NINS3 and Radiation metrology for advanced medical applications Teemu Siiskonen Radiation and Nuclear Safety Authority Helsinki, Finland Teemu.siiskonen@stuk.fi 19.5.2017

Topics What is STUK? NINS3: Novel instrumentation for Nuclear Safety, Security and Safeguards Radiation Metrology for Applications: Real-time dosimetry for external beam radiotherapy

STUK – Finnish Radiation and Nuclear Safety Authority Mission: Protecting people, society, environment, and future generations from harmful effects of radiation

Three roles of STUK Regulatory body: use of nuclear reactors, nuclear waste, use of radiation, environmental monitoring, non-ionising radiation Expert organisation: national emergency prepardness, training, services Research and development: reduction of significant health risks, reliability of measurements, emergency prepardness – collaboration with universities

NINS3 project Novel instrumentation for Nuclear Safety, Security and Safeguards Funding (Tekes) via the FiDiPro program, 2015 – 2018 Project partners: Helsinki Institute of Physics (HIP) (Project lead Prof Peter Dendooven) Tampere University of Technology (TUT) University of Jyväskylä (JYU) the Finnish Radiation and Nuclear Safety Authority STUK Institute of Transuranium Elements (JRC-ITU) Budapest University of Technology and Economics (BME) and a consortium of companies in Finland

Research topics of NINS3 Passive tomography of spent nuclear fuel Alpha radiation and threat detection from a distance using UV emission Active neutron interrogation of unknown objects Research to business (R2B)

Verification of spent nuclear fuel Develop methods to test for partial defects in fuel assembly Detect the diversion of part of the fuel to nondeclared purposes Current verification tools have limited sensitivity IAEA policy: need high detection probability www.world-nuclear.org Gamma ray emission tomography can detect a single replaced fuel rod Schematic view of PWR fuel assembly (Mitsubishi Nuclear F

PGET images (preliminary) Image reconstruction optimization ongoing at IAEA and HIP PGET: Passive Gamma Ray Emission Tomograph

Future safeguards activities Final disposal of spent nuclear fuel: a suitable fuel inspection device is needed when storage in Finland starts in 2023 HIP is fully participating in: Geological Repository: Safeguards and Security R&D (GOSSER) STUK and HIP will plan together how to continue safeguards R&D for geological repositories beyond 2018 www.posiva.fi/en/final_disposal

Active neutron interrogation of unknown objects Measure/image neutron-induced isotope-specific gamma radiation to quantify unknown objects Unknown objects are e.g. (suspected) explosives and chemical weapons Geant4 Monte Carlo simulations used for n emission simulations and detector response for neutrons Optimization: Consider both neutron source and detector specifications Fast neutrons (E > 1 MeV)

Medical use of radiation and associated metrology New means are needed to ensure patient safety especially in external small, conformal beam radiotherapy Measurement methods are not fully mature and reliable Serious accidents have happened due to inappropriate measurements In external beam radiotherapy the dosimetry is a three-step process Calibration of the user detector (ion chamber) at laboratory (SSDL) Measurement of linac beam properties at the clinic in standard conditions Plan the treatment and verify the dose delivery to patient All steps are time consuming (beam profiles, depth doses), need new position sensitive (2D) detectors, stack these or scan Spatial resolution ~ 0.5 mm or better, linear dose response (e, g, p) Analysis software, real-time 3D dose distributions in water Absolute dosimetry with ion chamber or alanine

Accuracy of the treatment Full, independent characterisation of the beam Standard level absolute dosimetry in photon and proton beams Especially small beam geometry Relative, real-time 3D dosimetry with good spatial resolution Must be suitable for use at clinics, transportable New nuclear data (e.g. stopping powers)

Technical challenges to be tackled High dose rates, dose linearity and high spatial resolution required Photon dose rates up to several hundreds of Gy per hour, possible neutron contamination in beam. Measurements in water! Read-out chips is the main challenge in hardware  Consider the ROCs from CMS Si detectors Array of detectors is needed, challenges for the data processing, optoelectronics and software  experience from previous CERN experiments is valuable! Feasibility study of semiconductor, scintillation and optical detectors started

Si 2D detector at STUK SSDL beam test Detector response in 60Co beam, dose rates up to 60 Gy/h Accurate reference dosimetry available (SSDL) Spectral information also available pixel by pixel

Scintillation visualization chamber at SSDL 15 Gy/h 30 Gy/h 45 Gy/h GAGG(Ce) and GOS(Tb) scintillators

Scintillation MULTIPIX detector at SSDL GAGG(Ce) crystal, Si PM

Summary The NINS3 and the Metrology projects aim at improved safety, security and safeguards in radiation-related applications Internationally identified high-priority topics Industrial partners, R2B point-of-view Experience gained in HEP detector development and signal processing is crucial Projects bring together established universities, research centers, authorities and companies to ensure efficient dissemination of the results Thank you!