Abstract :
The 15UD Pelletron accelerator at Nuclear Science Centre, New Delhi is being developed for Accelerator Mass Spectrometric studies in addition to usage in basic Nuclear Physics, Materials Science, Atomic Physics, Radiation Biology etc. The new additions to the facilty, for AMS studies, include a multi-cathode ion source, recirculating turbos at the terminal for gas stripper, an offset Faraday cup after analyzer magnet, a Wien filter, a new quadrupole system, double slits and a multi-anode gas detector. The Multi-cathode SNICS source procured from NEC,USA has 40 cathode positions and can be moved both ways. A remote control system , with locally developed software, is used so that cathode positions can be changed by the operator from control room. The recirculating gas stripper system is based upon two 250 l/s turbo pumps mounted in the terminal and nitrogen gas is used as stripper. For molecular beams such as BeO, a combination of foil and gas stripper yields the best results. A maximum transmission of 19% has been achieved with foil and gas combination for BeO , with 9Be in 3+ charge state at a terminal potential of 11MV. The emphasis is on measurement of 10Be with planned later developments on studies with 26Al and 36Cl. Standard BeCl2 solution , SRM4325, has been procured from NIST,USA in liquid form. Standard chemical techniques have been used to convert it to BeO powder, which was then mixed with Nb powder and pressed into cathode. The simultaneous injection method for detecting 10Be (3+) in the gas ionization detector with 17O(5+) from 9BeO, detected in the offset Faraday cup after the analyzing magnet , is being used. A gas cell was put before the multi -anode gas detector and nitrogen gas at 220 mb pressure was used to stop the 10B in the gas cell. A pressure of 30 mb was used in the ionization detector to detect 10Be. In addition to 10Be, which was very well separated, patches of 7Be, and 4He, presumbaly caused by the incident 10B could be seen. Measurements have been carried out on this 10Be standard and results agree within 5% to known measured values for SRM4325. Geological samples will be presently analyzed. A description of the facility and the method of measurement are being presented.
PACS: 07.75+h;41.85 Keywords : AMS,10Be
See more of Poster Session I
See more of The 10th International Conference on Accelerator Mass Spectrometry (September 5-10, 2005)