Since 1970s CNL has been providing industry and government agencies access to the variable energy 76" isochronous cyclotron. The cyclotron can accelerate protons from 1MeV to 68MeV. In the Radiation Effects Facility (REF), the maximum proton energy to the Device Under Test (DUT) is 66MeV.
The spatial spreading of the beam is accomplished by passing the beam through a Ta diffuser foil. Lower energies can also be obtained by choosing a cyclotron proton energy combined with a proper diffuser foil to give an acceptable beam energy spread. Typical the beam energy spread is kept below 600KeV. In the REF the flux can be in the range of 1 to 1x1010 p/cm2 s, although typical beam fluxes for exposing electronics are 1x104 to 1x109 p/cm2 s.
For this beam line the diameter of the beam spot can be up to 6 cm, with a uniformity of 92 %. A second beam line, 1C, has recently become available for higher flux beams, up to 1x1012 p/cm2-s, but with a beam spot of 2 cm in diameter. A compound x-y table (24"x 36") is provided for locating the DUT, the range on translation is 7.37" and 19.59" in the X and Y direction respectively (this table can also be remotely controlled); two laser beams are used to align positioning of the DUT within the beam. A vacuum
box 16.5" X 16.5" and 25" tall can be attached at the end of the REF beam line to use cyclotron proton beams lower than 7MeV without subjecting them to the energy spreading due to the exit foil or the air path.
Beam dosimetry is accomplished by means of a secondary electron emission monitor (SEEM) combined with a removable Faraday Cup. Beam uniformity is monitored with a segmented secondary electron emission monitor (SSEEM).
The facility is available ~12 months/year (there are two shutdowns, one in January and the other in July, each one 2 weeks long). Previously to schedule beam time an agreement with the University of California has to be secured.
| DUT Specification: |
| Table Dimensions: |
24" x 36" |
| Range of translation: |
X: 7.37" |
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Y: 19.59" |
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Z: xx" |
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For additional information on the REF or to schedule an experiment please contact Dr. Carlos Castaneda:
- Tel: +1 (530) 752-4228
- Fax: +1(530) 752-0952
- E-mail: castaneda@crocker.ucdavis.edu
- Mail: Crocker Nuclear Laboratory University Of California One Shields Avenue, Davis CA 95616-8569