Three researchers who have achieved international acclaim for their
accomplishments in designing unusual detector systems have been
promoted to the rare Distinguished Scientist classification at Berkeley
Lab.
David Nygren in the Physics Division and Arthur Poskanzer and Frank
Stephens in the Nuclear Science Division were named by Laboratory
Director Charles Shank to receive the prestigious "Distinguished"
title, which is currently shared by just three others at the Lab.
In his appointment letters, Shank noted that the Distinguished
Scientist rank is "reserved for the most exceptional senior scientists.
It is expected that the Laboratory will have only a few such stars at
any given time."
The Distinguished Staff Scientist/Engineer level is reserved for those
who "have a sustained history of distinguished scientific and technical
achievements and/or have directly contributed to the Laboratory's
preeminence," according to the Lab Regulations and Procedures Manual.
The incumbents are "seen as nationally or internationally recognized
authorities and leaders in their field; their expertise is sought after
by professional colleagues."
Nygren, 57, was nominated by Physics Division Director Robert Cahn, who
cited his invention of the Time Projection Chamber (TPC), which has had
a profound effect on both particle and nuclear physics, and his
pioneering work on pixel detectors. Cahn also cited his innovative
design for an x-ray imaging device based on silicon detectors and
high-speed data acquisition, and his current work in very-large-scale
neutrino detectors.
"The TPC opened new opportunities for experimentation across a broad
range of particle and nuclear physics," Cahn said. "The purity and
power of his proposal are why, more than 20 years later, new TPCs are
still being built."
Nygren, who has been called the most distinguished developer of
particle detection instruments in the country, has been with Berkeley
Lab since 1973 and is a previous winner of the prestigious E. O.
Lawrence Award.
Poskanzer, 64, nominated by former Nuclear Science Division Director
James Symons, has been influential as the head of the Relativistic
Heavy Ion Program. Symons credited Poskanzer's leadership in uniting
the diverse elements of the Relativistic Nuclear Collisions program
into a dominant group, within which the STAR detector has been
developed as "one of the principal reasons that DOE has maintained a
significant nuclear physics presence" at the Laboratory.
A scientist at Berkeley Lab since 1966, Poskanzer is considered a
pioneer in the use of high energy reactions to produce nuclei far from
stability, especially in the low-Z region. He is the co-discoverer of
28 isotopes. In the field of relativistic heavy ion reactions, he has
led a group effort pioneering in the experimental study of central
collisions. Poskanzer was co-leader of the Plastic Ball project, which
discovered the collective flow of nuclear matter. He is spending this
year at CERN in Switzerland, studying nuclear collisions in a new
energy domain in search of the predicted Quark-Gluon Plasma.
Now in his 41st year at Berkeley Lab, Stephens, 64, is the originator
and spiritual leader of the Gammasphere project, the gamma-ray detector
that was officially dedicated on Dec. 1. "His vision has moved the
nuclear structure community into the technical big-time, and his
detector provides the principal justification for continued operation
of the 88-Inch Cyclotron," Symons said in his nomination.
Stephens is one of the foremost authorities on the structure of nuclei
and the relationship of that structure to phenomena in other branches
of physics. Utilizing heavy-ion beams from the 88-Inch Cyclotron, he
has explored the collective properties in nuclei, high angular momentum
phenomena, giant resonances, and nuclear reaction mechanisms for which
he was awarded the Bonner Prize by the American Physical Society in
1980.
Division nominations were reviewed by the 12-member Laboratory Staff
Committee, which forwarded recommendations to Shank for appointment.
Physicist George Gidal, chair of the committee, said the honorees share
the qualities of "long and sustained work in a particular discipline,
national and international recognition, and a single-minded dedication
to pushing their field to new heights. And they are innovative,
constantly seeking new techniques that often lead to whole new fields
of science."
Gidal said the "Distinguished" class is intentionally limited to a
small percentage of the approximately 130 senior scientists at the Lab.
Other Berkeley Lab staff members who have achieved "Distinguished"
career status include former Laboratory directors Andrew Sessler and
David Shirley, and retired engineer Frederick Goulding.