SPEAR3 Accelerator Approved for 500mA

Jun 02, 2006
The SPEAR3 beamline. Image courtesy of Peter Ginter
The SPEAR3 beamline. Image courtesy of Peter Ginter.

This spring the Department of Energy gave SPEAR3 license to run the accelerator at 500 milliamperes (mA), the current the accelerator was designed to use. Since it opened in January 2004, the machine has operated at 100 mA while beamlines were rebuilt with increased radiation shielding and optical components were upgraded to handle the increased beam power.

The fivefold increase in current translates into more photons shining on experimental samples, which will be especially helpful for protein crystallography studies.

Half an ampere (500 mA) may not sound like much compared to typical household currents rated at 15 to 30 A, but it’s the current multiplied by the voltage drop in an electrical circuit that determines how much power is produced. Each electron circulating in SPEAR3 loses more than a million volts on every turn around the ring. At 500 mA, the power radiated from the beam is close to 550 kW, the equivalent of 5,500 bright light bulbs.

"The challenge is to build vacuum chamber and beamline components that can take high power density," said Bob Hettel, head of the SSRL Accelerator Systems Department. "Most existing light sources operating near 3 GeV (billion electron volts) use no more than 300 mA, and usually much less. Building on experience gained from the B-Factory design, SPEAR 3 was the first 3-GeV light source designed for higher current, a trend that is now being followed in designs for new machines operating at that energy."

The machine has run at 500 mA several times already, with special permission from the DOE, to test the newly designed equipment and increased shielding. By the end of the 2006 summer shutdown, all beamlines except two will be capable of handling 500 mA. Beamline three has been decommissioned, and beamline four will be upgraded during the summer of 2007.

Initial testing has shown that the accelerator can maintain a stable beam at 500 mA. However, during the 2006-2007 run, SPEAR3 will operate at elevated current only a fraction of the time, with any beamlines not capable of 500 mA closed during those times.

Source: Stanford Linear Accelerator Center, by Heather Rock Woods

Explore further: Infrared imaging technique operates at high temperatures

add to favorites email to friend print save as pdf

Related Stories

Geologists solve mystery of Tibetan mountains

3 hours ago

In the most comprehensive study of its kind, University of Kansas geologists have unraveled one of the geologic mysteries of Tibet. The research, recently published online in Nature Geoscience, shows that i ...

Scientists help avert a nuclear medicine meltdown

Jan 09, 2015

University of British Columbia scientists have shown that small cyclotrons – particle accelerators the size of an SUV – can replace hulking nuclear power plants as the country's main source of medical ...

Recommended for you

New portable vacuum standard

4 hours ago

A novel Portable Vacuum Standard (PVS) has been added to the roster of NIST's Standard Reference Instruments (SRI). It is now available for purchase as part of NIST's ongoing commitment to disseminate measurement ...

Prototype for first traceable PET-MR phantom

5 hours ago

As cancer diagnostic tools, a new class of imagers – which combines positron-emission tomography (PET) with magnetic resonance imaging (MR or MRI) – has shown promise in the few years since these hybrid ...

Infrared imaging technique operates at high temperatures

Jan 23, 2015

From aerial surveillance to cancer detection, mid-wavelength infrared (MWIR) radiation has a wide range of applications. And as the uses for high-sensitivity, high-resolution imaging continue to expand, MWIR sources are becoming ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.