Researchers generate proton beams using a combination of nanoparticles and laser light

September 30, 2016, Ludwig Maximilian University of Munich
Researchers generate proton beams using a combination of nanoparticles and laser light
The Texas Petawatt laser pulse (red) is focused onto a levitating microsphere target. The immense laser-intensity causes the fierce explosion of the microsphere, thereby generating potentially useful energetic ions from an ultra-small source (blue). Credit: Tobias Ostermayr

Light, when strongly concentrated, is enormously powerful. Now, a team of physicists led by Professor Jörg Schreiber from the Institute of Experimental Physics – Medical Physics, which is part of the Munich-Centre for Advanced Photonics (MAP), a Cluster of Excellence at LMU Munich, has used this energy source with explosive effect. The researchers focus high-power laser light onto beads of plastic just a few micrometers in size. The concentrated energy blows the nanoparticles apart, releasing radiation made up of positively charged atoms (protons). Such proton beams could be used in future for treating tumors, and in advanced imaging techniques. Their findings appear in the journal Physical Review E.

At Texas Petawatt Lasers in Austin, Texas, the LMU physicists concentrated so strongly on plastic nanobeads that these essentially exploded. In the experiment, approximately one quadrillion billion photons (3 times 1020 photons) were focused onto microspheres of about 500 nanometers in diameter. Each bead consists of about 50 billion carbon and hydrogen atoms and is held in suspension by the electromagnetic fields of a so-called "Paul trap", where the laser beam can irradiate them.

The laser radiation rips away some 15 per cent of the electrons bound in these atoms. The remaining, positively charged atomic nuclei are then violently repelled, and the nanospheres explode at speeds of around 10 per cent the speed of light. The radiation from the positively charged particles (protons) then spreads out in all directions.

This mode of production of proton beams with laser light promises to open up new opportunities for nuclear medicine – for example, in the fight against tumors. At present, proton beams are produced in conventional accelerators. In contrast, laser-generated proton beams open the door to the development of novel, perhaps even cheaper and more efficient, methods of treatment. The Munich-based team led by Jörg Schreiber has hitherto produced proton radiation using a diamond-like film, which is targeted by extremely strong laser light. The proton radiation thus emitted could then be directed onto the body of a patient.

The ability to produce radiation by the explosive disintegration of plastic nanobeads might even allow the nanoparticles to be placed inside a tumor, and be vaporized with laser light. Thus proton beams could be put to work in destroying tumors without causing damage to surrounding healthy tissue.

Explore further: Researchers make proton radiation in cancerous tissue visible using ultrasound technology

More information: T. M. Ostermayr et al. Proton acceleration by irradiation of isolated spheres with an intense laser pulse, Physical Review E (2016). DOI: 10.1103/PhysRevE.94.033208

Related Stories

Focused laser power boosts ion acceleration

August 7, 2015

An international team of physicists has used carbon nanotubes to enhance the efficiency of laser-driven particle acceleration. This significant advance brings compact sources of ionizing radiation for medical purposes closer ...

Recommended for you

Coffee-based colloids for direct solar absorption

March 22, 2019

Solar energy is one of the most promising resources to help reduce fossil fuel consumption and mitigate greenhouse gas emissions to power a sustainable future. Devices presently in use to convert solar energy into thermal ...

Physicists reveal why matter dominates universe

March 21, 2019

Physicists in the College of Arts and Sciences at Syracuse University have confirmed that matter and antimatter decay differently for elementary particles containing charmed quarks.

ATLAS experiment observes light scattering off light

March 20, 2019

Light-by-light scattering is a very rare phenomenon in which two photons interact, producing another pair of photons. This process was among the earliest predictions of quantum electrodynamics (QED), the quantum theory of ...


Adjust slider to filter visible comments by rank

Display comments: newest first

not rated yet Sep 30, 2016
More like paired positrons from photons , ,you are just measuring the charge signature as positive and labeling it protons ,
not rated yet Sep 30, 2016
Those paired positrons out of a photon hace an electron in the middle that mass ,fools you into thinking proton , but the 2 positrons quantum charge mass together on that electron are ,333 larger that the electrons quantum mass charge so it measures dominant positive charge on your instruments
not rated yet Sep 30, 2016
Photons do not contain protons, in there make up the are a balanced charged magnetic construction consisting of 2 electrons and 3 positrons that together have equal charges against each other in quantum charge mass , in negitive and positive charge mass
not rated yet Oct 01, 2016
Too bad they couldn't produce neutron outputs.

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.