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.

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ALSNews           Vol. 40           November 15, 1995

Table of Contents


    1. OPERATIONS UPDATE
    2. INNOVATIONS CONTRIBUTE TO SPEEDY STORAGE RING ALIGNMENT
    3. LAB OPEN HOUSE A BIG SUCCESS
    4. LONG-TERM SCHEDULE EXTENDED THROUGH APRIL
    5. CALL FOR INDEPENDENT INVESTIGATOR PROPOSALS

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

The ALS will be running with the longitudinal feedback system off during all user shifts November 12-22, because running with feedback at a current greater than about 250 mA results in unacceptable heating of the ceramic tubes in the injection straight. The ALS will be contacting PRT spokespersons to find out whether they prefer running at 400 mA without feedback or at a reduced current with feedback during future operations until the problem can be solved. This applies to both 1.5 and 1.9 GeV operation.

Operations Summary for November 15 - December 4

Nov 15, 00:00-08:00           Scrubbing & Tests
Nov 15, 08:00- Nov 22, 24:00  1.5-GeV/400-mA/320-bunch user operations
Nov 23, 00:00- Nov 27, 08:00  Thanksgiving holiday/no operation
Nov 27, 08:00-24:00           Maintenance & Startup
Nov 28, 00:00-24:00           Accelerator Physics
Nov 29, 00:00-08:00           Scrubbing & Tests
Nov 29, 08:00- Dec 04, 08:00  1.9-GeV/260-mA/320-bunch user operations
Dec 04, 08:00-24:00           Maintenance & Startup

2. INNOVATIONS CONTRIBUTE TO SPEEDY STORAGE RING ALIGNMENT
(contact: gwthur@lbl.gov or richard_demarco@macmail.lbl.gov)

Survey and alignment of the ALS storage ring was one of the primary tasks in the September-October shutdown. Gradual settling of the ALS floor means that every year or two, the girders holding the storage ring magnets need to be checked and re-aligned. Plans for the shutdown called for surveying nearly all the magnets in the ring and then aligning as many girders as possible, with five girders programmed as a reasonable estimate. However, improvements designed to streamline the alignment procedure helped save enough time so that all twelve girders could be aligned within the shutdown schedule.

First, the survey and alignment crew used new, specialized systems designed by Ken Rex of the ALS Mechanical Engineering Group for installing digital indicators used in alignment. The realignment process requires measuring and adjusting the position of key points on the girders while monitoring the position of the bellows which join vacuum-chamber sections in the ring. Careful monitoring and control of the bellows' position are required to minimize shearing distortions on the bellows as each vacuum chamber segment moves relative to its neighbors during girder realignment. Rex developed two improved installation hardware systems for installing the indicators: one allows the indicators above the key girder points to be mounted easily on the ceiling blocks above the girders, eliminating the cumbersome support structures formerly required, and the other is a standardized, interchangeable bracket system used to support the array of indicators needed to monitor bellows movement. These innovations saved considerabl e work and time for the survey crew.

An additional improvement helped speed the process of aligning each girder on its six-strut supports. These supports are generally straightforward to use, since on most structures the struts governing vertical movement and two directions of horizontal movement are all at right angles (so only one set of struts affects each possible movement or rotation). On the storage ring girders, however, one set of horizontal struts is placed at a 45-degree angle to the floor to provide greater seismic stability, so adjustment of these struts affects the vertical position of the girder and complicates girder realignment. James Osborn of LBNL's B-Factory Project eased this task by creating a spreadsheet to convert the desired girder-position correction into the number of turns required on each strut to achieve that correction. Adjustments based on this spreadsheet accomplished about 90% of the necessary girder movements and were followed by fine-tuning based on the digital indicators.

The dedicated work of the ALS Survey and Alignment Group, aided by these time-saving advances, yielded a ring alignment well within 150-micron tolerances. Of the 12 girders, 10 have been surveyed to confirm alignment so far, and the average alignment error is only 60 microns (less than the thickness of a human hair).

3. LAB OPEN HOUSE A BIG SUCCESS

The Lab-wide Open House held on Saturday, October 28 was met with overwhelming enthusiasm by Lab and community members alike. Nearly 5,000 visitors took advantage of this special opportunity to gain a first-hand look at the wide range of scientific activities going on around the Lab.

The theme at the ALS was "light" and the fun of science and engineering. Young and old alike had a chance to participate actively in demonstrations and hands-on exhibits ranging from "Can You Make An Electron Move the Way the ALS Does?" to the "Electronics Petting Zoo" where children were encouraged to take apart meters, computer drives, and more to see how they work. To set a festive atmosphere and entertain in an informative way, the outside patio featured Cool Science demonstrations using liquid nitrogen, Soapy Science with giant soap bubbles to illustrate interference effects, and the Electron Adventure where young children experienced the life of an electron at the ALS.

Inside the ALS, exhibits and hands-on activities were arranged as part of a thematic tour around the experiment floor. Nearly 100 volunteers including outside users and staff from the ALS and Center for X-Ray Optics were on hand to answer questions and help with the demonstrations. The ALS especially wants to thank the many users who actively participated by creating their own interactive displays and beamline posters.

Everyone seemed to enjoy the sense of humor used in the exhibits, as it helped show that science is fun and accessible to all. For example, one popular poster that greeted visitors as the entered the ALS was:

"A Day in the Life of an ALS Electron" -- Compare your average day to that of an electron--you may begin your day with a blast of caffeine; the electron's begins with a blast from an electron gun which propels it down a linear accelerator. As you drive along the freeway at a comfortable 55 mph on your way to work, the electron is already traveling at more than 186,000 miles per second--just barely under the "speed limit" for light. While a donut may be sufficient for your mid-morning energy boost, the electron receives over a million successive "kicks" to increase its energy. As you plow through your daily workload, the electron speeds around the storage ring over a million times per second, emitting light at each bend in its path. By the time you break for lunch, the electron's day is just about over--it has been blasted, boosted, and bounced around--all to produce illuminating light for scientific experiments--and traveled more than 2 billion miles in the process. So, when you think you've had a long, roug h day--remember the electron's!

The ALS also developed a poster called "Inside the ALS" as a take-home souvenir and a resource for science teachers. It shows how the ALS works using cartoons, key concepts, diagrams, and photos and is designed to be accessible to students at all levels. Anyone who would like to receive a poster in the mail should send their complete mailing address to ALSNews@lbl.gov with "Send Poster" in the subject line.

4. LONG-TERM SCHEDULE EXTENDED THROUGH APRIL
(contact: fred_schlachter@lbl.gov)

The long-term operations schedule for the ALS has now been determined through April 1996. The table below (best viewed in a monospaced font) gives the schedule for February through April, 1996; the schedule up to February appeared in ALSNews Vol. 36, 9/19/95. (You can receive a copy of Vol. 36 automatically by sending email to alsnews@lbl.gov with the subject line "send ALSNews 36".)

The first part of each heading is the storage ring energy in GeV; the MB stands for multi-bunch (there is no two-bunch operation scheduled between February and April). Accelerator physics time, maintenance/startup, and holidays occupy the time not accounted for in the "Dates" column, as well as some shifts on the first and last days of most periods listed.

Dates (MM/DD/YY)    1.5/MB    1.9/MB    Installation Shutdown

01/31/96-02/05/96             1.9/MB
02/07/96-02/12/96   1.5/MB
02/14/96-02/18/96   1.5/MB
02/21/96-02/26/96   1.5/MB
02/28/96-03/04/96             1.9/MB
03/06/96-03/11/96   1.5/MB
03/13/96-03/18/96   1.5/MB
03/20/96-03/25/96             1.9/MB
03/27/96-04/01/96   1.5/MB
04/03/96-04/08/96             1.9/MB
04/10/96-04/15/96   1.5/MB
04/15/96                                Shutdown begins

5. CALL FOR INDEPENDENT INVESTIGATOR PROPOSALS

The ALS has two cycles per year for soliciting proposals from scientists who wish to conduct research at the facility as independent investigators: April-September and October-March. The next submission deadline is December 1, 1995, for beamtime between April 1996 and September 1996.

To request a proposal form, contact:
Elizabeth Saucier, ALS User Administrator
Tel: (510) 486-6166
Fax: (510) 486-4960
Email: alsuser@lbl.gov

For beamline and PRT information, contact:
Fred Schlachter, ALS Scientific Outreach
Tel: (510) 486-4892
Fax: (510) 486-6499
Email: fred_schlachter@lbl.gov