Activities and neutron facilities at the Laboratory for Neutron Dosimetry and Metrology of IRSN

Transcription

1 Activities and neutron facilities at the Laboratory for Neutron Dosimetry and Metrology of IRSN International Workshop on Fast Neutron Therapy Essen September 2006 C MONNIN PARIETTI

2 Outline Who are we? Neutron facilities Measuring instrument Evolution and progress

3 Who are we? Who are we?

4 Institute for Radiological protection and Nuclear Safety Created 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 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\\: Head of Laboratory : Carole MONNIN PARIETTI IRSN/ DRPH/ SDE/ LMDN Cadarache BP St PAUL LEZ DURANCE -France-

5 Our missions Our missions

6 Radiological Protection and Human Health Division Radiological Protection and Human Health Division Experimental research and studies measurement and assessment of doses biological and medical effects from irradiation and contamination health 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

7 Structure and contacts

8 Radiological Protection and Human Health Division (DRPH - P. Gourmelon) Radiation Protection Expertise Department (A. Rannou) Internal Dosimetry Department (J.R Jourdain) Radiobiology and Epidemiology Department (P. Voisin) External Dosimetry Department (J.F Bottollier-Depois) Neutrons Metrology and Dosimetry (LMDN Cadarache, C. Monnin-Parietti) Dosimetry Monitoring (LSDOS Vésinet, F. Leblanc) Ionising Radiation Dosimetry (LDRI Fontenay-aux-Roses, I. Clairand)

9 External Dosimetry Department External Dosimetry Department Neutrons Metrology and Dosimetry (LMDN Cadarache, C. Monnin-Parietti) Ionising Radiation Dosimetry (LDRI Fontenay-aux-Roses, I. Clairand) Our missions Development and operation of reference radiation installations for 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.

10 Laboratory for Neutron Dosimetry and Metrology The laboratory located in Cadarache is responsible for metrology the science of measurement and dosimetry of neutron radiation, with topics in radiation protection. Our tasks may be divided into 4 mains fields :

11 Facilities producing reference neutron fields METROLOGY Expertise MEASUREMENT National standard (LNE) for Φ and H IRSN facilities are recognized as reference neutron sources for the fluence and energy distribution Improvement in the characterization of our radiation fields measurement methods Neutron dosimetry calibration of measuring instruments for neutron radiation COLLABORATIONS calculation Worldwide convergence of technical practices : developing multilateral or bilateral research (PTB, NPL, UAB ) Elaboration of technical recommendations (ISO, EUROMET, CCRI, EURADOS and others LNE, COFRAC ) NEUTRON SPECTROMETRY Investigations into neutron spectrometry workplaces, mixed fields (n,g).

12 Structure and contacts Head of laboratory: Secretary: 6 Physicists and Engineers B. B. Asselineau, V. V. Gressier, J-F Guerre-Chaley, V. V. Lacoste, L. L. Lebreton, L. L. Van Ryckeghem 2 technicians G. G. Pelcot, A. A. Martin, Mme C. Monnin-Parietti Mme S. Nicolas 1 post-doc K. K. Amgarou 2 PhD s A Alloua, S Serre Students

13 Neutron Facilities dedicated to metrology and neutron dosimetry

14 Broad neutron fields Van Gogh irradiator

15 RADIONUCLIDE SOURCES «Van Gogh Irradiator» 241 AmBe et 252 Cf (+D 2 O) E x ΔΦ(E)/ΔE (A.U.) 0,8 0,7 0,6 0,5 0,4 0,3 241 Am-Be 252 Cf ( 252 Cf+D 2 O)/Cd <En> = 4.16 MeV <En> = 2.1 MeV 0,2 <En> = 0.55 MeV 0,1 0, Neutron Energy (MeV)

16 RADIONUCLIDE SOURCES «Van Gogh Irradiator» Neutron fluence and dose equivalent rates at the position where calibration are usually performed (75 cm) (date of 1 st May 2005 for 252 Cf) 241 Am-Be 252 Cf ( 252 Cf+D 2 O) /Cd 252 Cf+D 2 O Emission (s -1 ) Φ n (cm -2.s -1 ) H *(10) (µsv.h -1 ) H (10,0 ) (µsv.h -1 ) p 505 ± ± ± Neutron Fluence rate Individual Dose Equivalent rate Ambiant Dose Equivalent rate

17 Broad neutron fields 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 MeV Max Neutron fluence rate = 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 MeV Max Neutron fluence rate = 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 MeV Max Neutron fluence rate = n.cm-2.s-1 (at 1 m from the target, 0o)

18 MONO-ENERGETIC NEUTRON FIELDS «T400 and J25» neutron generators J25 T400 SAMES Accelerator 400 kv T400 D(d,n) reaction, E d = 350 kev, E n ~ 3.1 MeV Emission > s -1 (4π) Φ max = cm -2.s -1 (Neutron Fluence 1 m from the TiD, 0 o ) SAMES Accelerator 150 kv J25 T(d,n) reaction E d = 120 kev, E n ~ 14.7 MeV Emission > s -1 (4π) Φ max = cm -2.s -1 (Neutron Fluence 1 m from the TiT, 0o)

19 Broad neutron fields Van Gogh irradiator Monoenergetic neutrons from 2 kev up to 20 MeV Canel Facility :

20 REALISTIC NEUTRON FIELDS «CANEL» Produces realistic neutron spectra such as those encountered on workplaces, in order to calibrate dosimetric devices in similar distributions. end cap of the accelerator beam line and TiD or TiT target water lens or CH 2 depleted U nat iron polyethylene

21 Maximum neutron Fluence rate : REALISTIC NEUTRON FIELDS: «CANEL» The CANEL assembly is designed to convert and moderate fast mono energetic neutrons produced by two accelerators CANEL/T400, at 50 cm = n.cm - ².s - 1 CANEL/J25, at 30 cm = 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 energy distribution extends from thermal range up to few MeV, as it can be observed in nuclear power plant (for example)

22 Broad neutron fields Van Gogh irradiator Monoenergetic neutrons from 2 kev up to 20 MeV Canel Facility : Thermal neutron field at Sigma facility

23 SIGMA Thermal neutron field «SIGMA» SIGMA+ The moderator block: pure graphite dimensions m 3 2 m above concrete floor Radioactive sources: Am-Be sources : 96 Ci ± 2.2% s -1 (4π) Facility upgrade No more available, new thermal facility under study The moderator block: pure graphite dimensions m 3 on concrete floor Radioactive source: Cf source : 268 mci ± 0.6% s -1 (4π)

24 SIGMA Thermal neutron field «SIGMA» SIGMA+ Total E n < 0.5 ev ΔΦ/Δt (cm -2.s -1 ) 1767 ± % ΔH*(10)/Δt (μsv.h -1 ) 144 ± % Realistic field with thermal composant 1 position of calibration Total En < 0.5 ev dφ/dt (cm -2.s -1 ) % dh*(10)/dt (μsv.h -1 ) % Pure thermic field Homogeneous on 30 cm (Φ et H) 4 positions of calibration

25 Broad neutron fields Van Gogh irradiator Monoenergetic neutrons from 2 kev up to 20 MeV Canel Facility : Thermal neutron field at Sigma facility Mono energetic neutron fields «AMANDE» It is complement existing facility of the Laboratory for study and research.

26 «AMANDE» is intended to produce monoenergetic neutrons 2 MV Tandetron (Cockroft-Walton) E n from 2 kev to 20 MeV Amande is a «Tandetron» it can accelerate any type of charged particle. It provide beams with a low dispersion 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 determinded with a precision of less than 500 ev. E d, E p from 100 kev to 4 MeV,

27 Amande is used to study and characterise the behaviour of both existing measuring devices and those presently being developed for radiological protection of workers expose to neutron radiation. Switching magnet (5 beamlines) Analysing magnets Beamline Target (neutron source) Accelerator Pulsing system (chopper / buncher) Ion source (H - and D - )

28 The design of the building housing the accelerator. The very low proportion of concrete in the builkding structure will decrease significantly the «background» generated by neutrons scateered by the walls. 40 cm concrete wall Metallic walls 6 m Accelerator Beam line Automated positioning system 8 m 1.2 m 6 m Metallic grid 6 m 4.5 m 20 cm concrete 20 m 20 m

29 In addition to its use for neutron studies, AMANDE will also be used to produce high energy photon reference radiation. Amande can deliver continuous or pulsed currents (the energy of the accelerated particles can easily changed) E n from 2 kev to 20 MeV The charged particles beam may be pulsed in order to perform time of flight measurements of the neutrons (purpose is measurement of neutron velocity and therefore their energy) performed by determining the time they take to cover a given distance.

30 Two running modes AMANDE NEUTRON FIELDS ACCELERATOR PERFORMANCES - Continuous mode, Imax = 50 ma - Pulsed mode for time-of-flight measurements 2 ns pulse width 62.5 khz to 2 MHz Imax = 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

31 MONO-ENERGETIC NEUTRON FIELDS «AMANDE» Reactions Neutron energies at o 0 45 Sc(p, n) 45 Ti 5.6 kev to 52 kev 7 Li(p,n) 7 Be 120 kev to 650 kev T (p, n) 3 He D (d, n) 3 He T (d, n) 4 He 288 kev to 3.2 MeV 2.5 MeV to 7.3 MeV 14.6 MeV to 20.5 MeV 19 F(p,αγ) 16 O γ: 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.

32 Reference neutron radiation Elaborate technical recommendations Harmonization of the protocol at an international level ISO 8529 & ISO Reference Neutron Radiations (2001). 1 Monoenergetic neutron fields (0,025 ev to 20 MeV) 2 Radioactives sources ( 241 Am-Be, 252 Cf, ( 252 Cf+D 2 O) /Cd ) 3 Champs de neutrons réalistes SIGMA AMANDE J25+T400 Van Gogh CANEL SIGMA

33 Measuring instrument

34 Detectors for spectrometry using deconvolution procedures Bonner sphere spectrometer ROSPEC spectrometer (active BSS (NH3/SP9) & passive BSS (Au Foils)) 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/NE MeV <En< kev to 10 MeV 100 kev <Eγ< 10 MeV BGO 300 kev <Eγ< 10 MeV

35 Bonner Spheres System Thermal 20 MeV (and more ) BSS system serves as a reference system for the spectrometry and dosimetry of 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 3 He gas and thus are very sensitive to thermalized neutrons.

36 Bonner Spheres System Thermal 20 MeV (and more ) The Bonner Sphere Spectrometer serves to determine the neutron fluence as well as the energy distribution of neutrons. A PhD study consists of the improvement of such spectrometer 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

37 Bonner Spheres System 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. The total neutron fluence can be determined by suitable deconvolution methods with incertainties of 5%. We the aid of recommended conversion coefficients, dose equivalent quantities (ambient dose equivalent ) can be determined from the neutron spectrum.

38 Proton recoil proportional counters Photomultiplicateur Photomultiplier BC501A liquid scintillator Pré-amplificateur Pre-amplifier Guide Light de lumière guide Cellule BC501A BC501A cell SP2 proton recoil proportional counters 4 cm ROSPEC Gaz : H 2,CH 4, p e - Sphere n Polar Tube Wire Holder Anodic Wire Axis Avalanche

39 Proton recoil proportional counters SP2(H 2 ) + SP2 (CH 4 ) 4 cm Fine reference spectrometry Gaz : H 2,CH 4, Neutron energy range : ~ kev 5 MeV p e - Sphere n Polar Tube Wire Holder Anodic Wire Axis Low efficiency : e ~ 1% Good energy resolution : DE n /E n ~ 5 à 15 % Avalanche Neutron fluence accuracy: ~ 3 à 5 %

40 BC501A proton recoil liquid scintillator Pré-amplificateur Pre-amplifier Photomultiplicateur Photomultiplier Guide Light de lumière guide Cellule BC501A BC501A cell For simultaneous spectrometry of neutrons and photons in mixed fields, a spectrometer with the liquid scintillator BC501 A is used. Fine reference spectrometry Neutron energy range : 1 MeV 30 MeV (2 x2 ) High efficiency : e > 10 % Good energy resolution : ΔE n /E n ~ 1 à 3 % Neutron fluence accuracy: ~ 3 à 5 % The separation of the events induced by photons and neutrons is carried out by fast analog pulse shape analysis of the measurement signals which are detected using a multiparameter data acquisition system.

41 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 todose 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.

42 Reference system Neutron fluence as well as energy distribution of neutrons 2 Mev to 20 MeV Bonner sphere spectrometer Thermal to 20 MeV 100 kev to 2.5 MeV Liquid scintillator BC501A Spherical Proportional counters (H2, CH4) Neutron fluence and dose equivalent rate on IRSN neutron sources AmBe, Cf, Cf+D 2 0 Studwick Harwell

43 Measuring instrument for Workplaces investigations Multi-sphère 3 He Bonner sphere spectrometer Thermal 20.0 MeV Thermal MeV 100 kev 2.5 MeV ROSPEC Proton recul + 3 He 4 cm SP2 Proton recoil 1.5 MeV - 20 MeV BC501A BC501A/NE213 Proton recul Proton recul Thermal 50 kev 1 MeV 5 MeV 20 MeV

44 Conclusions and Perspectives 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.

45 Conclusions and Perspectives Availability of all neutron facilities for external users Characterization of the AMANDE neutron fields open 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

46 Conclusions and Perspectives The IRSN neutron facilities allow measurements over a wide energy range from thermal to 20 MeV various neutron energy distributions IRSN facilities are being recognized as reference neutron sources Reference values for the fluence and energy distribution Reference energies by t.o.f measurements (E n > 10 kev) Reference instruments (proton recoil detectors, long counters, ) Reference facilities for photons AMANDE, Cs irradiator, X-rays generators

47 02-IRSN/47/GG CANEL Essen (Allemagne) Dampierre en Burly Workplaces Measurements la Centrale Nucléaire Vandellós II

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

49 Laboratory for Neutrons Dosimetry and Metrology (LMDN) Facilities Detectors Facilities coord : JF. Guerre-Chaley Références Scientific coord. : V. Gressier Scientific coord. V. Gressier L. Lebreton ISO BNM - COFRAC ISO BNM - COFRAC Scientific coord. : L. Van Ryckeghem Modelisation (facilities, detectors, etc.) Modelisation (facilities, detectors, etc.) Scientific coord. : V. Lacoste Workplaces measurements Workplaces measurements Scientific coord. : V. Lacoste Quality Security Informatic