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In this issue:
Calming the Wakefield
Yulin Chen to Receive Spicer Young Investigator Award
Chemical Purchase Reviews Updated
SLAC Green Note: Do Screen Savers Save Energy?

SLAC Today

Thursday - September 10, 2009

Calming the Wakefield

(Image - wakefield simulation)
A snapshot of a simulation of the wakefield generated by a particle bunch moving through a series of ILC cavities, from three different perspectives. The colors represent the magnitude of the fields, with warmer colors representing the strongest fields. (Image courtesy ISGTW.)

For the International Linear Collider to run at maximum performance, each of its 27,000 cavities must be designed as precisely as possible. It is very time consuming and costly, however, to produce physical prototypes, so researchers at SLAC National Accelerator Laboratory decided to use a supercomputer to create and test virtual prototypes of the cavities.

The ILC, which is in its design phase, will use superconducting cavities to accelerate electrons and their antimatter partners, positrons, to nearly the speed of light before colliding them. By studying these collisions, researchers will be able to probe more deeply into the subatomic world.

As particle bunches travel through the accelerator cavities, they produce electromagnetic wakes behind them, much like the waves left behind as a speedboat races across the water. These wakefields interfere with bunches that follow, causing some particles to stray off course, degrading the electron beam's quality. The wakefields also produce heat that can damage cavities and cause the accelerator to malfunction.

The more powerful the beam, the stronger the wakefield. And with expected collision energies of around 500 billion electronvolts, the ILC definitely has the potential to produce strong wakefields.

"From our simulations, we can measure the wakefield and modify the cavity's design until it is within a certain limit," said SLAC researcher Cho Ng. "By doing this, you can bypass the process of developing a prototype several times and reduce cost."  Read more in International Science Grid This Week...

Yulin Chen to Receive Spicer Young Investigator Award

(Photo - Yulin Chen)
Yulin Chen.
(Photo courtesy Yulin Chen.)

Physicist Yulin Chen of the Stanford Institute for Materials and Energy Science has been awarded the 2009 William and Diane Spicer Young Investigator Award. The award, named for Stanford professor and SLAC researcher William Spicer (1929–2004), and his wife Diane, who passed away in 2009, is given to an early career researcher whose work has benefited from or is beneficial to the Stanford Synchrotron Radiation Lightsource or the overall lightsource community.

"I am very glad that our work was acknowledged," Chen said of the award. "I feel very excited not only because of the prize itself, but also because we could demonstrate the great opportunity SSRL provides for science. I hope the lab will keep developing its remarkable capabilities for experiments and become an even better platform for more exciting science to be carried out."

The award will be presented at the October 19 SSRL/Linac Coherent Light Source Annual Users' Meeting at SLAC. The award includes a certificate and monetary gift of $1,000. In turn, Chen will give a short presentation describing his work.  Read more...

Chemical Purchase Reviews Updated

SLAC is implementing a new Environment, Safety & Health Division review process for the addition of new chemicals to the Haas tcmIS chemical catalog. The new process will help to ensure that appropriate controls are identified and are in place prior to the delivery of the ordered chemical. In addition, in support of the chemical reduction goals of Executive Order 13423, chemicals will be reviewed to help identify whether there may be an opportunity for purchasing a safer, less toxic product. For example, for industrial chemicals like cleaners, 'greener' alternatives are now readily available and easy to find through certifying organizations like Green Seal.

Though the new review process is similar to the existing process, it will be more formal and require a three-day review period for new catalog add placements. There will be flexibility for time critical situations. In addition, for purchases of highly toxic or dangerous chemical products, a Toxic and Hazardous Chemical Justification Form may need to be completed by the chemical requester. The full policy appears in the ES&H manual Chapter 40: Hazardous MaterialsRead more...

(Image - ISEMS leaves)

SLAC Green Note:
Do Screen Savers Save Energy?

Screen savers, originally designed to prevent images from being "burned" on to the screen, use the same energy as if the monitor was in full power mode, and may actually use more energy if graphics-intensive images are used. Modern LCD monitors do not need screen savers.

Here are some desktop energy savings tips:

  • Keep power management features enabled. (Energy Star labeled computers and monitors only save energy when the power management features are activated.)
  • Set monitors to go into sleep mode within 5 to 20 minutes of inactivity; a blank screen and reduction in power consumption characterize this mode.
  • Turn off your monitor at the end of the day using the power switch, located in lower right corner of most monitors.
  • Turn off peripherals such as external speakers and personal printers when not in use. (Peripherals still use energy in standby mode.)
  • Only purchase EPEAT registered and Energy Star rated computers and monitors (mandated for all federal agencies).
  • Replace CRT monitors with LCD monitors. (LCD monitors use about half as much energy as CRTs).

See also these additional energy saving tips for home office and home electronics.

For assistance in setting power management features, contact your Department's computer administrator.


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