metrology and accelerator applications graeme taylor neutron metrology group national physical...

Metrology and Accelerator Applications

Graeme Taylor

Neutron Metrology GroupNational Physical Laboratory, Teddington, UK

Applications of Particle Accelerators in Europe

18-19 June 2015

Royal Academy of Engineering

Metrology and Accelerator Applications

Graeme Taylor

Neutron Metrology GroupNational Physical Laboratory, Teddington, UK

Applications of Particle Accelerators in Europe

18-19 June 2015

Royal Academy of Engineering

Neutron

Scope

Brief overview of NPL Overview of Neutron Metrology

Accelerator-based facilities Introduction to BIPM (comparability of measurements)

Ionising radiation Monoenergetic neutron providers Current / future plans for accelerators at European NMIs 1 slide on proton and ion beam dosimetry at NPL 1 slide on the 2011 EMRP bid for HE Neutron Reference

Fields

The UKNational Physical Laboratory

Science divisions of theNational Physical Laboratory

Acoustics & Ionising Radiation

Analytical Science

Engineering Measurement

Materials Time, Quantum & Electromagnetics

Acoustics

Radiation Dosimetry

Radioactivity

Neutron Metrology

Environmental Measurements

Nanoanalysis

Gas Metrology & Trace Analysis

Biotechnology

Engineering Measurement

Services

Temperature & Humidity

Mass & Dimensional

Optical Measurement

Advanced Engineered Materials

Thermal & Electrochemical

Nano & Multifunctional

Materials

Materials Processing & Performance

Electronics & Modelling

Communication Technologies

Quantum Detection

Quantum Frequency Standards

Time & Security

Electrical & Instrumentation

Electromagnetics

Aims and capabilities

Role: Ensure measurements in the UK are consistentand to the required accuracy

The Neutron Metrology Group, NMG, provides: Characterised neutron fields

Traceable calibrations Type test facilities Neutron spectrometry capabilities (field mmts) Research into dosimetry techniques

Chadwick building: home of theNeutron Metrology Group

Two FacilitiesNeutron emission rate

measurement facilityLow scatter irradiation

facility

InstrumentationField spectrometersMicrodosimetersArea and personal

dosemeters

Main experimental area

Low Scatter Facility:18 m wide x18 m high x26 m long

Used for:Monoenergetics‘Multienergy’Simulated fieldsIsotopic sources

Additional facility:Thermal Pile

Van de Graaff accelerator

3.5 MV accelerator

Proton & deuteron ion sources

Energy width ~3 keV

Beam currents:< 20 uA (LSA) ~80 uA (pile)

Installed mid-1960s (modular design)

Time-of-flight capability* *On a good day!

VdG control desk

Monoenergetic neutrons(ISO) energies and intensities

Neutron Energy(MeV)

ReactionMaximum rates at 1 m

Fluence(cm-2 s-1)

H*(10)(μSv h-1)

0.027 45Sc(p,n)45Ti 8 0.6

0.070 7Li(p,n)7Be 500 100

0.144 7Li(p,n)7Be 1000 450

0.250 7Li(p,n)7Be 600 440

0.565 7Li(p,n)7Be 1600 2000

1.2 T(p,n)3He 200 300

2.5 T(p,n)3He 300 500

5.0 D(d,n)3He 600 870

17.0 T(d,n)4He 500 1000

‘Multienergy’ facility

100 1000

0.0

2.0x10-5

4.0x10-5

6.0x10-5

8.0x10-5

1.0x10-4

1.2x10-4

Fluence response function

Flu

ence

resp

onse

(tr

ack

s per

neutr

on)

Neutron energy (keV)

Multi-energy Field A 101 keV - 250 keV Multi-energy Field B 336 keV - 565 keV Multi-energy Field C 561 keV - 1200 keV Monoenergetic 2.5 MeV and 5.0 MeV

Fluence response function of PADC personal neutron dosimeter

Thermal pile

Graphite block: 2.8 m long x 1.4 m wide x 1.6 m high

Thermal column field

Significant fast neutron component

2nd Irradiation with Cd cover required

Fluence rates ~4 × 104 cm-2 s-1

Beam area ~ 30 cm diameter

Components: Fast Thermal

Fluence 19% 81%

H*(10) 69% 31%

H*(10) rate of thermal field: ~1 mSv h-1

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

10-3 10-2 10-1 100 101 102 103 104 105 106 107 108

1E-3

0.01

0.1

1

Gro

up fl

uenc

e pe

r fis

sion

cou

nter

pul

se (

cm-2

)

Linear

Neutron energy (eV)

Log

NPL simulated workplace field facility

‘Thick’ Al / Li alloy

Moderation: 40 cm dia. sphere of D2O

Max. rates at 150 cm:Fluence: 2000 cm-2 s-1

H*(10): 180 μSv h-1

Testing the Rospec in thesimulated workplace field

10-3 10-2 10-1 100 101 102 103 104 105 106 107

0.0

5.0x105

1.0x106

1.5x106

2.0x106

2.5x106

3.0x106

E.

(E)

(cm

-2)

Neutron energy (eV)

Comparison of NPL and Rospec spectra for 3.0 MeV proton bombardment

Rospec TNS & NPL.opj

NPL

Rospec

Fluence(cm-2)

H*(10)(Sv)

NPL 1.30 x107 290

Rospec 2.01 x107 328

Ros/NPL 1.55 1.13

Global providers ofmonoenergetic neutrons

IRMM

VNIIM

Looking to the future (accelerator-based neutron metrology in Europe)

PTB Germany

Approval for new Tandetron 2 MV accelerator granted

Under construction by HVEE in Amersfoort/Netherlands

Expected delivery Q2-Q3 2016 IRSN France

Already have a 2 MV Tandetron from HVEE

Off-line 2014 – 2016 for installation of 2nd beam line for microbeam facility

NPL

Discussions re: accelerator replacement at early stage

Proton and ion beam dosimetry at NPL development of a primary standard for protons and ions

based on a portable graphite calorimeter improved measurements of the mean energy required to

produce an ion pair in air for ionisation chamber dosimetry in proton and ion beams

improved measurement and simulation using Monte Carlo methods of ionisation chamber perturbation factors;

characterisation of energy dependent absorbed dose response of relative dosimeters: alanine, radiochromic film

Improved dose conversion from different materials to water develop SQUID-based micro-calorimeter to measure ion

beam microdosimetric spectra to underpin the definition of more biologically relevant quantity for radiotherapy.

2011 EMRP bid for HE Neutron Reference Fields (Failed!)

Secondary radiation produced during ion (proton / carbon) therapy consists primarily of high-energy neutrons

Characterization and calibration of dosemeters used in such fields require traceable neutron reference fields in the energy ranges under consideration (up to “a few 100 MeV”)

No metrological facilities for this purpose in Europe Several proton / carbon ion therapy centres already in

operation and more will start treatment in next few years There is a need to provide metrological infrastructure for

such reference fields and provide them to stakeholders Proposed to develop such reference fields at existing proton

therapy facilities.

The National Measurement System is the UK’s national infrastructure of measurement

Laboratories, which deliver world-class measurement science and technology through four

National Measurement Institutes (NMIs): LGC, NPL the National Physical Laboratory, TUV NEL

The former National Engineering Laboratory, and the National Measurement Office (NMO).

The National Measurement System delivers world-class measurement science & technology through these organisations

Program of Work 2016-2019 of theIonizing Radiation Department

José M. Los ArcosCCRI Executive Secretary

IR Department Director

CCRI(III)BIPM, 4-6 March 2015

CCRI/15-18

www.bipm.orgBureau International des Poids et Mesures

PoW 2016-2019: IR priority activities

Aim of Ionizing radiation activities• to provide Member States with metrological support to provide confidence in the

services that the NMIs offer to their users, based on a well-defined and stable set of international reference facilities to compare and establish the equivalence or traceability of the national standards for dosimetry and radionuclide activity in health applications (radiotherapy, nuclear medicine, radiodiagnostic), nuclear industry, environmental survey and related activities.


PoW 2016-2019: Dosimetry activities

IR-A1.3 High-energy dosimetry (accelerator dosimetry)

Target: the BIPM.RI(I)-K6 on-going comparisons of absorbed dose to water for high-energy photon beams, using the transportable BIPM graphite calorimeter on-site at the NMIs.

Scope: establishing and maintaining the long-term equivalence and traceability of absorbed dose for photons and eventual extension to electrons (see IR-A1-5 in alternative projects) in high-energy beams now used in the vast majority of radiotherapy applications.

Participant NMIs: 16

1) Maintaining the transportable photon calorimeter standard to provide robust traceability for absorbed dose through on-site comparisons and characterizations of national standards,

2) Providing 4-6 BIPM.RI(I)-K6 comparisons on-site at the NMIs,

3) Continued study of long-term optimal scenario for a sustainable maintenance of BIPM.RI(I)-K6 comparisons, using the BIPM graphite calorimeter standard.

IR-A1.4 Brachytherapy

Target: the BIPM.RI(I)-K8 on-going comparisons of reference air kerma using two transportable transfer instruments on-site at the NMIs.

Scope: establishing and maintaining the long-term equivalence of reference air kerma for HDR 192Ir sources, and eventual extension to LDR 125I sources, worldwide used in brachytherapy applications.


1) Maintaining the BIPM transfer standards (thimble and well-type chambers) for brachytherapy.

2) Providing 4 BIPM.RI(I)-K8 on-site comparisons for NMIs of reference air kerma for HDR 192Ir sources, as adopted by the CCRI.

3) Study on the convenience and feasibility of future development of a primary standard. Proposal at CCRI-2017.

www.bipm.org

Program of Work 2016-2019 of theIonizing Radiation Department

José M. Los ArcosCCRI Executive Secretary

IR Department Director

CCRI(III)BIPM, 4-6 March 2015

CCRI/15-18

www.bipm.org

Index

o Terms of reference• PoW 2016-2019• Mission and Role of the BIPM• BIPM objectives

o IR priority activities• Dosimetry • Radionuclide measurements• International coordination

o Alternative activities


Terms of Reference

• “Programme of work and budget of the BIPM for the four years 2016-2019” CIPM, 2015 • Pending of publication by the CIPM


PoW 2016-2019: Mission and Role of the BIPM

The mission of the BIPM is:

• to ensure and promote the global comparability of measurements, including providing a coherent international system of units for:

- Scientific discovery and innovation,- Industrial manufacturing and international trade,- Sustaining the quality of life and the global environment.

The unique role of the BIPM is based on its international and impartial character enabling it:

• To coordinate the realization and improvement of the world wide measurement ‑system to ensure it delivers accurate and comparable measurement results.

• To undertake selected scientific and technical activities that are more efficiently carried out in its own laboratories on behalf of Member States.

• To promote the importance of metrology to science, industry and society, in particular through collaboration with other intergovernmental organizations and international bodies and in international forums.


PoW 2016-2019: The objectives of the BIPM BIPM objectives:

• To establish and maintain appropriate reference standards for use as the basis of a limited number of key international comparisons at the highest level.

• To coordinate international comparisons of national measurement standards through the Consultative Committees of the CIPM; taking the role of coordinating laboratory for selected comparisons of the highest priority and undertaking the scientific work necessary to enable this to be done.

• To provide selected calibrations for Member States.

• To coordinate activities between the NMIs of Member States, such as through the CIPM MRA, and to provide technical services to support them.

• To liaise as required with relevant intergovernmental organizations and other international bodies both directly and through joint committees.

• To organize scientific meetings to identify future developments in the world-wide measurement system required to meet existing and future measurement needs in industry, science and society.

• To inform, through publications and meetings, the science community, the wider scientific public and decision makers on matters related to metrology and its benefits.


PoW 2016-2019: IR priority activities

Aim of Ionizing radiation activities• to provide Member States with metrological support to provide confidence in the

services that the NMIs offer to their users, based on a well-defined and stable set of international reference facilities to compare and establish the equivalence or traceability of the national standards for dosimetry and radionuclide activity in health applications (radiotherapy, nuclear medicine, radiodiagnostic), nuclear industry, environmental survey and related activities.



Project Code Project Name Deliverables

IR-A1.1 X-ray standards dosimetry

Target: the BIPM.RI(I)-K2,-K3,-K7 on-going comparisons of air kerma or absorbed dose to water for low-, medium-energy and mammography, using the high-stability BIPM facilities.

Scope: establishing and maintaining the long-term equivalence or traceability of NMIs for nearly 20 x-ray radiation qualities adopted by the CCRI and widely used in radiotherapy and radiodiagnostics.


1) Maintaining the BIPM primary standards for:- air kerma in low- (5 qualities) and medium-energy (4 qualities) x-rays,- absorbed-dose to water in medium-energy x-rays developed in 2013-

2015 (4 qualities),- air kerma for mammography (4 qualities).

2) Providing 16 comparisons (BIPM.RI(I)-K2, -K3, -K7) for NMIs that need to update their results in the KCDB,

3) Calibration and characterization of 16 NMIs standards for x-rays, on request.

4) Replacement of HV generator for low-energy x-rays, in 2016

IR-A1.2 -ray standards dosimetry

Target: the BIPM.RI(I)-K1,-K4,-K5 and -K6 on-going comparisons of air kerma and/or absorbed dose to water for 60Co and 137Cs, using the high-stability BIPM facilities.

Scope: establishing and maintaining the long-term equivalence or traceability of NMIs for 60Co and 137Cs beams, widely used at radiotherapy and/or radioprotection levels, and serving as reference for the calorimetric measurements in high-energy photon beams (medical accelerators).


1) Maintaining the BIPM primary standards for:- air kerma in 60Co and 137Cs beams for radiotherapy and

radioprotection (BIPM.RI(I)-K1, K5),- absorbed dose to water in 60Co beams (radiotherapy,

BIPM.RI(I)-K4), - providing reference to the graphite calorimeter standard for

absorbed dose to water in high-energy beams (BIPM.RI(I)-K6).

2) Providing 20 comparisons (-K1, -K4, -K5) for NMIs that need to update their results in the KCDB.

3) Characterization and calibration of 40 national standards (on request).

4) Replacement of 60Co source in 2017.

IR-A1 Dosimetry Program for international equivalence of measurements in the Health field: radiotherapy, radiodiagnostics and radioprotection



IR-A1.3 High-energy dosimetry (accelerator dosimetry)

Target: the BIPM.RI(I)-K6 on-going comparisons of absorbed dose to water for high-energy photon beams, using the transportable BIPM graphite calorimeter on-site at the NMIs.

Scope: establishing and maintaining the long-term equivalence and traceability of absorbed dose for photons and eventual extension to electrons (see IR-A1-5 in alternative projects) in high-energy beams now used in the vast majority of radiotherapy applications.


1) Maintaining the transportable photon calorimeter standard to provide robust traceability for absorbed dose through on-site comparisons and characterizations of national standards,

2) Providing 4-6 BIPM.RI(I)-K6 comparisons on-site at the NMIs,

3) Continued study of long-term optimal scenario for a sustainable maintenance of BIPM.RI(I)-K6 comparisons, using the BIPM graphite calorimeter standard.

IR-A1.4 Brachytherapy

Target: the BIPM.RI(I)-K8 on-going comparisons of reference air kerma using two transportable transfer instruments on-site at the NMIs.

Scope: establishing and maintaining the long-term equivalence of reference air kerma for HDR 192Ir sources, and eventual extension to LDR 125I sources, worldwide used in brachytherapy applications.


1) Maintaining the BIPM transfer standards (thimble and well-type chambers) for brachytherapy.

2) Providing 4 BIPM.RI(I)-K8 on-site comparisons for NMIs of reference air kerma for HDR 192Ir sources, as adopted by the CCRI.

3) Study on the convenience and feasibility of future development of a primary standard. Proposal at CCRI-2017.


PoW 2016-2019: Radionuclide activities


IR-A2.1 International Reference System (SIR) for emitters

Target: the BIPM.RI(II)-K1 on-going comparisons of activity of solutions of -ray emitting radionuclides, using high-stability well-type ionization chambers and 226Ra sources.

Scope: establishing and maintaining the equivalence for more than 60 different radionuclides widely used in nuclear medicine or appearing in the nuclear cycle and environmental monitoring.


1) Maintenance and development of SIR facility for emitters future core comparisons

2) 40 BIPM.RI (II) – K1 bilateral ‘on demand’ comparisons as part of, covering (at least):

C-11 F-18 Na-22 Na-24 Sc-46 Sc-47 Cr-51 Mn-54 Mn-56 Co-56 Co-57 Co-58 Co-60 Fe-59 Cu-64 Zn-65 Ga-67 Se-75 Kr-85 Sr-85 Y-88 Nb-95 Mo-99 Tc-99m Ru-103 Ru-106 Cd-109 Ag-110m Ag-111 In-111 Sn-113 I-123 Sb-124 Sb-125 I-125 I-131 Ba-133 Xe-133 Cs-134 Cs-137 Ce-139 Ba-140 Ce-141 Ce-144

Eu-152 Gd-153 Sm-153 Eu-154 Eu-155 Ho-166m Yb-169 Lu-177 Ta-182Re-186 Ir-192 Au-195 Tl-201 Hg-203 Pb-203 B i-207 Rn-222 Th-228 Np-237 Am-241 Am-243.

3) Reduction of the total number of comparisons through further development of the Measurements Method Matrix (MMM)

IR-A2.2 International Reference System (SIR) for pure β emitters

Target: the BIPM.RI(II)-K1 on-going comparisons of activity of solutions of pure β emitters, using liquid-scintillation counting methods.

Scope: establishment of equivalence for approximately 15 different radionuclides widely used in nuclear medicine, nuclear cycle and environmental monitoring.


1) Operation, maintenance and development of SIR facility for β emitters, implemented in 2013-2015, for future core comparisons

2) 20 BIPM.RI (II) – K1 bilateral comparisons covering (on demand): 3H, 14C, 32P, 55Fe, 63Ni, 89Sr, 90Sr/Y, 99Tc, 147Pm, 204Tl and other radionuclides demanded by NMIs.

3) Reduction of current heavy-logistics K2 comparisons to a minimum


IR-A2 Radionuclides Program for international equivalence of measurements in the health, environmental and industrial fields: nuclear medicine, radiodiagnostics, PET nuclides, radiotherapy, monitoring contamination of food or environment and safe nuclear activities.



IR-A2.3 Extension of SIR to α emitters

Target: implementation of methods for extending to emitters the BIPM.RI(II)-K1 on-going comparisons of activity of solutions of radionuclides.

Scope: establishment of equivalence for about 10 radionuclides of interest in the nuclear cycle, nuclear medicine, radiotherapy and environmental survey.


1) Development and Implementation of liquid scintillation methods or -particle counting using defined solid angle detectors.

2) 10 BIPM.RI (II) – K1 bilateral comparisons, covering (on demand): 241Am, 223Ra, 211At, 238Pu, 210Po and other radionuclides demanded by NMIs.

3) This will allow to complete (with IR-A2.1 and IR-A2.2) the frame for the most common α- , β- and -emitters

4) Reduction of the total number of comparisons through further development of the Measurement Methods Matrix

IR-A2.4 International reference facility for comparison of short-lived -emitting radionuclidesTarget: the BIPM.RI(II)-K4 on-site (at NMIs) on-going comparisons of short-lived radionuclides, using the transportable transfer instrument (SIRTI).Scope: establishment of equivalence for about 10 short-lived -emitting radionuclides of interest in nuclear medicine, PET, molecular imaging. Participant NMIs: 15

1) Maintenance and development of the SIR Transfer Instrument for on-site comparisons and extension to new radionuclides.

2) 8 BIPM.RI (II) – K4 bilateral comparisons covering (on demand): 99mTc, 18F, 64Cu, 11C, 68Ga, 211At, 56Mn and other radionuclides demanded by NMIs.


IR-A2.5 Reference instruments for primary measurements

Target: provision of new SIR entries for improvement of KCRVs not well established, applying and developing technical skills of staff for efficient comparisons coordination.

Scope: the KCRVs improvements for about 15 radionuclides as support to traceability/equivalence of radionuclide comparisons.Participant NMIs: 15

1) Maintenance and further development of 4- (anti)coincidence counting and TDCR LSC systems.

2) Organization of 1 CCRI comparison, for 109Cd, and participation in 2 CCRI comparisons according to the Rolling Plan and the MMM table.

3) Establish missing KCRVs for 47Sc, 68Ge, 111Ag, 140Ba, 155Eu,195Au and improve KCRVs for 24Na, 56Co, 123I, 124Sb, 125Sb,153Sm, 154Eu, 166mHo, 177Lu, as priorities.



IR-A2.6 Establishment of operational capability for low-level activity measurements of and emittersTarget: to complete the capability of low-level activity measurements for and emitters.Scope: support to CCRI comparisons on environmental and reference materials programs for international cooperation.Participant NMIs: 12

1) Acquisition, Monte Carlo simulation and setup of a 4- NaI(Tl) well-type detector for emitters.

2) Operational use of the existing Quantulus 1220 LSC spectrometer for emitters.

3) Participation/organization of 1 CCRI comparison on low-level measurements of contaminated materials

IR-A2.7 Development of physical backup to SIR 226Ra sourcesTarget: prevention of long-term obsolescence of 226Ra sources (IR-A2.1), by implementing as replacement an electronic absolute current source.

Scope: enhanced robustness of SIR in the long-term, as additional safeguard to the equivalence of more than 60 emitters widely used in nuclear medicine or appearing in the nuclear cycle and environmental monitoring.Participant (related) NMIs: 25

1) Feasibility and eventual construction and operation of an electronic current source of high stability and reproducibility.

2) Parallel operation of the electrical source and comparison of performance with the 226Ra sources.

3) In case of positive answer to point 1) gradual replacement and elimination of 226Ra sources used in the SIR.


PoW 2016-2019: Coordination activities

CIR-A1.1 Support to CCRI Provision of CCRI Executive Secretary, general support to CC and WGs plus

specifically support for: 1. Biennial CCRI and sections I, II and III meetings2. Regular meetings of 5 working groups3. Review of CC and RMO comparison reports before publication 4. Development of strategic plans 5. Publication of BIPM Monographies6. Review of CC and RMO comparison reports before publication7. Related liaisons with RMOs

CIR-A1.4Support to JCGM/WG1 - Regular meetings and Rapporteur

CIR-A1.5 International scientific collaboration - International Commission on Radiation Units (ICRU) (Commissioner and

sponsor of Report Committees),

- International Atomic Energy Agency (IAEA) (SSLD Scientific Committee),

- International Committee for Radionuclide Metrology (ICRM) (Scientific Committee and technical refereeing)

COORDINATION ACTIVITIES


PoW 2016-2019: ALTERNATIVE activities

Project Name Deliverables

IR-A1.3.1(alternative item)

High-energy electron dosimetry (accelerator dosimetry)See IR-A1.3 in prioritised projects for details

1) Development of a calorimeter standard for high-energy electrons, with the aim of providing equivalence and traceability for absorbed dose in electron beams through comparisons and characterizations of national standards. Requires 1 additional staff and frequent accessibility to an accelerator.

IR-A1.4.1(alternative item)

BrachytherapySee IR-A1.4 in prioritised projects for details

1) Extension to LDR 125I sources, to be decided by the CCRI(I) in 2015: 4 comparisons.

Alternative (Not-funded) activities

IR-A2.8(alternative project)

Development of the Becquerel ionization chamberTarget: prevention of eventual future obsolescence (long-term) of the SIR ionization chambers (IR-A2.1), by using an optimized backup chamber.Scope: enhanced robustness of SIR in the long-term, as additional safeguard to the current equivalence of more than 60 emitters used in nuclear medicine or appearing in the nuclear cycle and environmental monitoring.Participant (related) NMIs: 25

1) Analysis of conclusions of the BqWG(II) “Realization of the Becquerel” project (design robust, highly stable and reproducible chamber), and decision making about its suitability for the BIPM SIR. 2) If relevant to the BIPM, construction of the first BIPM prototype, operation in parallel to the conventional SIR chambers and comparison of performance. 3) If not relevant, prevision of backup of the existing chambers using commercial equipment.


PoW 2016-2019: ALTERNATIVE activities


BIPM internal service of thermometry calibrations - Internal calibration service of SPRTs and laboratory thermometers.



Development of a sandwich-type coincidence counter for - emitters

Target: new reference instrument to complete the primary measurement methods (IR-A2.5) available at the BIPM and the technical skills of staff for provision of new SIR entries and efficient comparisons coordination.Scope: comparisons of radionuclides used in nuclear medicine or appearing in the nuclear cycle and environmental monitoring.

Participant (related) NMIs: 25

1) Design, construction and experimental setup.

2) Operational tests with - emitters.

3) Support to CCRI (109Cd) and BIPM comparisons.

metrology and accelerator applications graeme taylor neutron metrology group national physical...

Documents

neutron reference fields3

fred metrology

fluence rates

rate of thermal field

graaff accelerator

fastthermal fluence

ion beam dosimetry

thermal pile8van