Physics and Commissioning of PARIS

Transcription

1 Physics and Commissioning of PARIS Story began in 2006 with request of a next-generation high-energy γ-rays calorimeter Sum up from «Physics & Theory» Working Group ( ) - study of the physics proposed at the collaboration - potential links / complementarity between different topics - feasibility of related experiments Protocol and commissioning of PROVA/PARIS cluster(s) at IPNO - calibration and characterization of response function = f (E γ ) - performance: efficiency ε, resolution, linearity, n-γ dicrimination Recent new topic for fundamental and applied issues in fission - ERINDA collaboration for experiment in interesting environment

2 Task of the Physics & Theory WG Basis : - Heavy-ion fusion reactions (evaporation evaporation/fission) - High-energy photons (~ 4-40MeV) 40MeV) - Low-energy (discrete discrete) γ-rays (E sum γ and M γ ) Additionnal : Measurement of coincident particles, heavy-ions,... Physics & Theory WG: Collect the various proposals and requests Relevance of - and bridges between - different topics Report on to the collaboration Study the experimental feasibility «Advertize» the PARIS project

3 PARIS Physics Cases (1) 1. Giant Dipole Resonance = f (T,L) and shape transitions Hot GDR studies in hot neutron-rich rich nuclei (D. Chakrabarty, M. Kmiecik) Evolution of E GDR and Γ GDR with T and L along (N,Z) chains e.g Sn(~5-6AMeV)+ 12 C Ba* Isospin mixing (M. Kicinska-Habior Habior) Hindrance of E1 emission in T=0 nuclei e.g. 44 Ti(~3-5AMeV)+ 24 Mg 68 Se* Shape phase diagram of hot nuclei (A. Maj,, I. Mazumdar) (Non)-collective nature of rotation / Criticity of shape phase transition e.g Xe(~4AMeV)+ 48 Ti Os* Jacobi and Poincaré shape transitions (A. ( Maj,, J. Dudek, P. Bednarczyk) Angular momentum-driven shape transition e.g. 94 Kr(~9AMeV)+ 24 Mg 120 Cd*

4 2. Reaction mechanism PARIS Physics Cases (2) Radiative capture (D. Jenkins, S. Courtin) GDR on highly-deformed states: a doorway to nuclear molecules? e.g. 12 C(~1-2AMeV)+ 12 C 24 Mg* Fusion and (quasi-)fission dynamics, reacion time scales and nuclear viscosity (Ch. Schmitt, O. Dorvaux) Track the dynamical shape evolution via GDR clock with T (E sum γ ) or L (M γ ) e.g. 16 O(~5-10AMeV)+ 197 Au 213 Fr* Demise of collectivity and onset of multifragmentation (J.-P. Wieleczko) Establishment of collective phenomena disturbed by local correlations No time to equilibrate prior break-up Concept of mean-field meaningless e.g. 64 Ni(~7-12AMeV)+ 68 Zn 132 Ce*

5 PARIS Physics Cases (3) 3. Shell structure (with various approaches) Multiple (normal) Coulex (P. Napiorkowski, A. Maj,, F. Azaiez) Electromagnetic properties of SD bands e.g. 40 Ca(~4AMeV)+ 208 Pb 40 Ca* Shell structure with intermediate-energy energy spectroscopy (Zs Zs. Dombradi) Evolution of nuclear structure and magicity away from stability e.g. rad Ne- rad Ar(~50-500AMeV) fragmentation And others... Structure of (unknown) neutron-rich nuclei produced at 0 in S3 (I. Stefan, F. Azaiez, B.Fornal) Relativistic Coulex (P. Bednarczyk) Astrophysics (S. Harissopulos) NB: medium-energy energy γ-rays [1-6]MeV, M γ < 3, but tiny σ: efficiency is crucial..and what would be your great idea? It is never too late!

6 Physics and Commissioning of PARIS Story began in 2006 with request of a next-generation high-energy γ-rays calorimeter Sum up from «Physics & Theory» Working Group ( ) - study of the physics proposed at the collaboration - potential links / complementarity between different topics - feasibility of related experiments Protocol and commissioning of PROVA/PARIS cluster(s) at IPNO - calibration and characterization of response function = f (E γ ) - performance: efficiency ε, resolution, linearity, n-γ dicrimination Recent new topic for fundamental and applied issues in fission - ERINDA collaboration for experiment in interesting environment

7 Motivation for the testing protocol Photon energy range of PARIS: [~ 0 40] MeV! Interaction of γ-rays in matter is strongly E γ dependent (photoelectric effect, Compton scattering and annihilation have very different deposit patterns in the detector) Diffusion of high-energy γ-rays in several cells Non-linearities in the electronics Extrapolation from low to high energies hazardeous and inaccurate Characterization mandatory for many mono-energetic γ-rays scanning an as wide as possible range Accurate response function = f (E γ ) : critical input for accurate reconstruction of the incident photon by software

8 Strategy for the testing protocol Radioactive sources : 22 Na, 60 Co, 133 Ba, 137 Cs, 152 Eu, 241 Am- 9 Be, 238 Pu- 13 C,... provide regularly-spaced γ-ray lines up to E γ = 6.13MeV Nuclear reactions are necessary for populating states which decay by higher-energy energy γ-rays Proposal for protocol and related issues, including: Collection of reactions useful for PARIS, 19 F(p,αγ) 16 O, 27 Al(p,γ) 28 Si, 23 Na(p,γ) 24 Mg, 7 Li(p,γ) 8 Be, 11 B(p,γ) 12 C, 12 C(p,p )γ, d( 11 B,n)γ,... Available relevant facilities, IPNO, ATOMKI, IFJ Krakow, TIFR-BARC, IUAC, Warsaw, GANIL, Rossendorf, HIγS documented in report on Outcome: IPN Orsay is the only place in Europe with a wide proton beam beam energy range and, importantly, the high-energy protons (E p >17MeV) leading to the emission of γ-rays with energies above E γ ~16MeV

9 The IPNO commissioning experiment

10 IPNO experiment: Systems and goals Determine the response function of the cluster over a wide energy range 1. Radioactive sources 2. Nuclear reactions Isotope E γ (kev) 207 Bi 570;1063; Cs Co 1173; Co 1771;2034; 2598;3253 Reaction E γ (kev) p(1.3mev)+ 23 Na 570;1063; 1770 p(1.35mev)+ 39 K 662 p(22mev)+ 12 C (3215;4439); 15100; Reaction p(7mev)+ nat B Population of states de-exciting exciting by photons up to E γ ~ 22MeV Coincident emission of neutrons Calibrated standard sources + «Point-Pair» Pair» method: ε up to high E γ Low M γ : wise approach for reconstruction software E γ (kev) d(3.1mev)+ nat B and neutrons d(3-10mev)+ 12 C (3215;4439) and neutrons Response function of phoswichs and cluster (cross talk study), linearity, efficiency, energy and time resolution, n-γ discrimination by T of

11 IPNO experiment: Set-up Beam related Maximum available intensity (20pnA) E p [1.3-22]MeV, E d [3-10]MeV Target area related Thickness: 6µg/cm 2 ( 12 C) to 1mg/cm 2 ( 11 B) Dedicated reaction chamber 13cm Electronics TNT2 (IPHC), BAFPRO Milano (cf. O.Dorvaux, F.Camera) Allocated beam time: 15 UT s Scheduled in April 2013 Detection PROVA 15cm 2 nd PARIS cluster and/or individual phoswichs 4 Ge detectors Single LaBr 3 (Ce) scintillators Scanning of all phoswichs with collimated source at IPHC for homogeneity issues Anyone willing to join is welcome

12 Physics and Commissioning of PARIS Story began in 2006 with missing a modern high-energy γ-rays / calorimeter detection Sum up from «Physics & Theory» Working Group ( ) - study of the physics proposed at the collaboration - potential links / complementarity between different topics - feasibility of related experiments Protocol and commissioning of PROVA/PARIS cluster(s) at IPNO - calibration and characterization of response function = f (E γ ) - performance: efficiency ε, resolution, linearity, n-γ dicrimination Recent new topic for fundamental and applied issues in fission - ERINDA collaboration for experiment in interesting environment

13 New physics case: Prompt fission γ ray mean energy and multiplicity from the reaction 238 U(n,f n,f) as a function of E n (1) A. Oberstedt et al. (Göteborg), J. Wilson et al. (Orsay) for ERINDA (European Research Infrastructures for Nuclear Data Applications) Two-fold motivation : 1. Applications: Control the heating in reactors - fission-fragment kinetic energy - 10% of heat from γ rays: 40% are prompt FF γ-rays safety of the core reactor - modern calculations are unaccurate need of data on spectral shape, E γ and M γ ON THE HIGH PRIORITY LIST of NEA/OECD n ~ 10-3 s n ~ s β β 235 U Stable Nucleus n ~ 10-3 s n ~ 10-9 s β β Stable Nucleus 2. Fundamental interest: LaBr3 offer a new opportunity (ε, E, t) - how is the angular momentum generated in fission - how are E* and L shared between the 2 FF s? - does sharing depend on the fission mode? - n/γ-ray emission competition

14 New physics case: Prompt fission γ ray mean energy and multiplicity from the reaction 238 U(n,f n,f) as a function of E n (2) Experimental approach: LICORNE (IRMM Belgium, IPNO) : intensely focused mono-energetic [0.5-4]MeV n source (10 7 n/s/sr) higher n intensity on target and lower n background H target 100nA 7 Li MeV γ γ n n n n Actinide sample 4 LaBr3 from IPNO 2 LaBr3 from IRMM... and possibly PARIS For ERINDA: PARIS efficiency is crucial for highest γ rays (above 10MeV) which are those which have the longest mean free path For PARIS: Prompt fission neutrons for studying n-γ discrimination Higher Mγ environment For both: fundamental aspets Scheduled in June 2013

15 Conclusion and Outlook Widespread panoply of exciting physics cases implying various conditions (E γ, M γ, environment) Challenge: cope with all requirements with a single detector... And still open to new exotic propositions! Commissioning of PARIS cluster(s) on good track IPN Orsay experiment (Spring 2013) as a first step Next step: AGATA@GANIL campaign? Large M γ environment? PARIS for prompt fission fragments calorimetry for applied and fundamental issues in n-induced fission

16 EXTRAS

17 Phoswich delivery : Time table and status Available by now (7): 2 in France (1 IPNO, 1 IPHC) 3 in Poland (Krakow) 2 in India (TIFR) Arriving by the end of the year (7): 1 in France (IPNL) 1 in Turkey 2 in Poland (via Dubna) 1 in Italy 2 in England (Surrey) Arriving from January to April 2013 (10): 8 in France (3 IPNO, 2 GANIL, 2 IPHC, 1 IPNL) 2 in India (BARC) This makes a total of 24 phoswichs (2 clusters and 6 phoscwichs) for IPNO test. Courtesy Iolanda Matea

18 Neutron-induced fission of U8 (ERINDA) Courtesy Jon Wilson Target related Exp (1): U-238, active mass < 10 g, ~ 5 kbq (8cm from primary target) Exp (2): U-238, active mass < 1.2 mg, ~ 5 Bq, on ultra-thin Pb backing Detection 4 LaBr3 (5 cm x 5 cm x 10 cm) from IPNO 2 LaBr3 (cylindrical 2 inch x 2 inch) from IRMM PARIS cluster (9 phoswichs) About 20cm from the target (to allow rejection of neutron of up to 10MeV) Total gamma-efficiency estimated to about % Count rates Fission rate: 1000/s (σ fiss ~0.5b) Gamma-ray rate: 45/s (M γ ~8 and ε=0.5%)