifications initially developed at each laboratory, including improvements implemented before this proposal, will then be evaluated, and an optimal set will be incorporated in Year 2 in the sources at the three institutions and in new sources produced by NEC. On grounds of convenience and low cost we will modify existing ion sources and test them on existing beam lines. 

The primary purpose of the three laboratories is to produce measurements of cosmogenic isotopes, primarily ¹⁴C, supporting local research at the parent institutions plus numerous external researchers. Improvements in measurement quality and turnaround time at our laboratories will thus have a very wide-ranging impact on research, and will strongly impact the studies of numerous graduate student and postdoctoral researchers who use the services of our laboratories. We will use conferences, publications, Web postings, our own personal contacts, etc, to ensure that the technical details and the benefits of such upgrades are also made available to the global AMS community as a whole.