Featured Research

from universities, journals, and other organizations

An Alternative To Giant Cyclotrons

Date:
November 16, 1999
Source:
University Of Michigan
Summary:
University of Michigan researchers have announced a new method to accelerate ions, using powerful light from a table-top laser instead of the radio-frequency waves that have been used for ion acceleration ever since Ernest O. Lawrence invented the cyclotron more than 60 years ago. The new technique allows them to accelerate ions in almost a million-times shorter distance than a cyclotron.

ANN ARBOR --- University of Michigan researchers have announced a new method to accelerate ions, using powerful light from a table-top laser instead of the radio-frequency waves that have been used for ion acceleration ever since Ernest O. Lawrence invented the cyclotron more than 60 years ago. The new technique allows them to accelerate ions in almost a million-times shorter distance than a cyclotron, which uses huge electro-magnets to accelerate atomic particles around a circular path before releasing them at a target.

This new technique may eventually make ion accelerators much more affordable to clinics and hospitals as well as providing doctors with new cancer-treatment capabilities. Besides pioneering the modern era in experimental nuclear and high-energy physics by creating the first controlled beams of energetic ions, Lawrence also used his cyclotron for treating his mother's cancer, which is now the most common application of cyclotrons.

The discovery was made by a research group led by Donald Umstadter, associate professor of electrical engineering and nuclear engineering at the U-M. Earlier this year, the same researchers had first demonstrated ion acceleration by means of focusing their high-power laser beam into a helium gas jet (published in the journal Physical Review E). However, the ions in these early experiments were accelerated in a direction that was perpendicular to the direction of the laser beam and so the ions were not tightly focused into a beam. By replacing the gas with a sheet of aluminum foil, they are now able to accelerate the ions into a confined beam that points almost in the same direction as the laser beam.

"Based on our previous results on gases, we reasoned---as it turns out, correctly---that a solid-density target would make a better ion beam," Umstadter said.

The acceleration process involves several steps that occur when the laser beam is focused onto the foil. The much lighter electrons are first accelerated by the enormous oscillating electric field of the laser light. As these electrons leave the ions behind, a steady electrostatic field is generated, like that of a capacitor. It is this latter field that accelerates protons from the surface of the foil. (A proton is the same as a hydrogen ion.) The protons are accelerated perpendicular to the surface of the foil regardless of the angle at which the laser hits the foil. More than 10 billion ions were accelerated with each laser shot.

This new finding will be announced by U-M research scientist Anatoly Maksimchuk during the annual meeting of the American Physical Society (APS) Division of Plasma Physics, Nov. 15-19, at the Westin Hotel in Seattle.

The announcement coincides with a similar finding to be announced at the same conference by the Lawrence-Livermore National Laboratory, but Umstadter points out that the Livermore laser was the size of a large building instead of a table top. While the U-M team achieved ion energies that were only one-tenth as much as the national lab, they did so with a laser beam that is only one-thousandth the power. This size reduction will be required to make the technique practical for real-world medical applications, such as the preparation of short-lived medical isotopes and tumor treatment.

Another difference is that the area of the region from which the ions originate, which is called the laser focal spot-size, is a 1,000 times smaller in the Michigan experiment than it was in the Livermore experiment or in an ordinary cyclotron. This smaller source may permit the irradiation of a small group of cells, enabling biological research on the early stages of the growth of tumors. Also unlike a cyclotron, the laser-produced protons naturally diverge at a 40-degree angle from their source, which might make it easier to evenly treat a large volume of the body of a cancer patient.

Maksimchuk said, "With our beam of several million-volts energy, we can now produce nuclear reactions and study radiation chemistry with a table-top device." Since the protons in the U-M accelerator are generated in less than a picosecond, or a trillionth of a second, they can be used for radiology on ultrashort time scales.

The Michigan group is now investigating these research applications while building an even smaller laser system, one with the same high peak power but a higher average power, so that they can accelerate a greater number of ions in each second with higher energies. They hope to make the technique practical for clinical applications within the next few years.


Story Source:

The above story is based on materials provided by University Of Michigan. Note: Materials may be edited for content and length.


Cite This Page:

University Of Michigan. "An Alternative To Giant Cyclotrons." ScienceDaily. ScienceDaily, 16 November 1999. <www.sciencedaily.com/releases/1999/11/991116060754.htm>.
University Of Michigan. (1999, November 16). An Alternative To Giant Cyclotrons. ScienceDaily. Retrieved August 2, 2014 from www.sciencedaily.com/releases/1999/11/991116060754.htm
University Of Michigan. "An Alternative To Giant Cyclotrons." ScienceDaily. www.sciencedaily.com/releases/1999/11/991116060754.htm (accessed August 2, 2014).

Share This




More Matter & Energy News

Saturday, August 2, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Tesla, Panasonic Ink Deal To Make Huge Battery 'Gigafactory'

Tesla, Panasonic Ink Deal To Make Huge Battery 'Gigafactory'

Newsy (July 31, 2014) The deal will help build a massive battery factory that Tesla says will produce 500,000 lithium batteries by 2020. Video provided by Newsy
Powered by NewsLook.com
Britain Testing Driverless Cars on Roadways

Britain Testing Driverless Cars on Roadways

AP (July 30, 2014) British officials said on Wednesday that driverless cars will be tested on roads in as many as three cities in a trial program set to begin in January. Officials said the tests will last up to three years. (July 30) Video provided by AP
Powered by NewsLook.com
7 Ways to Use Toothpaste: Howdini Hacks

7 Ways to Use Toothpaste: Howdini Hacks

Howdini (July 30, 2014) Fresh breath and clean teeth are great, but have you ever thought, "my toothpaste could be doing more". Well, it can! Lots of things! Howdini has 7 new uses for this household staple. Video provided by Howdini
Powered by NewsLook.com
Smoked: 2015 Ducati Diavel Vs 2014 Chevy Corvette Stingray Drag Race

Smoked: 2015 Ducati Diavel Vs 2014 Chevy Corvette Stingray Drag Race

Cycle World (July 30, 2014) The Bonnier Motorcycle Group presents Smoked; a three part video series. In this episode the 2015 Ducati Diavel takes on the 2014 Chevy Corvette Stingray Video provided by Cycle World
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins