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In this issue:
Safe '08: Safety Extends Beyond the Fenceline
Safety Today: Water that Christmas Tree!
Medical Care During the Holiday Shutdown
New SLAC Logo Items Just in Time for the Holidays
Public Lecture Tonight

SLAC Today

Tuesday - December 16, 2008

(Photo - safety team with LiH transport drum)
Left to right: Jerri Lynn Shoff, Olga Ligeti, Wendell Agot and Emilio Castro safely prepare hazardous materials for transport to off-site vendors. (Photo by Brad Plummer. Click for larger image.)

Safe '08: Safety Extends Beyond the Fenceline

Sometimes SLAC safety needs to extend beyond the lab grounds. This fall, the SLAC National Accelerator Laboratory Environment, Safety and Health Division contracted an outside vendor to safely treat and dispose of a cylinder of lithium hydride. The highly reactive solid can be treated and disposed of only at Environmental Protection Agency-permitted facilities, and it was up to SLAC Radiation Protection employees to find an authorized vendor with the expertise to dispose of the material appropriately after taking it off the SLAC campus.

When experiments require hazardous materials, they also require someone to manage any by-products. Radioactive Waste Group Leader Olga Ligeti manages the safe and proper handling and disposal of radioactive and mixed wastes for SLAC. The lithium hydride presented Ligeti with a unique challenge: the chemical is hygroscopic, meaning it reacts violently with water or moisture in air. Even a small amount of air will cause it to react, releasing hydrogen gas, which can ignite or possibly cause an explosion.

SLAC physicists used the lithium hydride years ago in an experiment to absorb low-energy photons preferentially, allowing high-energy photons through, a process called photon beam hardening. The chemical remained in a hermetically sealed cylinder under an inert atmosphere during its stay at SLAC. The cylinder, about four feet long and weighing less than twenty five pounds, could not be opened without strong cutting tools. However, since the material had been in the cylinder for several decades, internal erosion over the years could make the container fragile. From a safety standpoint, SLAC Radiation Protection Radioactive Waste group didn't want to risk keeping the lithium hydride in the cylinder any longer.  Read more...

(Column - Safety Today)

Water that Christmas Tree!

A National Institute of Standards video demonstrates the how quickly fire can develop when a dry tree is exposed to an open flame. (Click to see the video.)

If you are enjoying a Christmas tree as part of your holiday celebrations, providing the tree with plenty of water can help reduce the risk of a dangerous, fast-burning fire.

Although they are rare, Christmas tree fires represent a serious hazard. The National Fire Protection Association reports an estimated annual average of 210 home fires that begin with Christmas trees. Based on data from 2002 through 2005, these fires caused an average of 24 civilian deaths, 27 civilian injuries, and $13.3 million in direct property damage per year. On average, one of every nine Christmas tree fires resulted in a fatality. Further, 49% of Christmas tree fires spread beyond the room of origin and caused 94% of the associated fatalities.

The percentage of trees involved in structure fires represent an extremely small portion of the estimated 30 million Christmas trees sold in the United States each year. The moisture content of each tree can play a dominant role in determining the fire hazard the tree represents.

It is important to water your tree, to keep a high moisture content in the needles. This helps to limit any possibility of ignition and slow the spread of any fire that does start. A tree that has dry needles can readily ignite with a flame source, and can quickly generate dangerous heat levels. For some striking demonstrations, see these NIST videos.

Medical Care During the Holiday Shutdown

The SLAC Medical Department is closed during the holiday shutdown. As usual, if you have a serious injury, either you or the reporting party should call 911 and then call SLAC Site Security (x5555).

If you have a work-related non-emergency injury, you may seek treatment from one of the following healthcare providers.  Read more...

New SLAC Logo Items Just in Time for the Holidays

(Photo - new SLAC logo items)
New clothing, mugs, pens and more are available at the Stanford Guest House. (Photo courtesty of Doug Kreitz. Click for larger image.)

Looking for holiday gift ideas that are practical and support a good cause? Hoodies, sweatsuits, T-shirts, beverage mugs, pens and more sporting the new SLAC logo arrived over the weekend and are available for purchase at the Stanford Guest House (Building 49). Proceeds from sales of the logo items, made available by the Friends of the Linear Accelerator, help support FOLA donations such as benches and picnic tables for the SLAC campus. The Guest House Gift Shop is open 24/7 and will remain open throughout the holiday shutdown period. Call the shop with any questions (x2800).

Public Lecture Tonight

Tonight at 7:30 in Panofsky Auditorium, longtime SLAC physicist Greg Loew will present a trip through SLAC's origins, highlighting its scientific achievements, and provide a glimpse of the lab's future in "Big Machines and Big Science: 80 Years of Accelerators at Stanford." The talk is free and open to all.


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