IniFial trapping process of ultra slow antiprotons

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The present research project were primarily planned for two years combined with Grant-in-Aid for Scientific Research to construct a transport beamline for ultra slow antiprotons. However, the project was approved only for the first year, which makes it very difficult to keep the consistency over the whole project.The purpose of the project has been to prepare a transport beamline for ultra slow antiprotons extracted from a Penning trap which is installed at LEAR (low energy antiproton ring) of CERN,which enables, for the first time, to investigate the initial trapping processes of antiprotons into atomic orbitals under single collision conditions.Because of the limited time, we have, in the first stage, tried to find a way of cooling trapped antiprotons efectively, and then to optimize the extraction condition of slow antiprotons from the trap. In measuring the annihilation rate of antiprotons in the trap, one can estimate the capture cross section of antiprotons into atomic orbitals of the residual gas, which has been believed to be inversely proportional to the velocity of antiprotons, i.e., the annihilation rate stays constant. However, our experiment shows that the rate increases at the beginning of the cooling, and then start to decrease, which is a clear indication that the capture cross section saturates in the low velocity region or even decreases when the velocity decreases. The present project proceeds satisfactorily without any serious problem except for some delay originating in accelerator troubles. Now we believe that we are ready to make the major part of the proposed experiment successfully for the coming fiscal year, i.e., the beamtime is allocated almost every day from April to September, the beamline is sent out to CERN,etc. It is noted however, that the proposal asking continuation of the support to visit CERN has been rejected.