Ciclotron
Design Study of a Compact Cyclotron for Accelerator Mass Spectrometry
tongEon Kim£
Research Institute and Hospital, National Cancer Center, Kyonggi 410-769
ghongEgheoul Yun nd winEoung Youn
National Center for Inter-University Facilities, Seoul National University, Seoul 135-703
onjong Wang
Centerfor Fusion Engineering, Korea Atomic Energy Research Institute, Daejeon 305-353
(Received 16 September 2008) An accelerator mass spectrometer (AMS) utilizing a small cyclotron has been designed. The system has a mass resolving power of over 4000, which is sucient to analyze a few AMS radioisotopes, including 14 C, for tracing or chronometric dating. The cyclotron can provide a high resolvingpower with a large number of turns and a high harmonic operation of the rf system and has the advantage of using both negative and positive ions in the analysis. A high transmission eciency is, in fact, a major goal in the design to compete with a Tandem AMS. A compact magnet with high stability, a sawtooth harmonic buncher and
at-topping rf system are the components adopted to achieve the goal.Also, large turn separations at injection and extraction are required, which can be done with adequate uses of the rst harmonic component of the main magnetic eld. The design of the cyclotron and injection beam line for the AMS has been studied.
PACS numbers: 29.20.Hm, 07.75.+h Keywords: Cyclotron, Accelerator mass spectrometer, Negative ion, Transmission eciency
I. INTRODUCTION
inethe development of the rdioron dting method y ernold nd viy ID the detetion tehnique of 14g hs dvned from ounting prtiles undergoing rdiotive dey proess to diret ounting with n elertor mss spetrometer @ewAF he high sensiE tivity of the ew shortens the ounting time from dys to tens of minutes y using muh smller smples omE pred to tht used in thedey 14 ounting methodF he diulties of interferene with x nd moleules like 13 grD 12 gr hving similr msses hve een resolved 2 y using negtive ions P nd gs stripping stge in ndemEeletrosttiEelertorEsed ew system QD RD respetivelyF he negtive eletron nity prohiits 14 x gs from forming negtive ions nd the stripping proE ess reks moleulr ions of 13gr nd12gr2 with smll inding energiesF e modern gs sputtering ion soure n provide high urrents of negtive ions SD ut needs to use solidied trgetsD whih demnds elorte eorts in grphitiztion nd few dys of preprtion for eh trgetF he iomedil ew @fewA my open possiilities
£ E-mail:
jwkim@ncc.re.kr; Fax: +82-31-920-0149
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