For certain reasons, SMCAMS (Shanghai Mini-Cyclotron based Accelerator Mass Spectrometer) has missed AMS-9 in Japan for reporting its status. However, in fact, to make such a unique mini-cyclotron AMS facility more applicable, continuous improvement efforts have never been quitted since we reported the first successful measurements for unknown 14C samples on it in AMS-8[1]. Several upgrade programs have been carried out on SMCAMS in the last few years. A pneumatic multi-cathode Cs sputter negative ion source with 24 sample positions was developed and put into use, which allowed us to change samples automatically and more rapidly. A high sample positioning precision similar with that of commercial one was achieved. The features and performances of this homemade device will be introduced in this paper. A new control system based on RS-485 multi-drop network was also established to automatically control the sequential accelerations and measurements of different C isotopic ions and routine operations, which finally also led to the multi-sample automatic measurement without intervene. Its better reliability and stability has been demonstrated in the routine operation. The efforts were also made improve the consistency and quality of the sputtered samples by designing a series of sample-pressing tools. More than 200 unknown 14C AMS samples (archaeology, geology and biomedicine et al.) have been measured on the upgraded SMCAMS soon before. All the above will be described in this paper, as well as some mini-cyclotron AMS specific problems ever encountered and considerations.
See more of Poster Session I
See more of The 10th International Conference on Accelerator Mass Spectrometry (September 5-10, 2005)