ALSNews is a biweekly electronic newsletter to keep users and other interested parties informed about developments at the Advanced Light Source, a national user facility located at Lawrence Berkeley National Laboratory, University of California. To be placed on the mailing list, send your name and complete internet address to ALSNews@lbl.gov. We welcome suggestions for topics and content.

Previous Issues are available.


ALSNews           Vol. 66           November 26, 1996

Table of Contents


    1. OPERATIONS UPDATE
    2. NEW LENDING LIBRARY FOR ALS VIEWGRAPHS
    3. THANKSGIVING IS COMING

1. OPERATIONS UPDATE
(contact: rmmiller@lbl.gov)

Beam availability for the last two weeks was 89.7% overall and 90.3% for user shifts. Causes of lost beam time included network hardware problems repaired on Sunday, November 24, and difficulty in filling the scheduled bunch pattern. (This pattern consists of 304 normally-filled bunches and one high-current bunch.)

Operations Summary for November 26 - January 6

Nov 26, 00:00- Nov 27, 23:15  1.9-GeV/300-mA/304-bunch user operations,
                                with one bunch filled to 20 mA
Nov 28, 00:00- Dec 02, 07:30  Thanksgiving holiday wknd, no operations
Dec 02, 07:30-24:00           Maintenance and startup
Dec 03, 00:00-24:00           Accelerator physics
Dec 04, 00:00-08:00           User scrubbing and special operations
Dec 04, 08:00- Dec 09, 07:15  1.9-GeV/300-mA/304-bunch user operations
Dec 09, 07:30-24:00           Maintenance & startup
Dec 10, 00:00-24:00           Accelerator physics
Dec 11, 00:00-08:00           User scrubbing and special operations
Dec 11, 08:00- Dec 16, 07:15  1.5-GeV/400-mA/304-bunch user operations
Dec 16, 07:30-24:00           Maintenance & startup
Dec 17, 00:00-24:00           Accelerator physics
Dec 18, 00:00-08:00           User scrubbing & special operations
Dec 18, 08:00- Dec 23, 23:15  1.5-GeV/400-mA/304-bunch user operations
Dec 24, 00:00- Jan 06, 07:30  No operations - holidays

2. NEW LENDING LIBRARY FOR ALS VIEWGRAPHS

The ALS now has a collection of viewgraphs for use by users and staff for presentations. Using the set of binders located in Ronnie Nelson's Office (Building 80, Room 242, ext. 6875), one can quickly peruse the collection and select the viewgraphs most appropriate for a given talk. One then orders viewgraphs by filling out a short viewgraph request form and submitting it to Ronnie. Please allow 5 days if possible.

The collection is divided into three main categories:
- General: General information on the ALS facility and beamlines, 
  synchrotron radiation and its properties, bend magnets and 
  undulators, photographs of beamlines and the machine, general 
  schematics of beamlines and techniques, etc.
- New Science: Scientific results taken at the ALS by users, arranged 
  by beamline.
- Outreach and Education: Materials created for our teacher workshop 
  and outreach activities.

In addition, users registering at the ALS User Office will now receive a coupon that can be redeemed at Ronnie's for a starter collection of our most popular viewgraphs, useful in presentations that include a general overview of the ALS.

3. THANKSGIVING IS COMING

...And we've kept this issue of ALSNews short and sent it early to interfere less with the efforts of those who celebrate this holiday to get away for the weekend! But for those of you who would like a taste of ALS Thanksgiving humor, we are re-running the following recipe, first seen two years ago in ALSNews. Bon appetit!

Baked VV a` la ALS

Ingredients:
    1 steel or aluminum vacuum vessel (VV) (preferably one with undesired
water and hydrocarbon impurities)
    Lots of aluminum foil
    Electric heating tapes and vacuum pumps as needed, depending on size and
shape of VV

Directions:
1) "Dress" the VV:
    - Wrap in a tight layer of aluminum foil (optional)
    - Wrap with electric heating tapes
    - Cover with more foil**

2) Activate vacuum pumps to whisk away impurities as they are driven from the
inner walls during baking. Be sure to attach a residual gas analyzer to
identify and measure the impurities!

3) Bake for 5-10 days, allowing a day at the beginning to bring the VV up to
its maximum temperature and a day at the end for slow cooling, during which
you may need to re-torque the vacuum seals to prevent loss of vacuum and
re-contamination.
Note: When baking steel VVs, it is often desirable to start with  a "hard
bake" at 200 degrees Celsius to drive off hydrocarbons such as oils from
fingerprints or residuals from the precleaning process. Then, after more
delicate optics (stuffing!) have been installed and aligned, a "soft bake" at
about 125 degrees Celsius eliminates remaining moisture and gases (sorry, no
basting). 

4) When done, the VV's residual pressure should be on the order of  10**-10
torr. Use as desired!

Serves: Many users

** The first layer of foil, depending on which cook you consult, is to
distribute the heat evenly (since aluminum is a much better thermal conductor
than stainless steel) and/or to prevent oxidation of the steel surfaces due
to direct contact with the heating tapes. The outer layer of foil serves
mainly to insulate the equipment by reflecting infrared (heat) radiation back
in toward the VV being baked.