Activities and neutron facilities at the Laboratory for Neutron

Dosimetry and Metrology of IRSN

International Workshop on Fast Neutron TherapyEssen 14-16 September 2006

C MONNIN PARIETTI

Outline

Who are we?Neutron facilitiesMeasuring instrumentEvolution and progress

Who are we?Who are we?

Institute for Radiological protection and Nuclear SafetyCreated in 2002 : IPSN + OPRI (Inst. for Nucl. Protection and Safety and

Office for Protection against Ionizing Rays) : a public establishment of an industrial and commercial nature (EPIC).

IRSN is placed under joint authority of the ministries of Ecology, Health, Research, Industry and Defence.

1500 experts and researchers in nuclear safety and radiation protection as well as in the field of the control of nuclear and sensitive materials.

Contact http\\:www.irsn.orgHead of Laboratory : Carole MONNIN PARIETTI IRSN/ DRPH/ SDE/ LMDN – CadaracheBP3 – 13115 St PAUL LEZ DURANCE

- France-

Our missions Our missions

Experimental research and studiesmeasurement and assessment of dosesbiological and medical effects from irradiation and contaminationhealth effects of ionizing radiation

Assistance to the medical and public health management of accidents

Expertise in radiation protection for competent authorities

Legal surveillance of exposed workers

In charge of the national inventory of radioactive sources

Radiological Protection and Human Health Division Radiological Protection and Human Health Division

Structure and contacts

Structure and contacts

External Dosimetry Department(J.F Bottollier-Depois)

Radiological Protection and Human Health Division (DRPH - P. Gourmelon)

Neutrons Metrology and Dosimetry(LMDN – Cadarache,

C. Monnin-Parietti)

Ionising Radiation Dosimetry(LDRI – Fontenay-aux-Roses,

I. Clairand)

Dosimetry Monitoring(LSDOS – Vésinet,

F. Leblanc)

Radiation Protection Expertise Department (A. Rannou)

Internal Dosimetry Department (J.R Jourdain)

Radiobiology and Epidemiology Department (P. Voisin)

External Dosimetry Department External Dosimetry Department

Neutrons Metrology and Dosimetry(LMDN – Cadarache,

C. Monnin-Parietti)

Ionising Radiation Dosimetry(LDRI – Fontenay-aux-Roses,

I. Clairand)

Development and operation of reference radiation installationsfor ionising radiations metrology (own needs,

external customer, LNE/COFRAC activities

etc.).

Provision of service and expertise for the

qualification of radiation protection instruments

and for workplace characterisation.

Participation to national or international

authorities or working groups (CIPR, ISO, ICRU, CEI, EURADOS…), and to

the teaching.

Our missions

The laboratory located in Cadarache is responsible for

metrology – the science of measurement – and dosimetryof neutron radiation, with topics in radiation protection.

Laboratory for Neutron Dosimetry and Metrology Laboratory for Neutron

Dosimetry and Metrology

Our tasks may be divided into 4 mains fields :

Facilities producingreference neutron fields

MEASUREMENT

National standard (LNE) for Φ and HIRSN facilities are recognizedas reference neutron sources for the fluence and energydistribution

Expertise

Improvement in the

characterization of ourradiation fields

measurement methods

calculation

METROLOGY

Neutron dosimetrycalibration of measuringinstruments for neutron radiation

NEUTRON SPECTROMETRY

Investigations into neutron spectrometry workplaces, mixed fields (n,g).

COLLABORATIONS

Worldwide convergence of technicalpractices : developing multilateral or bilateral research (PTB, NPL, UAB…)Elaboration of technical recommendations(ISO, EUROMET, CCRI, EURADOS and others LNE, COFRAC…)

6 Physicists and Engineers

B. Asselineau, V. Gressier, J-F Guerre-Chaley, V. Lacoste,

L. Lebreton, L. Van Ryckeghem

2 techniciansG. Pelcot, A. Martin,

6 Physicists and Engineers

B. Asselineau, V. Gressier, J-F Guerre-Chaley, V. Lacoste,

L. Lebreton, L. Van Ryckeghem

2 techniciansG. Pelcot, A. Martin,

1 post-doc

K. Amgarou

2 PhD’s

A Alloua, S Serre

Students

1 post-doc

K. Amgarou

2 PhD’s

A Alloua, S Serre

Students

Head of laboratory: Mme C. Monnin-PariettiSecretary: Mme S. Nicolas

Structure and contacts

Structure and contacts

Neutron Facilities

dedicated to metrology and

neutron dosimetry

Neutron Facilities

dedicated to metrology and

neutron dosimetry

Van Gogh irradiator

Broad neutron fields

RADIONUCLIDE SOURCES« Van Gogh Irradiator »

10-6 10-5 10-4 10-3 10-2 10-1 100 1010,0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

E x ΔΦ

(E)/Δ

E (A

.U.)

Neutron Energy (MeV)

241Am -Be 252Cf (252Cf+D 2O)/Cd

<En> = 0.55 MeV

<En> = 2.1 MeV

<En> = 4.16 MeV

241AmBe et 252Cf (+D2O)

241Am-Be 252Cf (252Cf+D2O)/Cd252Cf+D2O

Emission (s-1) 4×107 3×108 3×108 3×108 •

Φ n (cm-2.s-1) 505 ± 8 4300 3700 3900

*•

H (10) (µSv.h-1) 711 ± 31 5900 1400 1400

•

pH (10,0°) (µSv.h-1) 747 ± 32 6100 1500 1500

RADIONUCLIDE SOURCES« Van Gogh Irradiator »

Neutron fluence and dose equivalent rates at the position wherecalibration are usually performed (75 cm) (date of 1st May 2005 for 252Cf)

Neutron Fluence rate

Individual Dose Equivalent rate

Ambiant Dose Equivalent rate

Van Gogh irradiator

Monoenergetic neutrons from 2 keV up to 20 MeV

SAMES Accelerator 400 kV “T400”d(D,n) reaction, Ed = 350 keV, En ~ 3.3 MeVMax Neutron fluence rate = 3 × 104 n.cm-2.s-1 (at 1 meter from the TiD, 0o)

SAMES Accelerator 120 kV “J25”d(T,n) reaction Ed = 120 keV, En ~ 14.8 MeVMax Neutron fluence rate = 5 × 105 n.cm-2.s-1 (at 1 meter from the TiT, 0o)

AMANDE: 2 MV Tandetron (Cockroft-Walton) (2005)Ed, Ep from 100 keV to 4 MeV, En from 2 keV to 20 MeVMax Neutron fluence rate = 9 × 103 n.cm-2.s-1 (at 1 m from the target, 0o)

Broad neutron fields

MONO-ENERGETIC NEUTRON FIELDS« T400 and J25 » neutron generators

J25 T400

SAMES Accelerator 400 kV “T400”D(d,n) reaction, Ed = 350 keV,En ~ 3.1 MeVEmission > 3×109 s-1 (4π)Φmax = 5×104 cm-2.s-1

(Neutron Fluence rate @ 1 m from the TiD, 0o)

SAMES Accelerator 150 kV “J25”

T(d,n) reaction Ed = 120 keV, En ~ 14.7 MeVEmission > 1.4×1010 s-1 (4π)Φmax = 5×105 cm-2.s-1

(Neutron Fluence rate @ 1 m from the TiT, 0o)

Van Gogh irradiatorMonoenergetic neutrons from 2 keV up to 20 MeVCanel Facility :

Broad neutron fields

REALISTIC NEUTRON FIELDS« CANEL »

end cap of the accelerator beam line and TiD or TiT target water lens or CH2

depleted Unat

iron

polyethylene

Produces realistic neutron spectra such as those encountered on workplaces, in order to calibrate dosimetric devices in similar distributions.

REALISTIC NEUTRON FIELDS: « CANEL »

Maximum neutron Fluence rate :

CANEL/T400, at 50 cm = 8. 10 3 n.cm-².s-1CANEL/J25 , at 30 cm = 8. 10 4 n.cm-².s-1

Maximum ambient dose equivalent rates:

CANEL/T400, at 50 cm = 1.3 mSv.h-1

CANEL/J25 , at 30 cm = 32 mSv.h-1

Neutron energy distribution :T400 J25

En ≤ 0.4 eV 56 % 54.7 %0.4 eV < En ≤ 10 keV 25 % 31 %10 keV < En ≤ 15 MeV 19 % 14.3 %

The CANEL assembly is designed to convert and moderate fast mono energetic neutrons produced by two accelerators

The canel energy distribution extends from thermal range up to few MeV, as it can beobserved in nuclear power plant (for example)

Van Gogh irradiatorMonoenergetic neutrons from 2 keV up to 20 MeVCanel Facility :

Thermal neutron field at Sigma facility

Broad neutron fields

Thermal neutron field« SIGMA »

The moderator block: • pure graphite • dimensions 1.5 × 1.5 × 1.5 m3

• 2 m above concrete floor

Radioactive sources:- 6 241Am-Be sources : 96 Ci- 1.9071×108 ± 2.2% s-1 (4π)

SIGMA SIGMA+

The moderator block: • pure graphite • dimensions 2.4 × 2.4 × 2.4 m3

• on concrete floor

Radioactive source:- 1 252Cf source : 268 mCi- 1.15×109 ± 0.6% s-1 (4π)

No more availa

ble, new th

ermal fa

cility under study

Facility upgrade

SIGMA SIGMA+

Total En < 0.5 eVΔΦ/Δt (cm-2.s-1) 1767 ± 55 88.4% ΔH*(10)/Δt (μSv.h-1) 144 ± 5 43.9%

Total En < 0.5 eV dΦ/dt (cm-2.s-1) 4140-1081 99.9% dH*(10)/dt (μSv.h-1) 168-44 99.0%

Pure thermic fieldHomogeneous on 30 cm (Φ et H)4 positions of calibration

Realistic field with thermal composant1 position of calibration

Thermal neutron field« SIGMA »

Van Gogh irradiatorMonoenergetic neutrons from 2 keV up to 20 MeVCanel Facility : Thermal neutron field at Sigma facility

Mono energetic neutron fields « AMANDE »It is complement existing facility of the Laboratory for study and research.

Broad neutron fields

« AMANDE » is intended to produce monoenergetic neutrons

2 MV Tandetron (Cockroft-Walton)

Amande is a « Tandetron »

● it can accelerate any type of charged particle.

● It provide beams with a lowdispersion

● Its 2MV high Voltage is set with a current rectification system.

● Amande has the capacity to provide proton and deuteron beams, with energies between 100 keV and 4 MeV, witch will be determindedwith a precision of less than 500 eV.

Ed, Ep from 100 keV to 4 MeV,

En from 2 keV to 20 MeV

Ion source (H- and D-)

Pulsing system (chopper / buncher)

Accelerator

Beamline

Target(neutron source)

Switching magnet(5 beamlines) Analysing magnets

Amande is used to study and characterise the behaviour of bothexisting measuring devices and those presently being developedfor radiological protection of workers expose to neutron radiation.

6 m

20 m

4.5 m

6 m

Metallic walls

Beam line

Metallic grid

8 m

20 m

Automated positioning system

Accelerator 1.2 m

6 m

20 cm concrete

40 cm concrete wall

The design of the building housing the accelerator. The very low proportion of concrete in the builkdingstructure will decrease significantly the « background » generated by neutrons scateered by the walls.

En from 2 keV to 20 MeV

In addition to its use for neutron studies, AMANDE will also be usedto produce high energy photon reference radiation.

Amande can deliver continuous or pulsed currents (the energy of the accelerated particles can easilychanged)

The charged particles beam maybe pulsed in order to perform time of flight measurements of the neutrons (purpose is measurementof neutron velocity and thereforetheir energy) performed by determining the time they take to cover a given distance.

Two running modes

- Continuous mode, Imax = 50 mA

- Pulsed mode for time-of-flight measurements2 ns pulse width62.5 kHz to 2 MHzImax = 8 mA (@ 2MHz)

Energy resolution of the charged particle incident beam

- DC mode, Precision less than 0.7 keV

- AC mode, Precision less than 4 keV

AMANDE NEUTRON FIELDSACCELERATOR PERFORMANCES

MONO-ENERGETIC NEUTRON FIELDS« AMANDE »

Reactions Neutron energies at 0o

45Sc(p, n)45Ti 5.6 keV to 52 keV

7Li(p,n)7Be 120 keV to 650 keV

T (p, n) 3He 288 keV to 3.2 MeV

D(d, n)3He 2.5 MeV to 7.3 MeV

T (d, n) 4He 14.6 MeV to 20.5 MeV

19F(p,αγ)16O γ: 6.13 + 6.92 + 7.12 MeV

Only some reactions are likely to deliver

monoenergetic neutrons.

Most are based upon the interaction between

protons, deuterons and nuclei of elemnts such as

copper, scandium, lithium, deuterium or tritium.

Champs de neutrons

“réalistes”

31Monoenergetic neutron fields

(0,025 eV to 20 MeV)

2Radioactives sources

(241Am-Be, 252Cf, (252Cf+D2O)/Cd)

Van Gogh CANEL SIGMASIGMA AMANDE J25+T400

ISO 8529 & ISO 12789. Reference Neutron Radiations (2001).

• Elaborate technical recommendations• Harmonization of the protocol at

an international level

Reference neutron radiation

MeasuringinstrumentMeasuringinstrument

Detectors for spectrometry using deconvolution procedures

Bonner sphere spectrometer

(active BSS (NH3/SP9) & passive BSS (Au Foils))

ROSPEC spectrometer

BC501A/NE213 Liquid scintillator

Proton recoil detectors as neutron secondary reference

Spherical Proportional counters (H2, CH4).Liquid scintillator BC 501 A

Photon spectrometers for measurement in mixed neutron/photon radiation fields

Liquid scintillator BC501A/NE213 1.5 MeV <En< keV to 10 MeV100 keV <Eγ< 10 MeV

BGO 300 keV <Eγ< 10 MeV

BSS system serves as a reference system for the spectrometry and dosimetryof unknown neutron fields in the wide energy range of thermal neutrons up to about 20 Mev at the present

Our spectrometer consists of a set of 12 Bonner spheres of polyethylene 2.5”to 12” in diameter. In its centre there are spherical proportional counters which are filled with 3He gas and thus are very sensitive to thermalized neutrons.

Bonner Spheres SystemThermal – 20 MeV (and more …)

The Bonner Sphere Spectrometer serves to determinethe neutron fluence as well as the energy distribution of neutrons.

� A PhD study consists of the improvement of suchspectrometer AT HIGH NEUTRON ENERGIES (> 20 MeV)

� A Post doctoral research deals with a set up passive spectrometer dedicated to MIXED FIELD WITH A VERY INTENSE AND HIGH ENERGETIC PHOTON COMPONENT. (Au foils)

K Amgarou talk

Bonner Spheres SystemThermal – 20 MeV (and more …)

Bonner Spheres System

The total neutron fluence can be determined by suitabledeconvolution methods with incertainties of 5%. We the aid of recommended conversion coefficients, dose equivalent quantities (ambient dose equivalent ) can bedetermined from the neutron spectrum.

The spectrometer is used, amoung others instruments, for measurement at workplaces in nuclear industry as well as, in the future, for the investigation of the neutron component of medical facilities.

Proton recoil proportional counters

Sphere

Polar Tube

Wire Holder

Anodic Wire Axis

np

e-

Gaz : H2, CH4, …

Avalanche

4 cm

Sphere

Polar Tube

Wire Holder

Anodic Wire Axis

np

e-

Gaz : H2, CH4, …

Avalanche

4 cm

BC501A liquid scintillator

SP2 proton recoil proportional counters

ROSPEC

CelluleBC501A

Guide delumière

Photomultiplicateur

Pré-amplificateur

BC501Acell

Lightguide

Photomultiplier

Pre-amplifier

Proton recoil proportional counters

SP2(H2) + SP2 (CH4)

Fine referencespectrometry

Neutron energy range : ~ keV – 5 MeV

Low efficiency : e ~ 1%

Good energy resolution : DEn/En ~ 5 à 15 %

Neutron fluence accuracy: ~ 3 à 5 %

Sphere

Polar Tube

Wire Holder

Anodic Wire Axis

np

e-

Gaz : H2, CH4, …

Avalanche

4 cm

Sphere

Polar Tube

Wire Holder

Anodic Wire Axis

np

e-

Gaz : H2, CH4, …

Avalanche

4 cm

BC501A proton recoil liquid scintillator

CelluleBC501A

Guide delumière

Photomultiplicateur

Pré-amplificateur

BC501Acell

Lightguide

Photomultiplier

Pre-amplifier

Fine reference spectrometry

Neutron energy range : 1 MeV – 30 MeV (2”x2”)

High efficiency : e > 10 %

Good energy resolution : ΔEn/En ~ 1 à 3 %

Neutron fluence accuracy: ~ 3 à 5 %

For simultaneous spectrometry of neutrons and photons in mixed fields, a spectrometer with the liquidscintillator BC501 A is used.

The separation of the events induced by photons and neutrons is carried out by fastanalog pulse shape analysis of the measurementsignals which are detected using a multiparameterdata acquisition system.

BC501A proton recoil liquid scintillator

The scintillation spectrometer is employed, among other things, to characterize the mixed radiation fields.

The measured fluences and the energy-dependent fluence – to-dose conversion coefficients yield the dose fractions for the neutrons and photons of these radiation fileds which are used for the calibration of neutron area dosemeters and for irradiations of neutron personal dosemeters.

The further analysis takes place separately for photon and neutron events in the energy ranges 0.1 MeV to 10 MeV for photons and 1 MeV to 30 MeV for neutrons.

Neutron fluence as well as energy distribution of neutrons

HarwellStudwick

Neutron fluence and dose equivalent rate on IRSN neutron sources AmBe, Cf, Cf+D20

Liquid scintillatorBC501A

Bonner spherespectrometer

Spherical Proportional counters(H2, CH4)

Reference system

100 keV to 2.5 MeV

Thermal to 20 MeV2 Mev to 20 MeV

Thermal 50 keV 1 MeV 5 MeV 20 MeV

SP2Proton recoil

4 cm4 cm4 cm4 cm

Bonner sphere spectrometer

BC501AProton recul

Measuring instrument for Workplaces investigations

BC501A/NE213Proton recul

ROSPECProton recul + 3He

Multi-sphère3He

Thermal - 4.5 MeV

Thermal – 20.0 MeV

1.5 MeV - 20 MeV

100 keV – 2.5 MeV

Development of instruments

Recoil proton telescopes (as neutron primary standard instrument)

Passive Bonner spheres systems (Au fiols) (medical application)

Study and design of a spectrometer for high energy neutrons

Design of reference neutron monitors (long counters) for AMANDE facilities.

Conclusions and Perspectives

Conclusions and Perspectives• Availability of all neutron facilities for external users

• Characterization of the AMANDE neutron fieldsopen for external users

• Design of a new facility for a pure thermal field production

• Other configurations of the CANEL assembly (simulated workplace fields)

• Spectrometry at workplaces(nuclear industries, medical, et

• Characterization of a passive Bonner spheres system (Au foils)

• Study and design of a spectrometer for high energy neutrons

The IRSN neutron facilities allow measurements over a wide energy range from thermal to 20 MeVvarious neutron energy distributions

IRSN facilities are being recognized as reference neutron sources

Reference values for the fluence and energy distributionReference energies by t.o.f measurements (En > 10 keV)Reference instruments (proton recoil detectors, long counters, …)

Reference facilities for photons – AMANDE, – Cs irradiator, – X-rays generators

Conclusions and Perspectives

02-IRSN/47/GG

Workplaces Measurements

Dampierre en BurlyEssen (Allemagne)

la Centrale Nucléaire Vandellós II

CANEL

IRRADIATION FACILITIES

MEASUREMENT

Participation to national or international authorities or working groups (CIPR, ISO, ICRU, CEI, EURADOS…), and to the teaching.

Laboratory for neutron Dosimetry and Metrology Laboratory for neutron Dosimetry and Metrology

RESEARCH

We do research to improve measuring techniques and calculation for Neutron Radiation in order to improve more and more our methods and precision.

We render services and expertise for the qualification of radiation protection instruments (calibration of measuring instruments for neutron radiation) and for workplace characterisation (by investigation of their characteristics).

Characterize our radiation fields.

Development of our reference radiation facilities for neutron radiations metrology (own needs, external customer, LNE/COFRAC activities etc.), for specific investigations (biological effect of neutrons, protons and alpha particles)

COLLABORATIONS

FacilitiesFacilities DetectorsDetectors

Workplaces measurementsWorkplaces measurements

Références

ISO – BNM - COFRACISO – BNM - COFRAC

InformaticSecurityQuality

Scientific coord. V. Gressier L. Lebreton

Scientific coord. : V. Lacoste

Scientific coord. : V. Gressier

Facilities coord : JF. Guerre-Chaley

Scientific coord. : L. Van Ryckeghem

Modelisation (facilities, detectors, etc.)Modelisation (facilities, detectors, etc.)

Scientific coord. : V. Lacoste

Laboratory for Neutrons Dosimetry and Metrology (LMDN)