SLAC Today is available online at:
In this issue:
Catch and Release: Fishing for Barium Ions
Director's Column: Greetings
Delays on Loop Road
Holiday Giving Campaigns at SLAC
Safety Firsts

SLAC Today

Monday - December 4, 2006

Catch and Release: Fishing for Barium Ions

Peter Rowson examines a vacuum system containing a liquid xenon cell, which was used to test cryogenically cooled "fishing poles." (Click on image for larger version.)

How do you identify the rare thing you're looking for in a vast sea? Go fishing.

Researchers on the Enriched Xenon Observatory (EXO) project, including a group from SLAC, are currently developing ways to catch barium ion "fish" from inside a multi-ton vessel of liquid. They then remove the ions from the liquid and release them from the fishing pole so they can be identified as barium.

A barium-136 ion is the unmistakable sign that somewhere in the sea of xenon-136, a xenon atom underwent radioactive decay. If the two electrons released from that decay have a particular energy, scientists will have hooked the proof that neutrinos are their own anti-particle—an exciting but unproven idea. The observation will also give EXO a way to measure the scanty mass of neutrinos.

The radioactive decay normally emits two neutrinos as well, yet ironically, finding a decay with no neutrinos is what will tell scientists that neutrinos and anti-neutrinos are the same thing. In "neutrinoless double beta decay," the electrons carry all the decay energy otherwise shared with the neutrinos.

Fishing for barium will help the experiment separate the real fish from spurious fish—electrons in the right energy range that come from other sources, such as natural radioactivity and cosmic rays.  Read more...

(Director's Column)

As you all read in the message from Jonathan in SLAC Today last week, I will be assuming the role of Acting SLAC Director during the next two months while Jonathan is away on sabbatical. This includes all of the Director's responsibilities both inside the laboratory and in relation to Stanford and the Department of Energy (DOE), apart from matters that relate to Particle and Particle Astrophysics faculty and governance. This area will be the responsibility of Persis Drell. It is a privilege to serve the laboratory and all of you in this temporary capacity. I would like to assure you that SLAC's senior management team will continue to work together with me to manage the day-to-day needs and longer term activities of the lab. I plan to continue the tradition of writing weekly Director's Columns for SLAC Today. Communication from senior management to the staff is something which I feel is extremely important and I will keep you up to date on management decisions and activities that might impact all of our daily work and future.

Besides introducing myself in this, my first column, I would like to comment on two very recent oversight activities. Last Thursday was the closeout of the review and inspection by the DOE Office of Independent Oversight (OIO). The OIO team was on site for an extended period and interacted with many of our staff. Their visit was facilitated by staff acting as "points of contacts" for a number of areas at SLAC and many staff were involved in providing extensive documentation and information. I would like to personally thank all of you for your extraordinary help, effort and cooperation in allowing the OIO team to carry out their review. We will be receiving the formal report early in the new year and developing a corrective action plan within the two months that follow. As this process evolves, we will keep you informed.

A second review was held Friday and Saturday of last week. This was the meeting of the SLAC Policy Committee (SPC). The SPC is the highest level oversight committee for SLAC. The group meets twice yearly and reports to the University. At this meeting, the SPC considered a range of topics that included LCLS Construction and loss of the CLOC building, plans for accommodating the space needs resulting from the loss of the CLOC, and programmatic topics for photon science (PS) and particle and particle astrophysics (PPA). They heard reports on progress in developing a strategy for scientific computing and accelerator science. The ES&H program was also discussed. The PPA faculty presented their 5-year faculty development plan.

Delays on Loop Road

Short traffic delays along Loop Road will be necessary this week to allow road crews to install a new sidewalk. Parking Lot D will be closed for the duration of the project, and one lane of Loop Road will be intermittently blocked between the Guest House and Building 50. Please use caution and obey construction crew instructions. Read access notice...

Holiday Giving Campaigns

The SLAC Community is once again showing its generosity by participating in the Second Harvest Food Drive, the SLAC Blanket & Coat Drive and the Family Giving Tree.

The Second Harvest campaign provides food for people in need from Gilroy to South San Francisco and from the Coast to the Bay. Last year 30 million pounds of food were distributed to needy families with children, senior citizens and over 750 partner agencies and distribution sites. Look for notices on barrels or bags throughout the SLAC site to see what foods are most needed.

Our Coats and Blankets will be once again be picked up by a local mission who takes them to the streets of San Jose and distributes them via a local shelter to the needy and homeless. With this drive, items are given directly to the people who need them most.

For a list of food barrel and blanket box locations, check out the website.

Don't forget to pick up a Wish Card from the Family Giving Tree and bring a gift to a child who would otherwise go without. Gifts should range between $20 and $30 to ensure equality among all recipient households. Wish Cards can be found at a number of locations listed on the giving campaign website.

The Family Giving Tree campaign will end December 12—the Food Drive and Coat & Blanket Drive will end December 15.

We look forward to another successful year watching our wonderful SLAC family step up to help those less fortunate.

Thanks for giving!

Safety Firsts

Have you ever made a mistake, almost had an injury or accident, and then told yourself how lucky you were? In the recent crash of the Air Force's largest plane, the C-5A, the experienced flight crew made three separate serious errors—wrong flap setting, wrong throttle settings, wrong altitude—and then a fourth which brought down the plane. I'll mention the relevance to us tomorrow.

Events (see all | submit)

Access (see all)

(see all | submit)

 Lab Announcements

Community Bulletin Board

News (see all | submit)

dividing line
(Office of Science/U.S. DOE Logo)

View online at