Hiroshi Saeki - Analysis for a charged microparticle from an ion pump to trap at low electric field with high enhancement factor

Version 1

      Publication Details (including relevant citation   information):

      Rev. Sci. Instrum. 65(11), 3479 - 3481 (1994).

      PACS:

                                                         
            29.20.db              Storage rings and colliders      
            41.20.Cv              Electrostatics; Poisson and Laplace equations,         boundary-value problems      

      Abstract:

      An experiment using a wire simulating an electron beam was   carried out in atmosphere to find organic particles (5‐μm   thickness collected from an ion pump) trapped in a low electric   field. It was found that these needlelike charged flakes stood   upright at the bottom surface of the beam chamber without applied   electric field. In spite of large adhesive action between the   particle and the inner chamber surface in air, it was also found   that the sample microparticles were trapped at the low electric   field of 2525 V/m. Furthermore, the measured charge on the   samples ranged from 1×10−13 C to 3×10−13 C. Our new theoretical   analyses for the samples show that the electric field acting on   the needlelike microparticles is enhanced approximately   104  times from the results of the atmospheric experiment, and that   the charged particles in vacuum can be trapped at a lower   electric field of 70 V/m in the TRISTAN accumulation ring (time   average electric field at the beam current of 30 mA) because of   weak adhesion between the particles and an inner chamber surface   rather than that in atmosphere. Therefore, microparticle trapping   phenomena can be caused by such a charged particle coming from an   ion pump or a distributed ion pump used in an electron   accelerator.

      Address (URL): http://rsi.aip.org/resource/1/rsinak/v65/i11/p3479_s1