PASER: A Novel Acceleration Scheme Demonstrated

Sep 21, 2006

A group of scientists from the Technion – Israel Institute of Technology has used the Accelerator Test Facility (ATF) at the U.S. Department of Energy’s Brookhaven National Laboratory to demonstrate, for the first time, the feasibility of particle acceleration by stimulated emission of radiation (PASER), a kind of particle analog of the laser process.

The technology may provide a brand new tool for the emerging field of nanoscience because the “cool” electrons produced will enable more precise x-ray probes of ultra-small structures. Both the essence of the concept and the proof-of-principle experiment performed at the ATF are described in an upcoming publication in Physical Review Letters.

“This is the first experimental evidence that energy can be transferred from excited atoms/molecules to free electrons in a coherent way,” said Samer Banna, a co-author on the paper with Levi Schächter and Valery Berezovsky. “In other words, this is the first demonstration of coherent collisions of the second kind.”

A collision of the second kind takes place when a moving electron collides with an excited atom/molecule and energy is transferred from the latter to the former. In coherent collisions, the energy transfer due to multiple collisions may significantly increase the kinetic energy of the moving electrons.

The researchers have shown that energy stored in a carbon dioxide (CO2) mixture is transferred directly to an electron beam, which was initially bunched by the powerful ATF CO2 laser in order to ensure significant energy transfer. Each accelerated electron has undergone roughly two million collisions with excited C22 molecules, generating no heat in the process.

Banna explained the PASER and LASER analogy: “In the latter case, photons traveling through an active medium stimulate the excited atoms, which release their energy in the form of additional photons,” he said. “In the PASER experiment, the active medium surrenders its energy directly to the electrons.”

Although the effect observed in this proof-of-principle experiment is modest, Banna emphasized that future PASER experiments will aim to significantly increase the gain in acceleration.

Accelerator Test Facility: www.bnl.gov/atf

Source: Brookhaven National Laboratory

Explore further: Missing link in metal physics explains Earth's magnetic field

add to favorites email to friend print save as pdf

Related Stories

Recommended for you

Particle physicists discuss JUNO neutrino experiment

14 hours ago

The construction of the facilities for the JUNO neutrino experiment has been initiated with an official groundbreaking ceremony near the south Chinese city of Jiangmen. Involved in the Jiangmen Underground ...

New pathway to valleytronics

Jan 27, 2015

A potential avenue to quantum computing currently generating quite the buzz in the high-tech industry is "valleytronics," in which information is coded based on the wavelike motion of electrons moving through ...

New portable vacuum standard

Jan 26, 2015

A novel Portable Vacuum Standard (PVS) has been added to the roster of NIST's Standard Reference Instruments (SRI). It is now available for purchase as part of NIST's ongoing commitment to disseminate measurement ...

Prototype for first traceable PET-MR phantom

Jan 26, 2015

As cancer diagnostic tools, a new class of imagers – which combines positron-emission tomography (PET) with magnetic resonance imaging (MR or MRI) – has shown promise in the few years since these hybrid ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.