THE ELECTRONIC ALADDIN NEWSLETTER NO. 30

November 2001 / March 2002

1. APRIL 7TH OPEN HOUSE WAS VERY SUCCESSFUL

Our yearly Open House event continues to be very popular with the public. Visitors enjoyed themselves learning about our research and participating in demonstrations and activities. Over 100 of the 249 people attending the Open House were children. During the 12:00 to 4:00 PM event we led 22 tours of our facility. About 50% of the participants filled out our feedback form in which many indicated how impressed they were with what they saw and also thanked Staff and Users for their effort to reach out to the public.

This year our tour consisted of two introductory talks, three stops around the ring, and a final stop at an "experts table." The two talks introduced the public to synchrotron light, how we make it, and how we use it (Mary Severson and Ken Jacobs). The three stops included presentations on: 1) materials science and how it has affected the development of magnetic storage devices (Cliff Olson), 2) studying metal halide lamps to understand how they work (Geoff Bonvallet and Dave Smith), and 3) using spectromicroscopy techniques to study 4.4 billion year old zircon rocks to determine Earth's early environment (Brad Frazer). At the "experts" table, visitors were given a chance to ask more questions and give feedback on the event (Roger Hansen).


2. BREAKING OF TIME REVERSAL SYMMETRY IN HITC MATERIALS

Time reversal is one of the fundamental symmetry operations in nature. Adam Kaminski at the University of Illinois Chicago and a large team of collaborators undertook a difficult experiment at the SRC to test whether this symmetry is broken in high temperature superconductors. They used circularly polarized light combined with angle-resolved photoemission to search for the subtle effects of symmetry breaking. It took several months of preparation and data acquisition to eliminate the many possible sources of systematic errors. The results in cond-mat/0203133 (Nature, April 11) demonstrate that time reversal symmetry is indeed broken, but only in the pseudo-gap state of under-doped samples. Such a specific finding places strong constraints on theories of superconductivity.


3. LOW EMITTANCE OPERATIONAL

As the next step in making lowered emittance fully operational, a tuning of the Aladdin storage ring with a horizontal emittance one third of the standard configuration is now being offered regularly on Wednesday morning shifts. The horizontal beam size measured in the optical diagnostic stations is about one third that of the standard configuration. The average vertical beam size and the beam-current lifetime product are about 10 % smaller than nominal. Beam position variations from the normal mode appear to be small enough to be operationally transparent to the beamlines and experiments. Studies by the Accelerator Development and Operations Groups are continuing during Development Periods to further improve the electron beam optics, lifetime, and overall performance of low emittance tunings. Some of this work is being carried out by physics graduate student Ryan Miller as part of his degree program.
These Wednesday morning shifts are intended to provide Users and staff a setting to explore together the opportunities offered by lower emittance operation of Aladdin. In a recent run, Pupa De Stasio and Brad Frazer acquired images of zircons with the SPHINX spectromicroscope on the 6 m TGM 062 with the low emittance LF15 tuning and immediately after re-injection, with the regular 800 MeV beam. All acquisition parameters were identical; therefore, the only variation was due to the beam emittance. They detected a 65% increase in the flux density with LF15, compared to regular beam, after normalization to the beam current.


4. SCIENTA 200 REFURBISHED

After a two quantum refurbishing period in December and January, the Scienta 200 analyzer is back in operation!
In response to User feedback concerning the performance of the workhorse SES 200 analyzer, an extended maintenance was undertaken to address the issues of vacuum and sample lifetime, electronics and calibration, and operational policies and procedures.
Here is a brief summary of the successful refurbishment process:
1) Additional pumping in the form of a cryopump near the measurement area and an ion pump near the hemisphere has resulted in a factor of three decrease in the base pressure to 3 x 10-11 torr and a commensurate increase in sample lifetime,
2) The Scienta power supplies were all recalibrated resulting in an energy repeatability of <1meV,
3) A User manual containing new policies and procedures for use of the instrument has been generated which should aid in maintaining the SES 200 in its pristine condition.
The analyzer completed two successful quanta on the 081 NIM, causing one user to comment: "This is the best condition the Scienta has been in since I have used it." It is currently installed on the PGM where it will remain until the end of the first half of 2002 schedule.


5. SCIENTA 2002 UPDATE

SRC's second Scienta system for Users, the SES 2002, is getting close for a first test run. Currently, the shop is working on parts for the sample cryostat which should be ready for assembly within the next two weeks. The system will then be moved to the 4m undulator NIM beam line for first test measurements. If the system performance is up to specifications and the vacuum conditions meet User requirements, the analyzer will be scheduled as a User instrument and should be available during the second half of the 2002 beam time period.


6. CONGRATULATIONS TO SRC RESEARCHERS

James W. Allen, a long-time SRC user from the University of Michigan, received the 2002 Frank Isakson Prize of the American Physical Society (APS). The prize recognizes Jim "for his outstanding contributions to the field of spectroscopy in strongly correlated electron systems leading to elucidation of many-body physics." Details of his work can be found at: http://www.aps.org/praw/isakson/02allen.html

Victor Aristov at the Commisariat a l'Energie Atomique (CEA) in Saclay, France, has been awarded the 2001 Russian National Prize in Science and Technology ("Poutine Prize"), together with Alferov (2000 Nobel prize winner) and Lifshitz (the one of Landau and Lifshitz). He received the honor for his work on "Electronic and Atomic Processes at Solid Surfaces", in particular for semiconductor surfaces investigated by STM and synchrotron radiation. He worked at the SRC for 5 months in 1994 with Patrick Soukiassian (then at Northern Illinois University) and published seminal papers on the formation of semiconductor interfaces.

Art Ellis, SRC user and professor of chemistry at the UW-Madison, was honored by the NSF Distinguished Teaching Scholar Award, based on his contributions to research and to undergraduate education. His research at the SRC has been on photoemission studies of chemical surface passivation of GaN, with plans to add infrared spectroscopy as additional diagnostic tool. He is engaged in a variety of educational and outreach activities at the Madison MRSEC on Nanostructured Materials and has helped the SRC getting started with such activities.

Esther Olson is one of the two recipients of the 2002 Wisconsin Alumni Association Award for Excellence in Leadership. Her contributions as Assistant Director of the SRC and the Physical Sciences Laboratory (PSL) were acknowledged. "She has the ability to marshal the people, capital, and intellectual resources of the university ... and does that "with civility,
passion, and energy" said Henry Cuthbert, Senior University Legal Counsel.

James W. Taylor, former director of the SRC and professor emeritus at the UW-Madison, has been selected as the winner of the J. Calvin Giddings Award for Excellence in Education by the American Chemical Society. He was chosen because of his remarkable success in training PhD students, his development of graduate and undergraduate instrumental analysis, his role in creating the University of Wisconsin's teaching Academy, and many other educational activities.

The following current and former Users of the SRC were recently elected fellows of the American Physical Society (APS):

Paul Canfield (Ames Laboratory) for crystal growth and characterization of novel materials such as heavy fermion compounds, magnetic superconductors and quasicrystals, leading to important advanced in condensed matter and materials physics.

Juan-Carlos Campuzano (University Illinois Chicago) for fundamental contributions to the physics of high temperature cuprate superconductors by use of angle resolved photoemission spectroscopy.

Franco Cerrina (Center for Nanotechnology and Dept. of Electrical and Computer Engineering, UW-Madison), for innovative physics applications in the domains of lithography, x-ray optics and microscopy.

Alfonso Franciosi (Instituto Nazionale di Fisica della Materia) for his contribution to the understanding of the properties of interfaces, including semiconductor heterojunctions and metal/semiconductor contacts, and his efforts to bridge the gap between basic interface science and applications.

Boyd Veal (Argonne National Laboratory) for significant contributions to photoemission studies of transition and actinide metal compounds and for seminal studies and innovations within the YBCO family of cuprate high-temperature superconductors.

Congratulations to all!