DESIGN CONSIDERATIONS FOR A FUTURE INJECTION SYSTEM FOR RADIOCARBON AMS MEASUREMENTS

In planning for a possible upgrade to the Oxford AMS system (dedicated to C-14 measurements), we have given thought to novel as well as conv entional designs of injection which achieve both a high level of accur acy and also permit C-14 detection with negligible background due to m isidentification. Experiments at Oxford in which sputtered beams from graphite are directly injected (no mass separation) give limits on the sufficient mass resolution to achieve unambiguous C-14 detection. The se will be discussed. Our experience with the CO2 source indicates tha t space charge effects can become the dominant problem in achieving is otope ratio measurement accuracy and we believe should be taken into a ccount in the design of high beam current systems. We will outline pos sible designs for a new system with these effects in mind. In particul ar, we hope to present a feasibility study for a pulsed magnet design.