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. 33           August 8, 1995

Table of Contents


    1. OPERATIONS UPDATE
    2. STORAGE RING STATUS HOTLINE NOW OPERATING
    3. FEEDBACK TESTS SUCCESSFUL -- INCREASED BRIGHTNESS AVAILABLE
    4. COLLABORATIVE RESEARCH AGREEMENT SIGNED WITH INTEL
    5. NEW REVISION OF USERS' HANDBOOK AVAILABLE

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

Beam availability for the last two weeks was 90.6% overall and 87.1% during user shifts. Causes of lost beamtime included a loose storage ring vacuum-chamber-protection thermocouple connection, a plugged orifice on the storage ring sector 5 water flow interlock, and four storage ring quadrupole power supply failures in sectors 4, 7, and 12.

Operations summary for August 8 - August 27
1.5-GeV, 400-mA, 320-bunch operations for users:
    August 9, 08:00-16:00
    August 10-13, 08:00-23:15
    August 16, 08:00-16:00
    August 17-20, 08:00-23:15
1.5-GeV, 2-bunch operations for users:
    August 23, 08:00-16:00
    August 24-27, 08:00-23:15
Accelerator Physics:
    August 8, 15 & 22, 08:00-23:15
    August 9, 16 & 23, 16:00-23:15
Maintenance:
    August 14 & 21, 08:00-16:00, with startup 16:00-23:15

Weekly scheduling meeting: Fridays, 3:30 p.m. in the Building 6 conference room.

2. STORAGE RING STATUS HOTLINE NOW OPERATING
(contact: rmmiller@lbl.gov)

A new hotline begins service today, allowing users to check ALS storage ring status without calling the control room. By dialing (510) 486-6766 (or ext. 6766 from LBNL phones), callers can obtain the current ring status including energy, fill pattern, time of last fill, next planned fill, and updates when beam is down.

3. FEEDBACK TESTS SUCCESSFUL -- INCREASED BRIGHTNESS AVAILABLE
(contact: ajackson@lbl.gov)

The first tests of the full multibunch feedback system (both longitudinal and transverse), capable of controlling 324 out of the possible 328 bunches in the ALS, were successfully concluded last week (July 25 and 26). These and tests carried out the following week indicate that the ALS can operate with far brighter beams than those advertised in the ALS Handbook (Pub-643 Rev. 2). Electron beam sizes measured on beamline 3.1 indicate beam emittances of 5.1 nm-rad (horizontal) x 0.06 nm-rad (vertical), with a relative energy spread of 0.0008. These numbers should be compared with the numbers used to calculate brightness in the handbook: 10 nm-rad x 1 nm-rad with the same energy spread -- note the 16-fold change in vertical beam emittance, a result of the excellent beam alignment in both transverse planes. One consequence of this highly condensed bunch is that the beam lifetime, which is dominated by internal scattering of electrons in the bunches (the so-called Touschek effect), is only 1 hour at 400 mA. Although operation in this mode provides maximum brightness, some users will prefer lower brightness and longer lifetime.

Our investigations to date have shown that the only way to increase the lifetime is to move the betatron operating point towards the coupling resonance, the same trick we use to increase lifetime during two-bunch operation. This gives a lifetime of up to 4 hours (at 400 mA) with a proportional increase in the vertical beam emittance. We would like to offer running in this mode to users. The brightness will be higher than at present, and the lifetime shorter than at present. We propose operation with an initial lifetime (at 400 mA) of approximately 4 hours during the standard multi-bunch, 1.5-GeV operating period August 16-20. A memo has been sent to all users scheduled to run experiments during this period to solicit their input on the proposed change.

4. COLLABORATIVE RESEARCH AGREEMENT SIGNED WITH INTEL
(contact: glen_dahlbacka@macmail.lbl.gov)

A new two-year collaborative research agreement involving Intel, the ALS, and LBNL's Center for X-Ray Optics will address some of the technological challenges faced by the semiconductor industry in their continuing pursuit of advancing the state of the art in integrated circuit performance. The research will focus on two areas identified as major "industry-wide" concerns by the Semiconductor Industry Association: improved methods for silicon wafer surface materials analysis, and new fabrication techniques which will allow the minimum feature size on integrated circuits to be reduced from the present level (approximately 0.35 microns) to 0.10 microns.

The funding for the Cooperative Research and Development Agreement (CRADA) includes $100K from DOE's Energy Research-Laboratory Technology Transfer program, $115K in programmatic funding from the ALS, and $531K from Intel. One of the key techniques to be developed is soft x-ray spectromicroscopy, the combination of the traditional macro-techniques of x-ray absorption near-edge structure (XANES) and x-ray photoelectron spectroscopy (XPS) with microscopy. These techniques have applications not only to semiconductor problems, but also to studying other complex materials. Thus, LBNL's general materials research capabilities will benefit from the CRADA.

As the minimum feature size of integrated circuits shrinks, the measurement of local chemical information becomes more critical, but also more difficult. Measurement efforts will focus on two situations common to semiconductor manufacture with shrinking feature sizes: 1) where a defect (such as a contaminant particle) has occurred and chemical information is required in order to localize the defect's origin in the fabrication process, and 2) where a material used in fabrication alters its behavior when localized in ever smaller areas. In each of these cases, traditional laboratory instrumentation is becoming increasingly limited, but the new capabilities and techniques of spectromicroscopy may provide a way forward.

One contender in the pursuit to further shrink the size of circuit features and the spaces between them is extreme ultraviolet (EUV) lithography. The development of EUV lithography depends on developing optical surfaces with contour and roughness considerably better than what is available today, and coatings with high reflectivity at shorter (EUV) wavelengths. This requires new test procedures (interferometry) with improved accuracy (smaller wavefront error), operating at the wavelength at which the coatings are intended to be used. LBNL's Center for X-Ray Optics will use CRADA funds to fabricate a monochromator for Beamline 12.0 at the ALS. An EUV interferometry endstation on this beamline will be used to test the surface figure (e.g., shape) of multilayer coated optics and optical systems, crucial elements in the EUV lithography process. Information gleaned from this research will enhance CXRO's optics program as well as Intel's future lithography plans.

5. NEW REVISION OF USERS' HANDBOOK AVAILABLE
(contact: alsuser@lbl.gov)

What to do before you come to the ALS? Whom to contact? How to get here? Where are the vending machines for midnight snacks? These are just a few of the topics covered in the new revision of the ALS Users' Handbook. The handbook is designed to be a comprehensive guide to what users want or need to know before and during their stay at the ALS.

Copies of the handbook will be sent to all current users, and to people who requested copies using the insert from the May 1995 ALS Newsletter. If you would like a copy and these lists do not include you, please send your complete mailing address to the ALS User Office (email: alsuser@lbl.gov; Fax: 510-486-4773). Be sure to include "please send Users' Handbook" in your message.