1. NINS3 and Radiation metrology for advanced medical applications
Teemu Siiskonen
Radiation and Nuclear Safety Authority
Helsinki, Finland

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

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

4. 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

5. 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

6. 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)

7. 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
Gamma ray emission tomography can detect a single replaced fuel rod
Schematic view of PWR fuel assembly (Mitsubishi Nuclear F

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

9. 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

10. 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)

11. 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

12. 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)

13. 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

14. 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

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

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

17. 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!