The DESIR facility at SPIRAL2 DESIR: Désintégration, excitation et stockage d’ions radioactifs (Decay, excitation and storage of radioactive ions) Informal collaboration to promote ISOL beams at SPIRAL2 Result of a SPIRAL2 workshop in July 2005 on ISOL beams at SPIRAL2: - beam handling and beam preparation - LASER spectroscopy - Decay spectroscopy Spokes-person: B. Blank GANIL liaison: J.-C. Thomas Bertram Blank, NUSTAR meeting, 22-24 february 2006

Objectives Traps for beam preparation and trap assisted spectroscopy Setups for laser spectroscopy: Collinear laser spectroscopy and b-NMR  moments, spins, radii etc. Setups to study fundamental interactions:  CVC, CKM matrix: 0+ → 0+ transitions  exotic interactions like scalar or tensor currents MOT trap: electric dipole moments to test CP violation and T violation e.g. with Ra Laser PAUL trap: high-precision magnetic and quadruole moments, radii, spins Decay spectroscopy: p-p correlation, astrophysics, cluster emission, GT strength exotic shapes, halo nuclei etc. solide state phyics and other « applications »

SPIRAL 2 LAYOUT GANIL facility LIRAT LINAG Production building DESIR

Conclusions of the SPIRAL2 Workshop (july 2005) Low energy RIB 1. A new experimental area of about 1500m2 located at the ground floor, dedicated for the experiments with low-energy beams from SPIRAL2 is strongly requested. The new building includes area for the experimental equipments, acquisition and control rooms. 2. A High Resolution mass Separator (HRS) with a resolution of M/M>5000 with a dedicated identification station is absolutely necessary. A separation scheme Low Resolution mass separator → RFQ cooler → HRS is proposed. 3. The low energy radioactive beams should be available for experiments already in the beginning of the operation of SPIRAL 2. The physics program would require both neutron-rich and neutron-deficient beams. 4. More than one production target – ion source station is required to ensure flexible schedule and a possibility for fast change of the mass of radioactive beam. 5. An extension of the current LIRAT beam line in order to take a full benefit of the SPIRAL 1 beams is proposed.

SPIRAL ISOL : IBE + LIRAT Station IBE

Possible extension of LIRAT Multi-beam capabilities (physics program  2011) Tests and development for SPIRAL2 & DESIR LIRAT actuel Spec. b LPC Trap ?

Underground J.-C. Thomas

Possible extension of LIRAT Multi-beam capabilities (physics program  2011) Tests and development for SPIRAL2 & DESIR LIRAT actuel SPIRAL2 1+ n+ Spec. b LPC Trap ? J.-C. Thomas

Spectroscopy of trapped beams Fundamental Interactions Ground-floor Laser Spectroscopy Spectroscopy of trapped beams Decay studies Other purposes Cooling/Bunching Fundamental Interactions J.-C. Thomas

Search for exotic interactions b-n angular correlation requires to measure the recoil ion within the SM x : Fermi fraction; r : GT/F mixing ratio beyond the SM a contains quadratic S and T contributions O. Naviliat-Cuncic et al., LPC Caen

Production and preparation of 6He candidate: (pure GT transition) deduce bn correlation from measurement of b-recoil (recoil with very low energies < 1 keV) 6He+ production at SPIRAL cooling in H2 gas / bunching trapping/measuring LIRAT low energy beam line O. Naviliat-Cuncic et al., LPC Caen

Setup and first results TOF of ions extracted from trap mCP recoil ion detector beta telescope PM plastic scintillator DSSSD beam monitor mCP 6He+ 10cm first b-decay detection RF ON/OFF (V-A theory) O. Naviliat-Cuncic et al., LPC Caen

Search for p-p correlation in b2p decay Two possible decay schemes: sequential → no angular or energy correlation 2He type decay → angular and energy correlation  pairing correlations, nucleon-nucleon interaction…. Possible candidates: 22Al, 23SI, 26P, 27S, 31Ar, 35Ca, 43Cr, 50Ni …. Setup: 6 DSSSD 6 large-area silicon det. g detection beam catcher I. Matea et al., CEN Bordeaux-Gradignan

6 E detectors (b rejection) 3 EXOGAM germanium detectors The setup: Silicon cube 6 DSSSD detectors ( ~75% efficiency) 6 E detectors (b rejection) 3 EXOGAM germanium detectors Removable catcher I. Matea et al., CEN Bordeaux-Gradignan

Study of decay of 31Ar at LIRAT/IBE Proton spectrum Production rate: 0.5 – 1 31Ar per second strong contamination from 33Ar I. Matea et al., CEN Bordeaux-Gradignan

b-NMR at DESIR Applicable to many cases, in particular to light nuclei G. Neyens et al.

Collinear laser spectroscopy and b-NMR F.Leblanc et al. G. Neyens et al. charge radii from isotope shifts (center of gravity) HFS gives magnetic moments (g*I) and Q moments in some cases, one can extract spin b-NMR: g factor and, with HFS, one gets spin

Open to everyone interested Synergies with FAIR/NuSTAR Beam preparation: cooler, traps, trap-assisted spectroscopy (MATS) Laser setups (LASPEC) Neutron detection (NCAP) New types of charged-particle and gamma detectors (e.g. LaBr2) Low-energy beam diagnostics ……. To a large extent the same community!!!! B. Blank, M.J.G. Borge, P. Cambell, F. Herfurth, A. Jokinen, F. Leblanc, M. Lewitowicz, D. Lunney, O. Naviliat-Cuncic, G. Neyens, J.C. Thomas and many more… Open to everyone interested

Wien Filter separator Exp. Hall HRS Ident. CIME n+ 1+ LIRAT beam J.-C. Thomas

SPIRAL2 mass separator review October 2005 Panel Members: Remy Anne, Paul Berkvens, Pierre Bricault (Reporter), Richard Catherall, Tim Giles (absent), Alex Mueller (SPIRAL 2 TAC Chair), André Tkatchenko and Martin Winkler Mandate: Expertise on 3 options (Wien Filter, Brama type and ”Bi-selective”) for the low resolution two-beam mass separator Recommendations: The “Wien filter” approach seems better only because we lack information regarding the use of large beam intensity in electrostatic lenses and the detail of the beam transport between the Wien filter and the mass separator One other option proposed by Remy Anne (during the meeting), in this option the beam from the source is separated in space by a septum and then two beams are produced. On the other hand if this beam splitting appears not viable or one find this is not acceptable to reduce the intensity for the experiment and considering the cost associated with each proposed solution one can consider the addition of a second target station. The primary beam can easily be shared between the two stations using pulsed magnet.