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Electrostatic Focussing Lens*

Author: Eric Thomas
Requested Type: Poster Only
Submitted: 2011-08-11 14:17:06

Co-authors: D. Hopkins, F. Betton

Contact Info:
School of Science & Technology
Room 120 AERB, Box 352250
Seattle, WA   98195
USA

Abstract Text:
We developed an electrostatic focusing lens capable of generating DD reactions, by focusing deuterium ions generated from a pointed emitter at a frozen heavy water target. Due to difficulty with the pointed emitter, we later switched to a hollow cathode design. In addition to the DD experiment, two exposed metals where analyzed by an electron microscope to determine the possible application as shielding material.

To model the lenses, chamber, and calculate the dimensions for the design that would maximize ion energy and density, the program SIMION was used. Lens dimensions were calculated and machined at a machine shop.

During stable operation, the vacuum was hand adjusted to 10-13 mTorr. To keep a stable beam, a DC voltage generator was varied between 15-25kV. Hand adjusting was necessary because at points in the operation the frozen heavy water would release vapor at an increased rate. This caused the pressure to rise and the beam current to spike, creating instabilities and an arc to the lens.

Three methods were used to determine successful DD reaction. (1) Two differently shielded Geiger counters (unshielded and UHMW-PE insulated tube), (2) Spectrophotometer comparing control peaks with heavy water tests, and (3) a calibrated bubble dosimeter specific to neutrons. Analysis of the results suggest that neutrons where emitted during operation. Neutron flux varied from 532 to 1.4x10^6 neutrons/ sec, and require further tests to plot and narrow results.

*We are graduating High school students, that recently won 1st at the Intel International Science Fair and presented our project to President Obama. Please email us with any questions, comments, and suggestions you may have.

Characterization: A1

Comments:

University of Washington

Workshop on Innovation in Fusion Science (ICC2011) and
US-Japan Workshop on Compact Torus Plasma
August 16-19, 2011
Seattle, Washington

ICC 2011