Subscribe free to our newsletters via your
. 24/7 Space News .

Subscribe free to our newsletters via your

Plasma processing technique takes SNS accelerator to new energy highs
by Staff Writers
Oak Ridge TN (SPX) Mar 08, 2016

Behind the work station, cryomodule 19 undergoes in-situ plasma processing inside the SNS linac. The inset shows a 6-cell cavity with monitored plasma inside each cell. Image courtesy Genevieve Martin and ORNL. For a larger version of this image please go here.

A novel technique known as in-situ plasma processing is helping scientists get more neutrons and better data for their experiments at the Spallation Neutron Source at the Department of Energy's Oak Ridge National Laboratory.

"Plasma cleaning is a well-known technique in electrostatics," said ORNL's Research Accelerator Division Director Kevin Jones, "but it has not been applied before to superconducting cavities, and there are some interesting tricks that you have to develop and apply in order to make it all work."

SNS's linear accelerator, or linac, features a set of 20-plus cryomodules - large, barrel-shaped capsules, necessary for focusing and accelerating the proton beam. Inside each cryomodule are 3-4 niobium cavity strings, accordion-like components bathed in liquid helium that keeps the cavities cold to aid in generating very strong electrical fields that drive the beam's acceleration.

Jones explained that over the years trace amounts of hydrocarbon contamination builds up inside the niobium cavities, lessening their ability to sustain high electrical fields, and thus decreasing the beam's potential energy. The conventional response to the problem would be to physically take the cryomodules offline, disassemble them, remove the contamination using ultra-pure water or a chemical rinse, and then finally put everything back together - a labor intensive and costly process.

ORNL staff scientist Marc Doleans and postdoctoral researcher Puneet Tyagi found a better solution. Together they led a team of technicians from SNS's Superconducting Linac Systems Group that undertook a program of rigorous surface science and bench-top experiments with room-temperature cavities that culminated in a series of trial procedures using an offline, spare cryomodule.

"Essentially what they're doing is using hot plasma to burn off the hydrocarbons on and just below the surfaces [inside the niobium cavities]. They're using an inert gas with a few percent of oxygen. Basically, the oxygen gobbles up all the bad atoms off the surface of the niobium, and afterwards everything gets pumped out as a gas," Jones said. "It's just cleaning off junk on the surface - kind of like polishing your car."

After the trial procedures were complete, the team tested the cryomodule's performance and saw a significant improvement. That gave the go ahead for the team to carry out the in-situ procedure in the accelerator tunnel during the facility's scheduled winter maintenance outage.

As expected, the procedure was a success. Not only did the team do in 3 weeks what would have taken 6 to 8 months using conventional methods, but furthermore, subsequent testing recorded an energy gain of 11 million electron volts (MeV). The increase from 938 to 949 MeV is a big step forward, according to Jones.

In addition to a few other upgrades, he said, "Today we're running the accelerator at the highest beam energy ever in neutron production at 957 MeV. If we use this procedure on, say, 5 more cryomodules, and we get equivalent gains, we can easily get up to operating at our design energy of 1,000 MeV."

Ramping up the power to the SNS proton beam enables the production of more neutrons for the thousands of scientists who visit the DOE Office of Science User Facility to conduct research.

The work is already generating a lot of buzz, and it's being viewed very positively, Jones says. In addition to their recent publication in the scientific journals NIM A and Applied Surface Science, the team has been asked to collaborate with other national labs conducting research into superconducting accelerators.

"This is high-profile stuff," Jones said. "It saves us an enormous amount of money, effort, and time in improving the performance of those cavities, and our investment has been worth every penny."

Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once

credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly

paypal only


Related Links
Oak Ridge National Laboratory
Powering The World in the 21st Century at

Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks DiggDigg RedditReddit GoogleGoogle

Previous Report
Understanding how turbulence drains heat from fusion reactors
Princeton NJ (SPX) Feb 24, 2016
The life of a subatomic particle can be hectic. The charged nuclei and electrons that zip around the vacuum vessels of doughnut-shaped fusion machines known as tokamaks are always in motion. But while that motion helps produce the fusion reactions that could power a new class of electricity generator, the turbulence it generates can also limit those reactions. Now, physicists at the U.S. D ... read more

China to use data relay satellite to explore dark side of moon

NASA May Return to Moon, But Only After Cutting Off ISS

Lunar love: When science meets artistry

New Lunar Exhibit Features NASA's Lunar Reconnaissance Orbiter Imagery

Great tilt gave Mars a new face

Space simulation crew hits halfway mark til August re-entry

Proton-M carrier rocket assembled ahead of Mars Mission

Monster volcano gave Mars extreme makeover: study

Sore, but no taller, astronaut Scott Kelly adjusts to Earth

Test Dummies to Help Assess Crew Safety in Orion

Commercial Crew: Building in Safety from the Ground Up in a Unique Way

Russian company set to usher in era of suborbital tourism

Aim Higher: China Plans to Send Rover to Mars in 2020

China's lunar probe sets record for longest stay

China to Launch Over 100 Long March Rockets Within Five Years

Moving in to Tiangong 2

International Space Station's '1-year crew' returns to Earth

Scott Kelly and Mikhail Kornienko return to Earth after One-Year Mission

Paragon wins NASA ISS water processor development contract

NASA's Science Command Post Supports Scott Kelly's Year In Space

SpaceX launches SES-9 satellite to GEO; but booster landing fails

US Space Company in Talks With India to Launch Satellite

At last second, SpaceX delays satellite launch again

Arianespace Soyuz to launch 2 Galileo satellites in May

Evidence found for unstable heavy element at solar system formation

Imaging Technique May Help Discover Earth-Like Planets Around Other Stars

Newly discovered planet in the Hyades cluster could shed light on planetary evolution

Imaging technique may help discover Earth-like planets

New radar system set for testing

Scaling up tissue engineering

UMass Amherst team offers new, simpler law of complex wrinkle patterns

How metal clusters grow

Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News

The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement