Rice nuclear scientists design faster, cheaper timing devices

Rice nuclear scientists design faster, cheaper timing devices
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BY JADE BOYD
Rice News Staff

Researchers in
the T.W. Bonner Nuclear Laboratory at Rice University have
found a new use for old technology.

They are using
resistive plate chambers (RPC) in an innovative new precision
timing mechanism. The new timing detectors and related electronic
components promise to be far less expensive than existing
technology in wide use in both particle accelerators and
mass spectrometers.

Due to the market
potential for the technology outside the narrow realm of
particle research, Houston-based Blue Sky Electronics LLC,
has won a $100,000 Small Business Innovative Research (SBIR)
grant from the Department of Energy to develop new electronic
components — dubbed PicoTOF — for Rice’s
detectors. Outside of physics, PicoTOF could prove to be
faster and less expensive than the timing detectors currently
used in the $2 billion time-of-flight mass spectrometry
market.

In particle accelerators,
timing detectors act as extremely precise stopwatches that
physicists use to learn about collisions between subatomic
particles. When protons or neutrons are smashed together
at nearly the speed of light, the force is great enough
to free the quarks and gluons inside. By studying the behavior
of these short-lived particles as they fly away from the
collision, physicists learn more about the basic nature
of the universe.

Rice’s timing
detectors work by measuring time-of-flight (TOF), the amount
of time it takes for a particle like a proton to travel
from the point of collision to the detector. Blue Sky’s
job is to build electronics that are capable of measuring
the incredibly short flight times to an accuracy of 50 picoseconds,
or 50 trillionths of a second. To give an idea of how precise
that is, light — which travels 186,000 miles in one
second — moves just half an inch in 50 picoseconds.

“Time-of-flight
detectors, which were pioneered by particle physicists in
the 1940s, are now commonplace in microbiology labs the
world over,” said Billy Bonner, director of the Bonner
Lab and professor of physics and astronomy. “Rice’s
new RPC detectors and Blue Sky’s PicoTOF electronics
continue that tradition, pushing the limits of technology
to provide better, cheaper measurements.”

Based on preliminary
data, Rice’s new RPC detectors will provide a 50 percent
performance increase over timing detectors based on phototubes
and scintillators at one-fifth the cost. A test batch of
Rice’s new RPC detectors is gathering data in experiments
at the Relativistic Heavy Ion Collider at Brookhaven National
Laboratory on Long Island, N.Y. Bonner said he hopes to
analyze the data from those tests early next year.

The RPC detectors
are constructed of seven panes of glass, each separated
by a thin chamber filled with freon gas. When a subatomic
particle strikes the first layer of gas, it dislodges electrons,
which strike the second layer, creating more electrons,
which strike the third layer and so on. Each successive
reaction involves more electrons, thus a higher electrical
charge, but the final output is still extremely small —
only about 10,000 electrons. Amplifying this miniscule signal
and converting it into digital data that can be stored and
analyzed by a computer is the task of PicoTOF.

“You can
get lab-grade electronics that perform at this level, but
they cost about $1,000 per channel,” said Lloyd Bridges
’82, president of Blue Sky Electronics. “For a
particle accelerator with more than 20,000 channels, that’s
cost-prohibitive. Our prototype, due early next year, will
be smaller and will cost closer to $100 per channel.”

PicoTOF will
combine the best elements of TOF electronics used in physics
and biology. PicoTOF will be about one-tenth the size and
one-tenth the cost of the electronics used in particle accelerators
today. That will give it a form factor similar to the electronics
found in today’s mass spectrometers, but with 10 times
the precision.

Bridges said
Blue Sky and Rice’s Bonner Nuclear Laboratory will
apply next spring for a Phase II SBIR grant of $750,000
that will be used to develop PicoTOF for full production.