By Heather Rock Woods
Literally tons of magnets are free for the taking by
groups at SLAC, Stanford and other DOE facilities.
The magnets ran SSRL’s storage ring until it was
dismantled in April to make way for SPEAR3, which will use more powerful
magnets to create brighter x-rays with higher photon flux. About 300 tons
of magnets, sitting on seven-ton concrete girders, were either rolled out
of the SPEAR tunnel or lifted out by crane in the few places where the
roof was removed.
SPEAR uses magnets to bend the path of electrons so they
can travel in the circular beam line, and to bend or wiggle the beam at
certain points to create the synchrotron x-rays used to investigate myriad
materials. The original SPEAR2 equipment, which also includes vacuum
chambers and ion pumps, is still in good working condition. The parts are
currently stored along the Klystron Gallery.
About 300 tons of magnets and other SPEAR2 equipment
are stored along the Klystron Gallery. (Photo by Diana
"This is material that may be useful at other sites," said
Roz Pennacchi (DO). SLAC hopes to find a project that can use the
materials while they are in good condition, she said.
Currently in suspension storage, these items can’t be
recycled or reused outside of SLAC or other DOE facilities because they
have been in a radiological area. "While a few items are radioactive, most
are not and none are dangerous," said Jim Allan of Operational Health
In January 2000, DOE began a suspension on recycling
metals from radiological areas (i.e., accelerator housings, radiation
areas, high radiation areas, radioactive materials areas)–even if they are
not radioactive. This suspension will last for at least another year until
uniform release standards are approved.
OHP tests items for radioactivity before they are turned
in to Salvage. Equipment exposed to beams where the energy is greater than
10 MeV (million electron volts) can potentially become radioactive, Allan
explained. The measurable levels of radioactivity are very low and pose no
danger. "The DOE threshold to determine if material is radioactive is
‘anything detectable above background (radiation levels) with our most
sensitive instrument,’" said Allan.
There are dozens of dipole bend magnets, quadrupole
magnets and sextupole magnets, as well as beam scrapers and kicker
modules. To see the full list of equipment, or visit the storage site,
please contact Alan Conrad, Property Control (Ext. 2329, alanc@SLAC.Stanford.EDU).