Larry Wai and Anna Gosline
The Large Area Telescope (LAT) project, a key component of GLAST,
recently sailed through its first phase of testing with great success.
Conducted at SLAC in conjunction with NASA, this milestone brings
physicists one step closer to uncovering the mysteries of the gamma ray
sky. The project is an exciting new horizon for particle physics that
could lead to discoveries of cosmic proportions.
Clean room where the LAT team tested the integrated
detector with cosmic ray muons as well as gamma rays.
(Photo by Peter Ginter)
"The LAT detector will be the world’s most sensitive and massive
space-based gamma ray telescope when it is launched in 2006," said LAT
principal investigator Peter Michelson (Stanford University).
The energy range of the LAT will be unparalleled—from 10 MeV to over
100 GeV—and much more sensitive at detecting and deciphering high energy
gamma rays than any other instrument in space. This superior range and
sensitivity will allow scientists to answer previously unimaginable
"GLAST science topics include study of the most powerful accelerators
in the universe, active galactic nuclei, as well as the potential
discovery of the elusive nature of Dark Matter," said Steven Kahn (KIPAC).
Before it can take to the sky, SLAC researchers have to prove that it
will work seamlessly in the laboratory.
Testing Detector Prototype
"Early identification of problems is crucial in the overall process of
putting a working instrument into space," said Tune Kamae (AG). "Unlike
traditional accelerator based experiments, GLAST will be totally
inaccessible for repair after launch. This imposes extremely rigorous
standards for the integration and test phase for the detector."
Under the management of Elliott Bloom (EK), the LAT Integration and
Test (I&T) Subsystem team successfully assembled and tested a small
prototype of the LAT detector. According to Elliott, "The testing went
beautifully and we are excited by the results. The whole team worked
really well together and achieved a great deal."
These hardware tests focused on two components of the LAT detector: the
silicon strip tracker and the cesium iodide calorimeter. The tracker, from
Instituto Nazionale di Fisica Nucleare (INFN, Italy), measures the
trajectory and ultimately the source of celestial gamma-rays. The
calorimeter, from the Naval Research Laboratory in Washington, D.C.,
measures the energy of gamma rays. These two components were combined to
create an integrated detector, working together to decipher fingerprints
of gamma rays.
Tucked away in a 6,000 square foot clean room, the LAT team tested the
integrated detector with cosmic ray muons as well as gamma rays generated
by a Van De Graaf accelerator, originally used to test the Crystal Ball
Detector in 1978. Huge samples of data were collected in shifts around the
clock and on weekends.
Technicians Reggie Rogers and Jeff Tice (both REG) got their first
taste of the rigors of space hardware manufacturing as they worked
elbow-to-elbow with fellow aerospace veteran Mark Molini (REG). Rogers
commented, "The manufacturing process for flight hardware is really
impressive in the level of care and detail in documentation of the
process. We’ve really got our work cut out for us for the next couple of
Despite the recent frenzy of the I&T Subsystem, LAT Project Manager
Lowell Klaisner (GLAST) expects the pace will accelerate as the research
continues and more components of the LAT are integrated into the full
detector. "The entire facility will be a beehive of activity when
integration of the LAT is in full swing starting in the summer of 2004,"
Positive results at this early stage in development are promising for
the overall success of the completed LAT. The testing of the integrated
engineering models is a crucial first step towards manufacturing the
entire LAT detector, which will be two orders of magnitude more complex.
The hard work and dedication of the LAT team gives every indication that
SLAC will rise to the challenge of space.