UHDpulse 2nd Stakeholder Meeting
Fyzikální ústav AV ČR, v. v. i. (FZÚ)
The UHDPulse 2nd Stakeholder's Meeting is hosted by ELI Beamlines. It is a fully in-person meeting.
Dates: 26-27 Jan 2023 at FZÚ (Fyzikální ústav AV ČR, v. v. i.)
Location: Na Slovance 1999/2, Prague 8, Czech Republic. The entrance to the conference is from the street "Pod Vodárenskou Věží"
We invite you to register as soon as possible as capacity is limited. For further information, you can contact anna.cimmino@eli-beams.eu
Disclaimer: This is an internal meeting of the EMPIR 18HLT04 project and not a scientific conference. Any results or information presented are not intended for publication, presentations, not scientific discussion without prior agreement from the EMPIR 18HLT04 project.
No cancellation charge applies if it occurs two weeks before the meeting (local time).
Alexandra Bourgouin
Alžběta Vosátková
Andreas Schüller
Anna Cimmino
Anna Subiel
Anne Klimpel
Celeste Fleta
Charles Fouillade
Claude Bailat
Cristina Oancea
Faustino Rodriguez
Felix Horst
Felix Riemer
Gianluca Verona Rinati
Jaroslav Šolc
Jiří Pivec
José Paz-Martín
Marco Marinelli
Matthias Gross
Miroslav Zboril
Pavel Špíšek
Peter Peier
Pia Kahle
Rafael Kranzer
Roberto Versaci
Sairos Safai
Sean McCallum
Sophie Heinrich
Séverine Rossomme
Thomas Kormoll
Tomas Cechak
Verdi Vanreusel
Veronika Olšovcová
Zina Čemusová
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Registration
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Opening Session
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1
Welcome and Opening RemarksSpeaker: Veronika Olšovcová (Fyzikální ústav AV ČR, v. v. i.)
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2
UHDpulse Project: Overview and Current StatusSpeaker: Andreas Schüller (PTB)
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1
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Work Package 1Convener: Dr Anna Subiel (National Physical Laboratory)
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4
Review of beam parameters in FLASH RT
Review of beam parameters in FLASH Radio Therapy
Speaker: Sophie Heinrich (Institut Curie) -
10:20
Coffee Break
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5
Primary standard for absorbed dose measurements in UHPDR high energy electron beams at the PTB facility
The first main task of PTB within the UHDpulse project was to establish reference UHPDR electron beam. In this aim, the PTB research accelerator has been optimised to generate two 20 MeV reference beams which have been characterised along with the development of a Monte Carlo beam model enabling a third beam set-up for a total dose per pulse range from 0.1 Gy to 16 Gy per pulse. The second main task of PTB was to establish the PTB water calorimeter as primary standard. In this aim, the calculation of the required correction factors has been carried on using thermal simulations and Monte Carlo simulations. Finally, the absorbed dose measurements using the PTB water calorimeter has been compared to the primary standard used at METAS, Fricke dosimetry, for validation purposes using mailed alanine dosimeters as transfer dosimeters with the collaboration of NRC.
Speaker: Alexandra Bourgouin (Physikalisch-Technische Bundesanstalt) -
6
Absolute Charge Measurement in UHDpulse electron beams
We will present our efforts to calibrate the METAS ICTs and the CHUV ACCT for ultra high dose per pulse electron beams using the PTB current generator. We will also show the appilcation of such a devices in the establishment of the Fricke primary and secondary standards
Speaker: Peter Peier (METAS) -
7
Primary standard calorimetry for UHDR proton beams
It has been shown that FLASH radiotherapy can significantly spare healthy tissues whilst still being at least as effective in curing cancer as radiotherapy at conventional dose rates. These properties promise reduced post-treatment complications, whilst improving patient access to proton beam radiotherapy and reducing costs. However, accurate dosimetry at UHDR is extremely complicated. The work presented in this talk will demonstrate measurements performed with a primary-standard proton calorimeter (PSPC) at the Cincinnati Proton Centre and outline derivation of the required correction factors needed to determine absolute dose for FLASH proton beam radiotherapy.
Speaker: Anna Subiel (National Physical Laboratory) -
8
Proof-of-principle calorimetry measurements for absolute dosimetry of laser-driven ions beams
The generation of charged particle beams to ultra-high pulse dose rates (UHPDR) have been proposed for use within future applications, although dosimetry of these beams has proven to be technically challenging. Calorimetry techniques provide an arguably ideal solution but their application is not trivial due to the quasi-instantaneous and inhomogeneous dose deposition patterns. A first of its kind proof-of-principle measurement of the absorbed dose of laser-driven proton beams using a modified small portable graphite calorimeter is reported. Through the use of the VULCAN-PW laser system at Rutherford Appleton Laboratory, ultra-high dose rate pulses were accelerated producing dose deliveries on the Gy level. The absorbed dose values measured from the calorimeter signal were compared with that obtained through radiochromic films. Electromagnetic pulse effects were assessed, showing no distortion on the measured signal. This investigation thus successfully demonstrates the application of calorimetry techniques as a tool for dosimetry of UHPDR beams.
Speaker: Sean McCallum (Queen's University Belfast)
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12:00
Lunch
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9
Welcoming Remarks from the Deputy Director of FZU - RNDr. Antonín Fejfar, CSc.Speaker: Dr Antonin Fejfar (Institute of Physic Academy of Sciences of the Czech Republic)
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Work Package 2Convener: Peter Peier (METAS)
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11
Secondary standards and relative dosimetry in UHPDR high energy electron beams at the PTB facility
Using the two reference UHPDR electron beams characterised at the PTB facility, it was possible to perform the characterisation of Alanine/ESR secondary standard dosimetry system and to conclude that no dose rate dependency of the response occurs in a dose per pulse range between 0.1 Gy to 6 Gy per pulse. The second secondary standard to be tested was commercially available ionisation chambers. Seven commercially available chamber types were tested in the reference UHPDR electron beam to determine the charge collection efficiency. As 22 chambers were tested, it was possible to determine the inter-type and the intra-type variations. To evaluate non-commercially available dosimeters, but with alleged dose rate independency, a graphite probe-type calorimeter, namely Aerrow, was tested in the reference beam at the PTB facility.
Speaker: Alexandra Bourgouin (Physikalisch-Technische Bundesanstalt) -
12
flashDiamond – Review and Outlook
This contribution contains a review and outlook on the work with diamond detectors, which was carried out in the framework of the UHDpulse project. Using the commercially available microDiamond detector and modifications, the critical parameters for linearity under ultra-high dose per pulse conditions were determined and optimized. The optimized detector - flashDiamond - was validated on four different potentially FLASH-capable accelerator systems with electron beams. The linearity is given up to a dose per pulse of at least 10 Gy at a pulse length of 3 µs. In addition, three-dimensional dose distributions and output factors were successfully measured. The flashDiamond type 60025 is commercialized as a laboratory device for research purposes and thus available for further users and a variety of dosimetric applications.
Speaker: Rafael Kranzer (PTW-Freiburg) -
13
Diamond detectors for instantaneous dose rate measurements in UH-DR and UH-DPP beams
A review on the use of diamond-based detector for time-resolved measurements under UH-DR and UH-DPP beams will be presented. In particular, the microDiamond and the flashDiamond detectors were utilized for dose and instantaneous dose rate measurements in UH-DR scanned ion beams and UH-DPP electron beams. The developed dosimetric systems were found to be suitable tools for the acquisition of instantaneous dose rate traces, also allowing for a comprehensive dosimetric characterization of radiation beams for FLASH radiotherapy applications.
Speaker: Prof. Gianluca Verona Rinati (University of "Rome Tor Vergata", Rome, Italy) -
14
Volume recombination in parallel-plate ionization chambers
A detailed numerical simulation of the charge carrier transport inside a parallel plate ionization chamber (PPIC) was developed in UHDPulse. This methodology allows the study of the contributions of ion-ion, electron-ion, electric field perturbation, beam time structure and influence magnitudes to the recombination effect [1,2].
The simulation has been commissioned against an extensive amount of experimental data showing satisfactory results. Based on the simulation results, it was concluded that the distance between electrodes has the major impact mitigating the volume recombination losses [3]. Various ultra-thin ionization chambers with 0.25 mm distance between electrodes were built and tested in different ultra-high dose rate electron beams [4].
References
[1] Romano et al. Med Phys. 49: 4912- 4932 (2022)\
[2] Paz-Martin J. et al. Physica Medica 103, pp. 147-156 (2022)\
[3] Kranzer R. et al. Physica Medica 104, pp. 10-17 (2022)\
[4] Gomez F. et al. Medical Physics 49(7), pp. 4705-4714 (2022)
Speaker: Faustino Gomez (Universidad de Santiago) -
14:50
Coffee Break
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15
The inadequacy of the established analytical ion recombination models for ionization chamber dosimetry at conventional dose rates
The code of practice (TRS398 and TG51) for the determination of the absorbed dose to water recommend the use of the two-voltage method (TVM) for the calculation of the ion recombination correction factor, which is based on the early Boag theory and do not take into account the contribution of free electrons to the ionization chamber signal. Later, Boag and contemporaries developed three additional models that exhibit inconsistency even in the conventional dose per pulse regime.
A detailed numerical simulation of the charge carrier transport inside a parallel plate ionization chamber (PPIC) was developed in order to obtain the dynamical response of a PPIC.
Experimental data on saturation factor obtained for two Advanced Markus and PPC05 chambers at the 20 MeV PTB MELAF electron beam has been successfully compared with the numerical simulation providing evidence of the limited validity of the TVM.
Speaker: José Paz-Martín (University of Santiago de Compostela) -
16
Ionisation Chamber Dosimetry in Ultra-Short Pulsed High Dose-Rate Very High Energy Electron (VHEE) Beams
High dose-rate radiotherapy has been shown to increase the differential response between healthy and tumour tissue. Moreover, Very High Energy Electrons (VHEEs) provide more favourable dose distributions than conventional radiotherapy electron and photon beams. Plane-parallel ionisation chambers are the recommended secondary standard systems for clinical reference dosimetry of electrons, therefore chamber response to these high energy and high dose-per-pulse beams must be well understood. Graphite calorimeter, developed and realized at NPL, has been employed to measure the dose delivered from a 200 MeV pulsed electron beam. This was compared to the charge measurements of a plane-parallel ionisation chamber to determine the absolute collection efficiency and infer the ion recombination factor.
Speaker: Anna Subiel (National Physical Laboratory)
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Social Dinner
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Work Package 3Convener: Claude Bailat (CHUV)
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18
FLASH experiments at the Dresden platform for high dose rate radiobiology
The Dresden platform for high dose rate radiobiology consists of the superconducting research electron linear accelerator ELBE, two research beam lines at the Dresden University Proton Therapy facility and the DRACO laser accelerator. Recent radiobiological FLASH experiments using zebrafish embryos performed in these facilities will be presented. A focus will be laid on instrumentation and dosimetry issues related to beam application at ultra-high dose rate and how they are dealt with.
Speaker: Felix Horst (OncoRay Dresden) -
19
Development of innovative silicon carbide detectors for radiation detection and dosimetry
In this talk I will present the many potential applications of SiC radiation detectors for demanding radiation environments and I will give an overview of the recent technological developments at Instituto de Microelectrónica de Barcelona (CNM-CSIC) in Spain. Finally I will show the results of the SiC diodes for FLASH dosimetry developed by CNM in the framework of the EMPIR-UHDPulse project.
Speaker: Celeste Fleta (Instituto de Microelectronica de Barcelona, IMB-CNM (CSIC)) -
20
UHDR dosimetry in Antwerp
We tested micro-diamonds (collaboration with the University of Roma tor Vergata) and ultra-thin ionization chambers (collaboration with the university of Santiago de Compostela), and investigated optically stimulated luminescence (OSL) sheets, point scintillators and a 2D scintillating dosimetry system (in collaboration with SCK-CEN and Agfa).
The ElectronFlash allows systematic variation of the number of pulses, pulse repetition frequency (PRF) and pulse length.
All tested dosimeters showed to be promising, but optimization is needed to overcome their limitations. The prototype micro-diamond for UHDR electron beams, currently distributed by PTW Freiburg, requires a dedicated box to reduce the instantaneous current presented to the electrometer. The OSL sheets with lowest sensitivity showed an instantaneous dose rate dependence, and the point scintillators and 2D scintillating system were limited by their scintillating decay.
The research on UHDR electron dosimetry in Antwerp has led to promising results using a large variety of dosimetric tools.
Speaker: Verdi Vanreusel (University of Antwerp / SCK CEN)
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Poster Session: Coffee and Poster Session
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Stakeholder/External Contributions
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21
First dosimetry tests at PITZ
The Photo Injector Test facility at DESY in Zeuthen (PITZ) can provide unique beam parameters regarding delivered dose and dose rate. With an average dose rate of up to 1E7 Gy/s and peak dose rates of up to 4E13 Gy/s, PITZ is fully capable of UHDR irradiation which should allow FLASH radiation therapy.
A completely new beamline exclusively for FLASH RT and biology experiments was built. One goal is to develop and test detectors which cover the whole range of dose rates. Additionally, there is the possibility for external users to test their detectors, bring their biological samples for irradiation and do joint experiments at PITZ!
First dosimetry experiments using Gafchromic films were done in air and in water. Dose rate linearity and limit tests of the films will be presented. Beam parameters like beam profile, dose depth profile in water, homogeneity and dark current will be shown.Speaker: Felix Riemer (DESY Zeuthen)
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21
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Work Package 4Conveners: Cristina Oancea (Advacam), Dr Cristina Oancea (ADVACAM), Jiri Pivec (ADVACAM)
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23
Characterization of out-of-field of electron and proton beams using Timepix3 detectors
Stray radiation produced by ultra-high dose-rates (UHDR) electron and proton beams is characterized using a MiniPIX Timepix3 detector equipped with a silicon sensor and integrated readout electronics. The chip-sensor assembly and chipboard on water-equivalent backing were detached and immersed in the water phantom. The deposited energy, particle flux, dose rate, and linear energy transfer (LET(Si)) spectra were measured in the silicon sensor at different positions inside the water. A good agreement was found between measured and simulated absorbed doses.
Speaker: Dr Cristina Oancea (ADVACAM)
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GROUP PHOTO!
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12:10
Lunch
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Work Package 4Conveners: Dr Cristina Oancea (ADVACAM), Cristina Oancea (Advacam), Jiri Pivec (ADVACAM)
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24
Characterization of out-of-field of electron beams using Luminescence DosimetersSpeaker: Dr Anna Cimmino (Fyzikální ústav AV ČR, v. v. i.)
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25
Bonner sphere spectrometers for neutron stray radiation field characterization
An overview of developments in Bonner sphere neutron spectrometry for neutron stray radiation field characterization in EMPIR project UHDpulse.
Speaker: Miroslav Zboril (PTB)
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24
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Work Package 5Convener: Šolc Jaroslav (Czech Metrology Institute)
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26
WP5 overview
Status of the WP5 Creating Impact
Speaker: Šolc Jaroslav (Czech Metrology Institute)
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26
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Work Package 6 and Closing RemarksConvener: Andreas Schüller (PTB)
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27
UHDpulse Project: Overview and Current Status
Dosimetry for FLASH radiotherapy, VHEE radiotherapy as well as for laser driven beams cause significant metrological challenges due to the ultra-high dose rates and pulsed structure of these beams, in particular for real time measurements with active dosimeters. UHDpulse developed metrological tools needed for reliable real-time absorbed dose measurements of electron and proton beams with ultra-high dose rate and ultra-high dose per pulse. Within UHDpulse, primary and secondary absorbed dose standards and reference dosimetry methods are developed, the responses of available state-of-the-art detector systems are characterised, novel and custom-built active dosimetric systems and beam monitoring systems are designed, and methods for relative dosimetry and for the characterization of stray radiation are investigated.
A brief overview of the achievements of the involved institutions within the framework of UHDpulse will be given as introduction of the meeting.
Speaker: Andreas Schüller (PTB)
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27
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15:00
Goodbye Coffee Break
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