Navigation Links
Higher energies for laser-accelerated particles possible
Date:7/2/2012

The use of compact laser accelerators for cancer therapy with charged particles such as protons could become possible in the future if scientists succeed in generating protons with very high energies. Physicists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) directed the light of the high power laser DRACO perpendicularly and obliquely onto a thin metal foil; thus, permitting them to demonstrate for the first time that accelerated protons follow the direction of the laser light. By incorporating this new data into a conventional model describing the laser particle acceleration, high proton energies which have not been realized so far might become achievable. The results have been published in the scientific journal Nature Communications.

The intense and ultra-short light pulses of the high power laser DRACO can be thought of as disks of about 10 centimeters in diameter and being as thin as a normal sheet of paper. If one of these disks of light is focused onto a thin metal foil, the extreme high electric and magnetic forces will pull negatively charged electrons out of the foil. These electrons will then accelerate positively charged protons away from the foil's surface. To date, many experts have thought that commercially available laser systems would not be suitable for future cancer therapy applications because they have such short laser pulses, and the energy which is achieved by the accelerated protons is correspondingly too low. The results published by the HZDR group demonstrate for the first time that proton energies needed for cancer therapy could, in principle, also be generated from such a short pulse laser. This prospect motivated the Dresden researchers to study the particle acceleration process very closely.

New Two-Phase Model for Laser Accelerated Particles

A light pulse coming from the DRACO laser and directed perpendicular onto a thin metal foil accelerates electrons, and thus also protons, perpendicularly to the foil's surface, just like previous models predict. But that is not the case with a tilted laser pulse. If the angle of the thin light disk is slightly tilted with respect to the axis of propagation, something unexpected happens during the first phase of the particle acceleration. The electrons feel the rotation of the light disk and follow the direction in which the light hits the foil. Moreover, protons are accelerated along this direction as well and, in contrast to the electrons, maintain their direction. This novel observation of the directional dependence permits the Dresden physicists to also look directly at the underlying acceleration process.

"During the first acceleration phase, the distance between the electrons and the foil is extremely small. Once the short laser pulse has pushed them through the foil, they immediately swing back again because the foil has a positive charge. That is one reason why we were very surprised to discover that not only the electrons follow the motion of the laser light, but also the protons exhibit this previously unknown directional dependence," notes the doctoral candidate and main author of the current publication, Karl Zeil. He managed to detect another particular feature which only occurs with ultra-short laser pulses: The initial phase is decisive for the entire acceleration process. During the first 30 femtoseconds that is, one millionth of one billionth of a second, and equal to the length of the laser pulse the acceleration is very efficient. The short and efficient acceleration phase is followed by a longer expansion phase, during which a uniform and symmetrical plasma cloud is formed. The protons, however, gain so much energy during the first phase which, in turn, makes them so fast that they finally can reach higher energies than conventional models would predict.

Precisely how the fast electrons oscillate around the foil, and thus, accelerate the protons, is investigated by the HZDR scientists also with the help of simulations. Karl Zeil: "Experiments and simulations agree quite well with each other. With the newly obtained data we can now extend the presently existing models. This essentially means that ultra-short pulsed lasers like our DRACO laser could potentially be capable of generating protons with sufficiently high energy so that they can be used in future cancer therapy. That we were successful in obtaining these results is both very pleasing and very motivating."

DRACO Being Expanded, PENELOPE Newly Added

The DRACO laser currently reaches a peak power of 150 terawatts this translates into the output of all power plants in the world albeit only for a period of 30 femtoseconds at a time. The laser physicists at the Helmholtz-Zentrum Dresden-Rossendorf want to expand DRACO to 500 terawatts and are currently building a petawatt laser system called PENELOPE. As a modern accelerator technology, particle acceleration with laser light provides considerable advantages when compared to conventional systems: The acceleration distance is much shorter and the costs for such systems are potentially lower. Currently, the OncoRay center, which is jointly supported by the cooperation partners HZDR, University Hospital, and TU Dresden, is building a modern proton therapy facility on the University Hospital's campus. The new facility will be used for cancer research and therapy. For the first time ever, the prototype of a high performance laser will be operated here in addition to a conventional proton accelerator.


'/>"/>

Contact: Anja Weigl
a.weigl@hzdr.de
49-351-260-2452
Helmholtz Association of German Research Centres
Source:Eurekalert  

Related medicine news :

1. Prostate cancer treatment regret is 52 percent higher in men with cardiovascular disease
2. Childless women with fertility problems at higher risk of hospitalization for psychiatric disorders
3. Higher levels of public reimbursement positively influence national birth rates and reduce unmet needs in subfertile populations
4. Asthma Rates Higher Near Busy New York Highway
5. Smallest, Largest Fetuses at Higher Risk of Stillbirth
6. Rate of severe reactions higher than thought in young children with food allergies
7. Higher medical home performance rating of community health centers linked with higher operating cost
8. Higher quality of life seen among regular moderate drinkers than among abstainers
9. Canadian teen moms run higher risk of abuse, depression than older mothers
10. Does More Dental Plaque Mean Higher Chances of Dying From Cancer?
11. Hepatitis B Infection Rates in U.S. Higher Than Thought
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Higher energies for laser-accelerated particles possible
(Date:6/26/2016)... ... June 26, 2016 , ... Pixel Film Studios Released ProSlice Levels, a ... can give their videos a whole new perspective by using the title layers ... Film Studios. , ProSlice Levels contains over 30 Different presets to choose from. ...
(Date:6/25/2016)... ... 25, 2016 , ... Experts from the American Institutes for ... Meeting June 26-28, 2016, at the Hynes Convention Center in Boston. , AIR ... care planning, healthcare costs and patient and family engagement. , AIR researchers will ...
(Date:6/25/2016)... ... 2016 , ... First Choice Emergency Room , the largest network of ... Medical Director of its new Mesquite-Samuell Farm facility. , “We are pleased to ... said Dr. James M. Muzzarelli, Executive Medical Director of First Choice Emergency Room. ...
(Date:6/25/2016)... Montreal, Canada (PRWEB) , ... June 25, 2016 , ... ... the pursuit of success. In terms of the latter, setting the bar too high ... low, risk more than just slow progress toward their goal. , Research from ...
(Date:6/24/2016)... ... ... was in a crisis. Her son James, eight, was out of control. Prone to extreme ... “When something upset him, he couldn’t control his emotions,” remembers Marcy. “If there was ... other children and say he was going to kill them. If we were driving ...
Breaking Medicine News(10 mins):
(Date:6/23/2016)... -- Revolutionary technology includes multi-speaker listening to ... leaders in advanced audiology and hearing aid technology, has ... the world,s first internet connected hearing aid that opens ...      (Photo: http://photos.prnewswire.com/prnh/20160622/382240 ) , ... firsts,: , TwinLink™ - the first dual ...
(Date:6/23/2016)... , June 23, 2016 The vast majority ... outpatient dialysis facility.  Treatments are usually 3 times a ... per visit, including travel time, equipment preparation and wait ... but especially grueling for patients who are elderly and ... skilled nursing and rehabilitation centers for some duration of ...
(Date:6/23/2016)... FRANKLIN, Tenn. , June 23, 2016 ... for automating, integrating and transforming the patient ... launch of several innovative new products and ... depth of its revenue cycle offerings. These ... establish more efficient workflows, remain compliant in ...
Breaking Medicine Technology: