Positrons in microtraps with long aspect ratios: Trap simulation and fabrication.
The positrons storage capacity of micro-Penning-Malmberg traps with large length to radius aspect ratios and radii of the order of tens of microns was explored. The new design of the trap consisted of an array of microtraps with substantially lower end electrodes potential. Simulation studies were conducted with WARP Particle-In-Cel I code. It was shown that each microtrap with 50pm radius, immersed in a 7T uniform magnetic field, stored positrons with a density of 1.6x[10.sup.11] [cm.sup.3] while the confinement voltage was only 10V. The charge clouds developed the expected radial soft edge density distribution and rigid rotation evolved to some extent.
The fabrication of large length to radius aspect ratio (1000:1) microtrap arrays involved deep reactive ion etching (DRIE) of silicon wafers to achieve through-vias. Smoothing the sidewalls through oxidation and chemical etching prior to gold sputtering ensured a complete coating during gold sputtering. Gold-coated wafers were then aligned and thermal compression bonded using an aligner jig. Positron confinement time depends on trap imperfections. We present the fabrication issues encountered and address geometry errors and asymmetries.
Alireza Narimannezhad, Joshah Jennings, Marc H. Weber, and Kelvin G. Lynn
Washington State University
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|Title Annotation:||56TH ANNUAL SYMPOSIUM OF THE IDAHO ACADEMY OF SCIENCE: THEME: ENERGY, MATERIALS, AND NANOTECHNOLOGY|
|Author:||Narimannezhad, Alireza; Jennings, Joshah; Weber, Marc H.; Lynn, Kelvin G.|
|Publication:||Journal of the Idaho Academy of Science|
|Date:||Dec 1, 2014|
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