Medical Device & Diagnostic Industry Magazine
MDDI Article Index
Originally Published MDDI July 2005
|Close-up of the lithium tantalate crystal. A tungsten needle is used as an ion source.|
Sustainable nuclear fusion is the Holy Grail for many scientists. One research team has gotten closer, inventing a surprisingly simple room-temperature desktop fusion machine. Although it won't power entire cities, the device may be used in imaging or radiation therapy.
|Brian Naranjo (left) and Seth Putterman have created a fusion device that could
resonate in the device industry.
Researchers from the University of California, Los Angeles (UCLA), are looking for ways to use the long-awaited technology. Targeting cancer cells for radiation could be an option in the near future. There is also a possibility that small pieces of crystal injected into the body can create radiation directly, says Seth Putterman, one of the researchers and a professor of physics at UCLA. Other team members are Brian Naranjo, a physics graduate student, and James Gimzewski, professor of chemistry.
The device relies on an asymmetric chunk of lithium tantalite crystal. Slowly heating the pyroelectric crystal from freezing to room temperature causes positive and negative charges to migrate to opposite ends of the crystal and form an electric field.
The team conducted experiments using the crystal to create a low-power cold fusion device.
|A cross-sectional image of the ion beam generated from the crystal.|
The crystal was slowly heated from –33° to 7°C in approximately 31¼2 minutes in a deuterated atmosphere. Deuterium is an isotope of hydrogen. The deuterium ions accelerated to about 1% of the speed of light. Once the beam had traveled about 1 cm, it struck the tip of a tungsten needle connected to the crystal. The beam then fused with the deuterium nuclei on the surface. The fusion produced 400 times more neutrons than the lab's background measurements.
According to Putterman, the process emits 1000 neutrons per second and can be sustained for up to 8 hours. “The fusion is a main point, but the x-ray portion is also a very serious part of the technology,” Putterman says.
Eventually this could lead to some intriguing solutions for treating cancer. “We want to shrink the crystal down to 1 mm,” he says. “From there, it can be injected into the body to deliver individual radiation doses to tumors.”
For now, research in fusion technology will be continued by UCLA, but could get funded by some other program. The researchers say that this method of producing nuclear fusion won't be useful for normal power generation, but it might find applications in the generation of neutron beams for research purposes, and perhaps as a propulsion mechanism for miniature spacecraft.
As for bringing a finished device to market, Putterman is hands-off, saying he prefers the research. “Our job is proof of principle—we'll leave the marketing to the engineers.”
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