ELECTRONIC ALADDIN NEWSLETTER NO. 16
January / February 1997
ROGER OTTE REMEMBERED
Roger Otte passed away on December 11, 1997, after a long struggle with
multiple myeloma. He was long-time operations manager at the Tantalus storage ring and at
Aladdin, until his retirement in 1995. To many students, postdocs, and visitors at
Tantalus and Aladdin he was like a father, introducing them to the world of synchrotron
radiation and to life around it. He will be remembered by many of us who have me\made
synchrotron radiation their career. Here are a few reminiscences from colleagues:
"More than anyone else, Roger was responsible for making SRC 'user
friendly' for young scientists."
"Roger was always a gentleman (and a gentle man). I never saw him
show any frustration-even when things were not going well."
"During the battle for the survival of Aladdin, Roger was in
charge of many things and in particular of completing the shielding. Unfortunately, he
suffered a heart attack which put him out of business for a while. This emphasized how
much work Roger was doing for the success of the project, and how extremely difficult
would have been to replace him. In fact, he was not fully replaced: we had to patch up
things but could not match the quality and quantity of his contributions. On the other
hand, the health crisis also emphasized Roger's dedication to the project and to his work
in general. It was very difficult to keep him quiet for the minimum time required by his
situation, and he was back to the front line as soon as he could. I remember how touched
we all were by what Roger did: it was a great boost to the morale."
NEW UNDULATOR BEAM LINE BEING INSTALLED
Coordinated by Greg Rogers, a new undulator beam line for high
resolution valence photoemission is taking shape. It consists of an electromagnetic
undulator and a high-resolution normal incidence monochromator. This project is a joint,
NSF-funded effort involving SRC and several users with Juan Carlos Campuzano (University
of Illinois-Chicago) as Principal Investigator.
The SRC undulator was transported from PSL to SRC in late January. In
situ personnel radiation shielding of the device has been completed. At the present time
surveying and alignment, connections of electrical power and cooling, and integration of
control circuitry and software are in progress. During March the machine trials are
The PRT-SRC 4m NIM beamline is nearing completion. It will have an
energy range from 6 to 50 eV with a resolving power up to 3 x 10^4, and throughput up to 3
x 10^11 photons/sec. The grating chamber and slits are currently under testing at
McPherson Inc., and are scheduled for delivery in early April '98. Most other components
are finished and in position at the SRC, including two beam position monitors which will
be used to document the undulator light in the next several weeks. Testing of the beamline
will begin in July, and it will be turned over to users in September of '98.
QUADRUPLE COINCIDENCES AT THE DCM
For a complete photochemistry experiment, one would like to detect all
the products that a photon creates after being absorbed by a molecule, such as
photoelectrons, ions, and molecular fragments. The more of these fragments that can be
detected in coincidence, the closer one gets to the ideal experiment.
Adam Hitchcock and coworkers at McMaster University have pushed the
field to quadruple coincidences, detecting coincidences between a photoelectron and the
three photoions of the carbon-oxygen-sulfur molecule following S 1s core excitation at
2472 eV. For atomic physicists, this is comparable to a quadruple jump at the Winter
Olympics. This work is aimed at breaking bonds selectively by excitations from core levels
of specific atoms in a molecule.
MAGNETIC LINEAR DICHROISM
For determining the magnetization in thin films element-by-element,
magnetic circular dichroism (MCD) bas become the technique of choice in recent years.
Markus Schwickert and G. R. Harp (Ohio University) demonstrated magnetic linear dichroism
(MLD) in Co, Fe, Cr, and V thin films. The success of this experiment is owed to the very
high stability of the flux on the HERMON beamline at the SRC, which allowed measurements
of differences smaller than 0.0004 of the absorption signal. The MLD effect scales
approximately as the magnetization squared, in agreement with theory, which makes
antiferromagnetic samples accessible that cannot be probed by MCD.
COMPUTER HELP DESK ESTABLISHED
A help desk has been established at the SRC to assist with computing
and data conversion. It can be reached at 2306 or email@example.com. The desk is being
staffed by Isaac Pentimaki.
HONORS FOR SRC RESEARCHER
Mike Bancroft, University of Western Ontario chemistry professor, has
won the Morley Award from the American Chemical Society. On May 27, 1998, Prof. Bancroft
will receive the award, the highest award given by the Cleveland section of the society. A
symposium involving his work photoelectron and Mössbauer spectroscopies in inorganic
chemistry and geochemistry will be held the same weekend. The award, which recognizes
significant contributions to chemistry made by someone within 250 miles of Cleveland, is
named for the late pioneering chemist Edward Morley, the founding chairman of the
Cleveland Section who made significant contributions to science. The award consists of
$2000 and a gold medallion.