Division Accélérateurs Radioactive Beam Production by Photofission Alex C. Mueller, Accelerator Division, IPN ORSAY, CNRS/IN2P3 (Seminar at the CERN PS-Division, June 13, 2001) Division Accélérateurs Introduction Scientific Motivation Making Radioactive Beams Considerations on the Intensities X-sections for Fission Fragments The PARRNe R&D Programme PARRNe-1 at the LEP-injector Experimental Results Concluding Outlook Alex C. Mueller, CERN PS-Div., June 2001, T 1

Division Accélérateurs Nuclei far from stability key objects in for the nucleosynthesis in the universe Division Accélérateurs Nova explosion proton-rich nuclei Supernova explosion neutron-rich nuclei Gravitational collapse of a massive star to a neutron star "neutron-matter" simulating systems Alex C. Mueller, CERN PS-Div., June 2001, T 2

Division Accélérateurs Nuclear Forces and the Nuclear Many-Body Problem Division Accélérateurs The view of the Polish/US theoretical nuclear physicist Witold Nazarewicz: light nuclei light nuclei medium-mass medium-mass Radioactive Beam Facilities and heavy nuclei and heavy nuclei nucleon nucleon effective effective NN force NN force ALICE @LHC free NN free NN force force Derivation of the effective NN force Derivation of the in nuclear medium quarks & gluons quarks & gluons bare NN force CEBAF, ELFE from QCD Alex C. Mueller, CERN PS-Div., June 2001, T 3

Chemistry and Physics of the heaviest elements Division Accélérateurs The colors in the figure below correspond to the binding energy ("shell stabilization), hence to the life time. In the dark blue region the lifetime may reach years or more. Fusion Reactions with neutron-rich beams, like 132Sn, might give acces to this region Alex C. Mueller, CERN PS-Div., June 2001, T 4

Radioactive Beams also have a number of Applications (examples from CERN-ISOLDE Webpage) Division Accélérateurs Division Accélérateurs Alex C. Mueller, CERN PS-Div., June 2001, T 5

Division Accélérateurs The Two Production Methods for Radioactive Beams and their combination, "RIA" proposed in the US Division Accélérateurs "In-Flight" RIA, combining ISOL & In-Flight ISOL = Isotopic Separation On-Line Alex C. Mueller, CERN PS-Div., June 2001, T 6

An ISOL facility including post- acceleration: SPIRAL phase I Division Accélérateurs - Driver (GANIL cyclotrons) - Target-ion source system - Post-accelerator cyclotron CIME - I up to 109 pps - Mass range: up to A=100 Into operation by summer 2001 Alex C. Mueller, CERN PS-Div., June 2001, T 7

Secondary radioactive beam intensities Division Accélérateurs Alex C. Mueller, CERN PS-Div., June 2001, T 8

An example for nuclear reaction cross sections (fission) Division Accélérateurs (Calculations: Ridikas, ENAM 98) Alex C. Mueller, CERN PS-Div., June 2001, T 9

Optimising the Production Division Accélérateurs In-Flight : get F large  high-power accelerator R&D get N large  high-energy > 1 GeV get e4 large  high-energy > 1 GeV ISOL : get F large  high-power accelerator R&D get e1e2e3 large  R&D on target and ion-sources, like PARRNe Alex C. Mueller, CERN PS-Div., June 2001, T 10

Limits of the ISOL technique: power deposit in the target Division Accélérateurs Pic de Bragg distance de parcours dans la cible dE/dx Inconvénient des faisceaux intenses de particules chargés : ralentissement des particules  dépôt d’énergie localisée en fin de parcours (pic de Bragg) Utilisation des neutrons : toute l’énergie incidente est dissipée dans la réaction nucléaire Neutrons rapides :  238U utilisable Neutrons thermiques :  réacteur nucléaire  235U Alex C. Mueller, CERN PS-Div., June 2001, T 11

ISOL at the highest power levels Division Accélérateurs One stage : direct use of charged particles, minimize dE/dx (low Z, high E at 1 GeV max. 100 - 200 kW Two stage : use neutral particles in second stage, i.e. neutrons & photons for neutrons 5 MW of proton beam (like spallation source) RIA (fragmentation + gas collec- tion scheme) is also in this class Alex C. Mueller, CERN PS-Div., June 2001, T 12

Original Motivation for Spiral-II Division Accélérateurs A new driver: d (60 - 200 MeV) with high intensity I = 50 - 200 mA Dedicated cyclotron or GANIL SSC fission induced by neutrons Fission products accelerated in CIME cyclotron 90Kr, 132Sn I > 101O pps Alex C. Mueller, CERN PS-Div., June 2001, T 13

High Intensity Linacs for future ISOL Facilities Division Accélérateurs "Generic" lay-out for the EURISOL project note similarity with other projected linacs n factory (CERN SPL) nuclear waste trans- mutation Neutron Spallation Source (SNS, ESS) Material Irradiation Target R&D needed, justification of the PARRNE programme for fission fragment production Alex C. Mueller, CERN PS-Div., June 2001, T 14

PARRNe-1 (European RTD: IPN-Jyväskylä-Louvain-GANIL-KVI) Division Accélérateurs Alex C. Mueller, CERN PS-Div., June 2001, T 15

PARRNe-2 at the Orsay Tandem Division Accélérateurs Targets UCx Molten U + Sources Nier Bernas Isolde MK5 Alex C. Mueller, CERN PS-Div., June 2001, T 16

Elements already produced with PARRNe-2 (>100 isotopes) Division Accélérateurs Alex C. Mueller, CERN PS-Div., June 2001, T 17

Present Rates with PARRNe-2 (here upper fission hump) Division Accélérateurs Alex C. Mueller, CERN PS-Div., June 2001, T 18

Photo-fission: the idea and involved processes Division Accélérateurs Convertisseur Cible 238UCx  e- Photo-electric effect Diffusion (Compton, Raleigh) Pair Production (e+e-) Nuclear Reactions (, f) GDR (Giant Dipolar Resonance) (, n) (, 2n) Bremsstrahlung Ionisation excitation Alex C. Mueller, CERN PS-Div., June 2001, T 19

Production of photons by Bremsstrahlung and X-section for photofission Division Accélérateurs e- g a 2-3o Data compiled by Yu.Ts. Oganessian JINR-E7-2000-83 Fission probability: 0.6%/e @ 50 MeV! . Alex C. Mueller, CERN PS-Div., June 2001, T 20

Distribution of the produced nuclei in Photofission Division Accélérateurs Alex C. Mueller, CERN PS-Div., June 2001, T 21

The set-up of the CERN experiment Division Accélérateurs Alex C. Mueller, CERN PS-Div., June 2001, T 22

Location of the converter and the target Alex C. Mueller, CERN PS-Div., June 2001, T 28

The experiment: cryogenic collection and data acquisition Division Accélérateurs Alex C. Mueller, CERN PS-Div., June 2001, T 24

Division Accélérateurs A typical g-spectrum from the radioactive decay from the collected fission fragments Division Accélérateurs Alex C. Mueller, CERN PS-Div., June 2001, T 25

Results @ CERN and comparison with fast-neutron data Division Accélérateurs Without Conv. KVI 80 MeV D 4 cm Conv. 8 cm Converter Alex C. Mueller, CERN PS-Div., June 2001, T 26

Inspection of the target after irradiation Division Accélérateurs Alex C. Mueller, CERN PS-Div., June 2001, T 27

SPIRAL-II and other projects Division Accélérateurs Dubna: DRIBS project, under construction Chalk River: theoretical Study by W.T. Diamond SPIRAL-II: here with photofission Alex C. Mueller, CERN PS-Div., June 2001, T 28

Division Accélérateurs Perspectives Division Accélérateurs Complete R&D Programme with the LPI front-end and PARRNe-2 SPIRAL-2 (Scientific&Technical Proposal presently under evaluation The "ultimate" EURISOL electron driver Figure 3  20 m long Alex C. Mueller, CERN PS-Div., June 2001, T 29

Spallation vs. Photofission from Division Accélérateurs Alex C. Mueller, CERN PS-Div., June 2001, T 30

Conclusion of the first part… Division Accélérateurs Alex C. Mueller, CERN PS-Div., June 2001, T 31