Ultrafast laser-driven ion interactions in matter: Evolving dose distribution at the nanoscale and nonlinear response

Lead Research Organisation: Queen's University of Belfast
Department Name: Sch of Mathematics and Physics

Abstract

In physics, scaling laws provide a dual function. First, they can reveal the underlying physical mechanisms that govern a system by establishing how the system responds to changes or perturbations. This is particularly true of nonlinear scaling laws where small changes in an input perturbation can lead to dramatic changes in the response of the system. Secondly scaling laws provide researchers with a tool that they can use to predict how a system will evolve for a given set of input parameters. This is a crucial step towards providing highly-targeted, cutting-edge applications. It is within this framework that we propose to study the ultrafast dynamics that result from ion interactions in matter to determine how the characteristic response of the medium scales with the incident ion flux.

To study any ultrafast process directly it is critical that the perturbation causing the system to change is significantly shorter than the natural recovery time of the system. If the perturbation is significantly longer that this recovery there will be repeated cycles of excitation and relaxation within a single interaction. This inhibits the ability to extract fundamental information about the system without complicated approximations and assumptions. Unfortunately, to date, this has been the overriding problem for the study of ion interactions in matter. The ion pulses that have been available from large accelerator facilities have been 100's of picoseconds in duration which is significantly longer than the femtosecond and few picosecond characteristic recovery times of matter in response to irradiation. Accordingly, existing experimental results relating to the earliest accessible stages of ion matter interactions have prohibitively large associated uncertainties.

Our approach overcomes this issue by generating ultrafast pulses of ions using laser driven ion accelerators. This performance will allow the stopping of energetic ions (> 1 MeV/nucleon) in matter to be studied on femtosecond and picosecond timescales. We will use this capability to understand how the resulting pathways to equilibrium can be controlled by varying the incident flux of ions and investigate the new possibilities this offers for advanced applications in both radiation chemistry and hadrontherapy.

The Centre for Plasma Physics in Queen's University Belfast is currently constructing the world's highest energy few-optical-cycle laser system, TARANIS-X, due to come online in late 2016. This unique environment will allow us to generate the shortest pulses of ions produced in the laboratory to date. With this state of the art facility it will be possible to test, in real time, the fundamental limits of ion interactions in matter. Understanding this behaviour is a key goal of this research. In particular extending these experiments to ion interactions in water will allow us to investigate the potential for new modalities of dose delivery during hadron (or ion beam) therapy. This is because water makes up over >70% of human cells and so it makes for an ideal system in which to study the effects of ionising radiation in the human body.

Finally, one of the key motivators for this proposal is the indication of nonlinear response with respect to ion flux in low temporal resolution experiments performed to support the scientific case for this work. Together with our international partners in Germany (Munich) and the U.S. (Texas) we will investigate multiple different interaction regimes to determine the scaling of this nonlinear response and, in partnership with the GEANT4 DNA collaboration, we will develop numerical approaches to form a clear understanding of the scaling law (or laws) that governs it.

Planned Impact

The impacts generated by this research will cut right across the socio-economic spectrum. For the first time it will be possible to quantify the fundamental interaction of ions with matter allowing researchers to determine how these interactions scale with the flux of incident ions. This opens the possibility of harnessing these interactions directly to increase efficiency and safety for applications in manufacturing and healthcare. The details of the expected impacts are described below under 4 distinct headings.

Knowledge
The development of cutting edge science using the world leading laser capabilities available in Queen's University Belfast will contribute directly to the UKs ability to drive the next generation of technology and applications for a knowledge based economy. We will also capitalise on the outputs of our research to inspire the next generation of young children to become involved in science. Through our extensive public engagement programme that includes the Northern Ireland Science Festival, we will demonstrate to a brand new audience how ion beams can change the world around us and how the TARANIS-X laser is leading the way in shaping this future technology.

People
This project will train at least 5 people (3 PDRA and 2 PhDs, with the potential for an additional 2 PhDs in coming years, bringing the total to 7) in world leading technologies based on ultrafast science. These people will become the next generation of scientists who lead and innovate. This project will also offer them the opportunity to travel to international laboratories and to present results at international conferences creating the ideal platform for exposure to different practices and to engage in knowledge transfer with groups from outside the UK.

Economy
Ion beam based manufacturing processes for future technologies in the semiconductor industry have the potential to revolutionise how integrated circuits are constructed and metrologised on the production line. This proposal will study how radiation induced processes in semiconductor industry relevant materials (i.e. SiO2) scale with the incident ion flux so that novel capabilities can be tailored to an exceptionally high degree of accuracy. Also, as electronic devices shrink to ever smaller dimensions it will become increasingly important to understand how radiation induced processes scale with dimensionality for the deployment of circuits in radiation harsh environments such as in nuclear engineering and deep space travel. Through our use of nanostructured media it will be possible to determine exactly how reducing the dimensionality can affect the recovery time of the material and how solutions can be found to overcome the resulting problems.

Society
One very clear impact from the proposed research is the advance in healthcare for society it will deliver. At key objective of our proposed research is to examine the fundamental interaction of ions in water and reveal how ion flux determines the production of the radical species that take part in killing cancer cells for hadrontherapy. We will also the study the role of predicted shock induced delay in the formation of these radical species, its potential role in dose fractionating (or time scale for recovery) and how this process scales with ion flux. The predicted nonlinearity in the production of radicals with respect to ion flux also offers a brand new approach to enhanced protection for tissue surrounding a deep seated tumour volume. In particular, the pathways towards a 'crossfire' treatment technique will be investigated. In this scheme multiple low dose beams are overlapped in the tumour volume leading to nonlinear growth of radicals in the tumour volume while leaving the surrounding tissue exposed to significantly lower risk of damage and cell death through radiation induced processes. This, by extension, will lead to increased patient safety and reduced requirement for treatment aftercare.
 
Description Erasmus Plus
Amount £150,000 (GBP)
Organisation European Union 
Sector Public
Country European Union (EU)
Start 10/2017 
End 10/2019
 
Description CEA Saclay collaboration 
Organisation Saclay Nuclear Research Centre
Country France 
Sector Public 
PI Contribution WE performed and designed experiments on both the Gemini laser system at RAL and the ultrafast laser system at CEA Saclay
Collaborator Contribution Provide staff and expertise for experiments and dedicated access to a world class laser facility
Impact 3 papers ( 1 PRL, 1 Nature Communications, I New Journal of Phyiscs) Invitations to further experiments
Start Year 2010
 
Description Helmholtz institute Jena 
Organisation Friedrich Schiller University Jena (FSU)
Country Germany 
Sector Academic/University 
PI Contribution WE attended and designed new experiments on the Jeti laser in Jena
Collaborator Contribution Access to world class laser facilities, plasma mirror setup and cutting edge diagnostic suite
Impact > 6 published articles (PRL, 3 invited talks at international conferences
Start Year 2010
 
Description Partrnership with CALA in Munich 
Organisation Ludwig Maximilian University of Munich (LMU Munich)
Country Germany 
Sector Academic/University 
PI Contribution Expertise in ultrafast laser ion interactions with matter
Collaborator Contribution Access to cutting edge laser facilities
Impact Not applicable yet - early stage of collaboration
Start Year 2016
 
Description TEI Crete collaboration 
Organisation Technological Educational Institute of Crete
Country Greece 
Sector Academic/University 
PI Contribution Travelled and performed experiments at the ultrafast laser system in Rethymno, Crete
Collaborator Contribution They provided access to their laser system at not cost and full time experimental support
Impact 3 publications, 1 PRL, 1 New Journal of Physics and 1 Optics letters Plans and invitations for future experiments
Start Year 2010
 
Description Texas Petawatt, Austin Texas U.S. 
Organisation University of Texas at Austin
Country United States 
Sector Academic/University 
PI Contribution We are working on novel diagnostics for studying laser driven electrons and ions
Collaborator Contribution Access has been granted to laser experimental area and target fabrication
Impact As a very new collaboration the outcomes are currently in preparation, but we anticipate
Start Year 2015
 
Description Crete summer school 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact Creating awareness to international PhD students about on going work in relativistic laser plasmas and attosecond sources

Experiments planned, international networking, invited talks
Year(s) Of Engagement Activity 2009,2010,2011,2012,2013
 
Description Cross border schools initiative 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Schools
Results and Impact School students interest in scientific discussions

Students planning to visit lab, cross border initiative
Year(s) Of Engagement Activity 2012,2013,2014
 
Description Incredible power of light roadshow 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact We hosted and provided full time staffing for the Incredible power of light roadshow from the STFC in the Ulster Museum during February and March 2015. Our active participation in this public out reach event saw over 10,000 members of the public and over 1000 pupils from regional (Northern Ireland) schools. We demonstrated the exhibits and informed attendees about how to pursue careers in science, technology engineering and mathematics with particular emphasis on laser and light based technologies. Since this was the first year it was difficult to directly measure impact. However our success saw my group invited to return to present the exhibits again the following year (2016).

Also the impact on regional schools was tangible with over 10 requests from individual school groups to provide year round displays in public forums with dedicated exhibitors such as those provided by my group.
Year(s) Of Engagement Activity 2015
 
Description Laser lab meeting 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Participants in your research and patient groups
Results and Impact Talk lead to discussion about future directions for Laser-lab Europe

Invitations to perform experiments
Year(s) Of Engagement Activity 2012,2013,2014
 
Description Lasers live demonstration, Northern Ireland Science festival 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact In 2015 the inaugural Northern Ireland Science festival was held. Following our successful collaboration with Ulster museum with the STFCs Incredible Power of Light roadshow we were invited to build and demonstrate a Laser's Live exhibition in the Foyer of the Ulster Museum. This highly visible location saw nearly 11,000 members of the public attend live demonstrations of how light energy can be harnessed over an 9 day period in 2015.

This was so successful the Ulster Museum invited us to return for an extended period in 2016, extending our reach beyond that of the Northern Ireland Science festival for a 12 day residence in the Foyer. This saw > 18,000 attendees to the museum visit our live demonstrations

We performed detailed metrology in 2016 with over 1000 questionnaires completed by school students and members of the public with ages ranging from 3 - >60 years. The results of these questionnaires are currently being processed but the response has been overwhelming.

All numbers for attendance are official numbers of the Ulster Museum.
Year(s) Of Engagement Activity 2015,2016
 
Description Lasers live demonstration, Northern Ireland Science festival 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Over 20,000 members of the public attended our Lasers live event held in the Ulster museum as part of Northern Ireland Science festival.
Year(s) Of Engagement Activity 2018
 
Description Late Lab 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact As part of the Northern Ireland Science festival we have presented live demonstrations at the Late Lab showcase event of how light can be used to change our world to members of the public. On both occasions over 1000 members of the public attended our stands and interacted with our demonstrators in a 1 -1 basis in an very different setting to what is normal of a scientific setting.
Year(s) Of Engagement Activity 2015,2016
URL https://www.youtube.com/watch?v=oFN3JCAgj58
 
Description Northern ireland Science Festival 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Over 20,000 members of the public attended our Lasers live event held in the Ulster museum as part of Northern Ireland Science festival.
Year(s) Of Engagement Activity 2016,2017
 
Description UCD Japan Ireland Initiative 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other academic audiences (collaborators, peers etc.)
Results and Impact Generate new collaborative links in Japan, investigate novel funding streams

New collaborations forged, invitations to international labs for experiments
Year(s) Of Engagement Activity 2012,2013,2014
 
Description W5 Late 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact New W5 late activity - >1500 members of the public
Year(s) Of Engagement Activity 2018