New developments for ALICE MasterClasses and the new Particle Therapy MasterClass
NNew developments for ALICE MasterClasses and the newParticle Therapy MasterClass
Łukasz
Graczykowski ∗ , , Piotr
Nowakowski , ∗∗ and Panagiota
Foka , ∗∗∗ on behalf of the IPPOG Collaboration Faculty of Physics, Warsaw University of Technology, Koszykowa 75, 00-662 Warszawa, Poland Faculty of Electronics and Information Technology, Warsaw University of Technology, Nowowiejska15 /
19, 00-665 Warszawa, Poland GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Planckstrasse 1, 64291 Darmstatd, Ger-many
Abstract.
International MasterClasses (IMC), an outreach activity of the Inter-national Particle Physics Outreach Group (IPPOG), has been bringing cutting-edge particle physics research to schoolchildren for over 15 years now. All fourLHC experiments participate in the event, including ALICE, the experiment op-timised for the study of heavy-ion collisions. Heavy-ion physics is actively con-tributing to IMC with new developments such as experimental measurementsbut also applications for society, such as treatment of cancer with ions. In par-ticular, ALICE provides three MC measurements related to the main observ-ables used to characterize the properties of the produced Quark-Gluon Plasma.Historically, those MC measurements were developed independently, inherit-ing from the first one, by several ALICE groups. Since all of them are basedon the ROOT EVE package, a project to integrate them into a common frame-work was undertaken. ALICE delivers now a single and easy-to-use application,compiled under Linux, MacOS, and, for the first time, Windows. Then, in linewith current IPPOG goals to increase the global reach and scope of the IMCprogramme a newly developed measurement on medical applications of parti-cle physics, the Particle Therapy MasterClass (PTMC) was introduced in theIMC2020 programme. It is a simplified version of matRad, a MATLAB-basedtoolkit for calculation of dose deposition in the body and allows for planningof radiotherapy using di ff erent modalities and highlighting the benefits of treat-ment with ions. The International Particle Physics Outreach Group (IPPOG) [1] is a collaboration of particlephysicists and engineers, science educators and communication specialists from all over theworld, with the aim of communicating the fundamental particle physics research to generalpublic. The “International MasterClasses – Hands-on Particle Physics” (IMC) [2] is the lead-ing activity of IPPOG, which aims at providing high school students with access to particle ∗ e-mail: [email protected] ∗∗ e-mail: [email protected] ∗∗∗ e-mail: [email protected] a r X i v : . [ phy s i c s . e d - ph ] J u l hysics data with dedicated packages of analysis software and instructions. Every year inthe period from February to April, students are invited to one of the participating universitiesor research laboratories to attend particle physics lectures and perform measurements usingreal data from the Large Hadron Collider (LHC) [3] experiments. All four LHC experiments(ATLAS, CMS, LHCb, and ALICE) participate in the IMC providing various measurementson di ff erent aspects of particle physics. All MC measurements use especially prefiltered sam-ples of real collision data, recorded by the respective experiment. In most cases, they are builton visualisation tools that are part of the experiment’s software framework. Hence, studentshave the possibility to work on real data as scientists do. Thousands of students from acrossthe globe attend the event annually.Recently, the increase of the global reach and scope of the IMC programme has becomeone of the main goals of IPPOG. Several new measurements coming from non-LHC and non-CERN experiments are currently in various stages of preparation. Moreover, the expansionof IMC is not limited to fundamental research only. Of particular interest are applicationsof technologies developed initially for particle physics that our society benefits from. Forinstance, medicine is the field where such a benefit is undoubtedly the most obviously vis-ible and has a direct impact on our life. In particular, cancer has recently become the mostcommon cause of death in high-income countries [4].Heavy-ion physics is present within the International MasterClasses since the beginningof the LHC IMC programme, with continuous developments aiming at expanding in scopeand reach. In line with the physics research of typical heavy-ion experiments, three ALICEmeasurements were developed based on actual data analysis of the experiment. They cor-respond to the most important observables studied to characterise the properties of matterproduced in energetic collisions of ions or protons. Then, with the aim to highlight applica-tions from fundamental research for society, the new Particle Therapy MasterClass (PTMC)was introduced in the 2020 edition of IMC for the first time, familiarising students with theactual operation technique used for cancer treatment employing photons, protons or carbonions. As a good example is presented the fact that for this therapy the heavy-ion research cen-tre GSI, Germany, played a pioneering role in Europe, in the 90s, leading to the constructionof the HIT therapy centre in Heidelberg.Both MasterClasses had challenging requirements on software developments as they hadto be realistic but also easy to use. ALICE (A Large Ion Collider Experiment) [5] is the LHC [3] experiment dedicated to thestudy of heavy-ion collisions. The primary objective of ALICE is the study of the propertiesof the produced deconfined state of matter, the quark-gluon plasma (QGP) which, accord-ing to theory, existed in the very beginning of our Universe. A number of observables arestudied to fully characterize the hot and dense matter produced in the laboratory in energeticcollisions of lead nuclei and systematically compare them with proton-proton collisions ofdi ff erent particle multiplicities. ALICE developed MasterClass measurements for three ofthe main observables: a) strange particles production, b) nuclear modification factor and c)J / Psi production.
The ALICE software is based on the ROOT framework [6] which is used for the experi-ment’s data processing and analysis. Consequently, the ALICE MasterClasses are also basedn ROOT to fulfil the requirement of the MC to be as close as possible to the experimentalreality. The advantage is that school-children are thrilled to know that they use the very sametools as the ALICE scientists. The downside is that the installation of the ROOT framework isrequired which makes the preparation process cumbersome. To bypass this issue Virtual boxinstallation was used. Historically, the MasterClass on strangeness was developed first [7] andthen adapted for the nuclear modification factor [8]. Those fully developed and documentedMC measurements are included in the IMC schedule. The third MC on the J / Psi measure-ment was also developed with starting point the existing MC software and is currently beingfinalised. Despite their common origin they soon diverged as di ff erent groups and individualsimplemented additional functionality or corrections in the individual computer codes with notracking of di ff erent versions. In order to facilitate maintenance and coherency, a concertede ff ort started as a summer student project in 2018, followed by an EU-funded grant of theWarsaw University of Technology group, with the aim to unify the existing MC code inte-grating it in a single framework, taking advantage at the same time of the upcoming enhancedfunctionality of ROOT 6. The new framework, where all three ALICE MC are integrated, isnow used in the IMC 2020 schedule. Figure 1 represents the new design of the ALICE MasterClass framework at the functionallevel. The aim was to identify common elements such as the Event Display and readingof experimental data files. Hence, the main component of the program is an instance of
Event Display , which handles the 3D detector display and track visualisation. Selecting ameasurement from the main menu activates one of the
Exercise objects, which control thescenario of each task. This object can transform the
Event Display ’s default GUI by injectingone or more
Widget elements, such as particle mass calculator or particle count histogram.In this way the GUI can be dynamically modified to suit a specific measurement. Anothercommon functionality, reading of the experiment data files, is realized by another object —the
VSD Reader . The new development also supports translation of the program into otherlanguages, which can be helpful for students not proficient in English. The
GUITranslation object is responsible for serving the translated text of instructions, error messages, buttondescriptions etc. for both
Exercise and
Event Display . Fig. 1.
Structural diagramof the new ALICEMasterClass frameworkintegrating the threeexisting measurements.
The new framework is distributed and installed as compiled binary standalone applicationwhich presents advantages compared to the previous script-based and interpreted form of theproject in terms of size and performance. The new version ROOT 6 was used, replacingROOT 5. Although ROOT itself is still required for the MasterClass to function, it waspossible to bundle it with the application, eliminating the need to install it separately. Theembedded” ROOT is not installed in any global directory and will not interfere with anyprevious ROOT installations on the system. Thanks to the improvements made in this ROOTversion, it was possible to port the ALICE MC framework to other major operating systems(both Windows 10 and MacOS X), which hugely improves the accessibility of the program.For the first time, it allows the participating students to use the ALICE MC framework athome on their own computers, regardless of the operating system. In addition, a VirtualBoxdisk with preinstalled Ubuntu and the ALICE MC is also provided.To create the package for Linux systems a
AppImage framework was used, which bundlesthe whole application (executable, ROOT framework and experimental data) into a singlefile, which can be executed via a double-click gesture like any other program. For MacOSX a standard pkg installer was created which places the MC among other programs inthe
Applications directory. For Windows a standard .msi installer was created which can beused to place the MC app in
Program Files directory with Desktop and Start Menu shortcuts.Figure 2 shows the event display of the strangeness MC in the new framework.The new ALICE MC suite of applications can be downloaded from the o ffi cial ALICEMC website [9]. Fig. 2.
Main window of the ALICEMasterClass (production of strangeparticles measurement) showing the3D visualisation of the ALICEdetector with reconstructed particletracks from pp collisions at √ s = The list below summarises all recent changes made in the ALICE MasterClass framework: • ALICE MasterClass as an optimized compiled binary, not a set of scripts, • Portable code — a version available for Windows, Linux and MacOS X, • ROOT bundled with the app, not required to install separately, will not a ff ect other existinginstallations, • Many bug fixes such as restoring the functionality of system minimize and exit buttons, • Extendable framework for future exercises, • Possible to translate the app into other languages, language selection at runtime.
Particle Therapy MasterClass
With the aim to enhance awareness on the benefits for society, and in particular for health, thatresult from fundamental research, a new MC package was developed: the Particle TherapyMasterClass (PTMC). It is included for the first time in the o ffi cial schedule of IMC2020after a very successful pilot in April 2019 with the participation of GSI, CERN and DKFZHeidelberg [10]. This core team represents the world leading research institutes in theirdomain that also provided tangible applications for health: at GSI the first 450 patients inEurope were experimentally treated with carbon ions [11], at CERN the Proton-Ion MedicalMachine Study (PIMMS) design team was hosted [12] and DKFZ is the German Cancerresearch centre next to the HIT Heidelberg ion therapy facility [13].Students have the opportunity to realise that very basic physics principles constitute thebasis of treatment of cancer tumours and that very same instruments used in physics researchlaboratories are also used in cancer therapy facilities. In particular, it is illustrated that as par-ticle accelerators evolve and become more powerful and e ffi cient, their medical applicationsbecome more and more important and accessible.The PTMC is based on the matRAD open-source software [14] which itself is based onMATLAB [15]. It is a professional treatment planning toolkit developed by DKFZ for re-search and training. It is used to optimize the “prescription” of treatment of cancer tumoursusing photons, protons or carbon ions. Hence, students can appreciate the di ff erences ofthese modalities and optimally use them according to di ff erent cases. While it gives compa-rable results with commercial treatment planning software actually used for therapies, it islightweight, flexible and provides results quite fast.The data provided are a “water phantom” and computer tomography (CT) scans of headand liver tumour cases. matRAD presents the data in 3D, provides possibilities to rotate inter-actively and present slices in 2D projections. It provides graphical tools to select the volumesto be irradiated allowing for margins, and a particular exercise is planned to demonstrate theimportance of accurate alignment. matRAD also provides tools to select the critical organswhere the dose should be minimised. Once the volumes to maximise and minimise the doseare selected one can choose the type of radiation (photons, protons or carbon ions) and di ff er-ent angles for irradiation. For the optimisation, one can use constraints and define a minimumand / or maximum dose value. The visual result on the display, based on a colour scale, is veryintuitive to comprehend and easy to associate with the resulting histograms of the delivereddose to the target tumour and organs at risk to avoid. Students can see the photon radiationdepositing a larger dose in the tissues before the target tumour and penetrating healthy tissuesbehind the tumour. They can select di ff erent angles for irradiation to minimize the depositeddose in each trajectory while accumulating the required dose in the target point. The studentscan then witness the di ff erent properties of protons, and in particular of carbon ions, that, incontrast, deposit very little energy in the tissues before and practically none after the tumour.Figure 3 shows the PTMC application with the head tumour example.The accompanying lectures are related to particle interactions with matter, and with ra-diation in general spanning from its use in microwave ovens to discoveries studying cosmicradiation. The impact of accelerators becomes clear quoting some fifteen thousand used formedical applications, but also the need for further research and optimization. Imaging, diag-nostics, dosimetry, are a critical part of the treatment procedures where again the impact ofbreakthrough developments on detectors for physics experiments is clear. This hands-on ex-perience also makes clear the importance of computing and software developments and usualquestions bring the discussion on machine learning techniques and their possible applicationsfor these cases. Students taking part in the pilot session were impressed with the possibilityto perform a treatment planning like professionals and motivated to contribute to the furtherig. 3: Main window of the Particle Therapy Masterclass showing therapy planning for thehead tumour case.advancements of this multi-disciplinary field. Overall, the obvious need for properly trainedscientists was an unavoidable conclusion and take-home message.All the necessary material is available via the web page [16] which includes details forthe matRAD installation (on Windows, Linux and MacOS), di ff erent workflows together withthe associated demos and step-by-step presentations, instructions for tutors and moderatorsas well as lectures and animations. The International MasterClasses programme is currently undergoing substantial increase interms of number of experiments participating and available measurements. Moreover, withthe inclusion of the Particle Therapy MasterClass the scope of the programme extends nowbeyond fundamental research in particle physics.The ALICE MasterClass framework was redesigned and the three measurements are nowintegrated into one common framework, based on ROOT, as the experiment’s software. Themacro-based solution was replaced by compiled standalone applications for all three majoroperating systems (Windows, Linux, MacOS X) which are provided with easy to use in-stallers. In addition, the ROOT package was embedded in the framework making transparentits installation. Current works are focused on moving the whole framework into a web-basedsolution and a client-server architecture, while keeping the possibility to use ROOT-data filesand ROOT objects.The new Particle Therapy MasterClass extending the scope of the International Master-Classes programme to medical applications is prepared following the general rules of otherMasterClass measurements, providing a simplified tool based on the actual computer pro-gram for treatment planning. Data of liver and head tumour cases and a variety of beamchoice (photons, protons, carbon ions) allow for detailed analysis of possible treatment sce-narios. The first PTMC session within the IMC2020 was attended by 200 students in Mexicoand shows the big interest for measurements on applications. cknowledgements
The ALICE MasterClass is a part of the “MatFizChemPW” project which is supported bythe European Union through the European Social Fund under the Operational ProgrammeKnowledge Education Development (Poland).
References [1]
International Particle Physics Outreach Group , http: // ippog.org / , [Online; accessed 8-March-2020][2] International MasterClasses – Hands-on Particle Physics , https: // physicsmasterclasses.org / , [Online; accessed 8-March-2020][3] L. Evans, P. Bryant, JINST , S08001 (2008)[4] G.R. Dagenais, D.P. Leong, S. Rangarajan, F. Lanas, P. Lopez-Jaramillo, R. Gupta,R. Diaz, A. Avezum, G.B.F. Oliveira, A. Wielgosz et al., The Lancet , 785 (2020)[5] K. Aamodt et al. (ALICE), JINST , S08002 (2008)[6] I. Antcheva et al., Comput. Phys. Commun. , 2499 (2009)[7] Foka, Panagiota, Janik, Malgorzata, EPJ Web of Conferences , 00057 (2014)[8] ALICE MasterClass on nuclear modification factor , http: // / masterclass / , [Online; accessed 8-March-2020][9] ALICE MasterClass Webpage , https: // alice-masterclass.web.cern.ch / , [Online; accessed8-March-2020][10] New Masterclass for pupils on particle therapy , https: // / en / start / news / details / / / / masterclass_partikeltherapie0.html, [Online; accessed 8-March-2020][11] A.D. Jensen, M.W. Münter, J. Debus, The British Journal of Radiology , S35 (2011)[12] L. Badano, M. Benedikt, P.J. Bryant, M. Crescenti, P. Holy, A.T. Maier, M. Pullia,S. Rossi, P. Knaus (CERN-TERA Foundation-MedAustron Oncology-2000 Collabora-tion), Proton-Ion Medical Machine Study (PIMMS), 1 (1999), https://cds.cern.ch/record/385378 [13]
Deutsches Krebsforschungszentrum , , [Online; accessed 8-March-2020][14] H.P. Wieser, E. Cisternas, N. Wahl, S. Ulrich, A. Stadler, H. Mescher, L.R. Müller,T. Klinge, H. Gabrys, L. Burigo et al., Medical Physics , 2556 (2017)[15] MATLAB , , [Online; ac-cessed 8-March-2020][16] Particle Therapy MasterClass , https://indico.cern.ch/event/840212/https://indico.cern.ch/event/840212/