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Present status of MINORCA installation and some ideas of possible physics cases.

Present status of MINORCA installation and some ideas of possible physics cases. Georgi Georgiev for the local initiative group Iolanda Matea , David Verney , Guillaume Mavilla … – IPN Joa Ljungvall , Alain Goasduff , Theo Konstantinopoulos , Stepane Cabaret, Xavier Grave … – CSNSM.

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Present status of MINORCA installation and some ideas of possible physics cases.

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  1. Present status of MINORCA installation and some ideas of possible physics cases. GeorgiGeorgiev for the local initiative groupIolandaMatea, David Verney, Guillaume Mavilla … – IPNJoaLjungvall, Alain Goasduff, Theo Konstantinopoulos, Stepane Cabaret, Xavier Grave …– CSNSM

  2. Overview • High-efficiency and high-performance g-ray array – a must for any nuclear spectroscopy laboratory. What is presently available array at ALTO? – ORGAM: 20+ coaxial Ge detectors of Euroball phase 1 – talks IolandaMatea & Alain Goasduff • What could be achievedby combining Miniball and ORGAM arrays in Orsay – MINORCA (MINiball&ORgamCampaign at ALTO) – talk JoaLjungvall • Few examples how MINORCA could contribute to the physics program at ALTO • (Time Dependent) Recoil In Vacuum – a method that could yield high precision g-factor results for both stable and radioactive beams • How MINORCA could contribute to the following Miniball campaigns at HIE-ISOLDE? • An idea for extreme g-ray spectroscopy (in the second well) – is it doable? • How far are we with the installation of MINORCA? – electronics, mechanics, DAQ • What still needs to be worked out and discussed with the user community? • What is the timing? (April 2014  Miniball @ HIE-ISOLDE?)

  3. Electron-nuclear spin interaction in vacuum Target recoil beam (qp,fp) scattered beam ion -ray emitted at angle (qg,fg) - electron spin - nuclear spin attenuation coefficients – a measure for the electron – nuclear spin interaction interaction frequency - depends on I and J – single frequency for J=1/2

  4. Time Dependent Recoil In Vacuum on H-like ions (stable beams) D=T H-like ions attenuation factor J electronspin (random) FF’  |g| F = I + J -array target beam Inuclearspin (aligned) thick stopper R.F. Horstmanet al., Nucl. Phys. A248, 291 (1975) • magnetic field for H-like ions – can be calculated from first principles! • pure H-like charge state could not be achieved

  5. TDRIV – radioactive beam geometry -array D=T F = I + J J electron spin reset foil target FF’  |g| beam 24Mg@120 MeV Inuclear spin particledetector A.E. Stuchbery et al., Phys. Rev. C71, 047302 (2005).

  6. TDRIV @ ALTO with ORGAM Plasticscintilator ORGAM array beam: 24Mg @120 MeV, 1.8 pnA intensity target: 2.4 mg/cm293Nb reset foil: 1.7 mg/cm2 197Au g(2+) • 13 HPGe @ = 46.5, 72.1, 85.8, 94.2, 108.0,133.6, 157.6 • 8-fold segmented annular detector OUPS

  7. Experimental spectra 24Mg

  8. Experimental results • Result consistent with previous g-factor measurement of g(2+) 24Mg TDRIV on H-like ions possible with radioactive beams • The high granularity of Miniball could provide superior results in two ways: • Separation of the “flight” and “reset” components of the gamma line (not resolved in the present experiment) • More sensitive combinations for the particle-gamma correlations <3% uncertainty precise absolute distance definition • v/c = 0.09180.0012 • B1s =29.08019 kT • = 31.5o • gfactor = 0.5280.012(%2.2) preliminary

  9. TDRIV on Na-like ions N-SI-63 A.E. Stuchbery Could a predominant frequencybe observed?

  10. Lifetime measurements with MINORCA? • Orsay Universal Plunger System (OUPS) – for picosecond time range Stand alone or in combination with particle detector?  segmented plastic scintillator or more sophisticated Si detector (CD detector?)? • Combination of high-efficient MINORCA array with a (large) number of LaBr3 detectors – simultaneous coverage of picosecond-to-nanosecond ranges • Test of HIE-ISOLDE plunger at MINORCA?

  11. g-ray spectroscopy in the second well? • half-lives – in the nanosecond region (from few ps up to few ms) • superdeformed states – measured quadrupole moments of 236mPu (NPA 282(77) 77)and 239mPu (PRL 38(77) 387) give major axes ratio of 2:1 • rotational bands observed in even-even isotopes • isomeric-to-ground state population probability (i/ g ~ 10-4) depends only onthe barriers (EA, EB) and isomeric state (EII) energies, and not on the production mechanisms • isomeric g-factor measurements 237m1,m2Pu, 239mAm Superdeformed states in the second minimumdecaying through the outer barrier (EB) via fission Island of fission isomers Very scarce information on single-particle properties

  12. A possible approach • Rotational band in the second minimum – providing an information on (gK – gR) through branching ratios • Advantage of rotational band measurement – no paramagnetic corrections from the implantation • 243Cm (N=147)238U (9Be, 3n) 243Cm ~1.2 mb (gs)232Th (14C, 2n) 243Cm ? mb • “Thick target” (~1 mg/cm2) plusparticle detection around  high prompt fission rate OR? • “Thin target” (~0.2 mg/cm2) plus recoil detection of delayed fission in a particle-detector barrel “zero” prompt fission background IMP, Lanzhou

  13. How MINORCA could contribute to the following Miniball campaigns at HIE-ISOLDE? • Tests with stable beams in experimental conditions similar to those @ HIE-ISOLDE, e.g. angular distributions • Multi-step Coulomb excitation giving access to rotational bands in odd-mass nuclei (97Rb and 99Rb) Preliminary

  14. Present status of MINORCA installation • Miniballelectronics – transported to Orsay and installed in the experimental area • Miniball mechanical support frame – transported from Cologne to Orsay • Combined MINORCA support design being finalized. The order for manufacturing to be finalized by end November

  15. MINORCA support Stephane Cabaret (CSNSM)Philippe Rosier (IPN) ORGAM beam Miniball OUPS plunger, segmented particle detector and/or other(?), readily installed in the vacuum chamber, possibility of installing a large number of LaBr3 detectors

  16. Data Acquisition system • Transfer of the Miniball DAQ from MBS2 to MBS6 – in progress - Rudi Lutter (Munich) • Combining the Miniball DAQ (“triggerless”) with the Orsay (“triggered”) DAQ – Xavier Grave et al. (CSNSM) • To be discussed and a solution found – readout of DGF’s at high count rates (continuous) stable beams

  17. Ancillary (particle) detectors? • 8-fold segmented plastic scintillator – annular detector at variable distance from the target • CORSET – fission-products detector (mass resolution ~ 3-4) • a CD detector – could it stand the stable-beam intensity? • another particle detector?

  18. Response of the Minibal detectors to high count rate and neutron flux? • What are the count rates at which the Miniball detectors can run safely? (bottle-neck for some physics cases) • Control of the neutron flux per Miniball detector during measurements? (neutron detector in the array?) • Procedure for determination of the neutron dose already observed by the detectors • Procedure for annealing of the detectors

  19. Planning • MINORCA ready for experiments by April 2014 • Call for proposals at ALTO – already sent (25 Sept.); Deadline for proposals – 21 December 2013; PAC – in January 2014 • Please contact us to discuss the configurations and detectors that you need for your experiment • IolandaMatea (matea@ipno.in2p3.fr) • GeorgiGeorgiev (georgi.georgiev@csnsm.in2p3.fr)

  20. Yourideas for the use of MINORCA are WELCOME!

  21. Ge_single ( = 94.2 o) 197Au 5/2+ 3/2+ 24Mg 511 24Mg 2+ 0+ 93Nb 2+ 0+ Partical –Gamma Coincidence Ge4_P2 197Au 5/2+ 3/2+ 511 24Mg 2+ 0+ 93Nb

  22. Coulex with Miniball

  23. What Miniball is? 8 triple cluster6-fold segmentedGe tapered detectors

  24. How the detectors are put together? • High flexibility support frame that allows precise positioning of the 8 clusters at “any” angle(frame available at CERN)

  25. The Coulex configuration at REX-ISOLDE 8 triple clusters in a compact geometry around a spherical vacuum chamber Vacuum chamber- 6 position targetframes - Segmented part.detector Particle detector(16 strips x 24 sectors) covering angles between Q = 17° – 54°

  26. The transfer reaction configuration – T-REX Position sensitive CD-like (strip) detectors in forwardand backward directions Position sensitive (barrel, resistive layer) for anglesclose to 90°

  27. What has already been done with Miniball at REX-ISOLDE

  28. What could be achieved? • High gamma-ray efficiency – possibilities of performing “more exotic” experiments with the available (stable) beams • Orsay plunger (OUPS) • Fast timing detectors – could become available • other ancillary detectors … • High granularity (angular definition) of Miniball – still to be explored for angular correlations • Test bench for approaches and techniques to be used (with the same spectrometer) with radioactive beams

  29. What has been done? GEANT simulations – JoaLjungvall 15+ ORGAM anti-Compton shieldedGe detectors x 0.1% 8 Miniball triple cluster detectorsat @ 14 cm from target with addbackwithout Compton shield Efficiency at 1332 keV: 6.3% - Miniball 1.8% - 15 ORGAM Ge’s TOTAL  8.1% anti-Compton shields could be of high interest for the Miniball detectors

  30. What still needs to be done? • Combine the support frame of Miniball with the one of ORGAM – on the way Stephane Cabaret (CSNSM) and Philippe Rosier (IPN)

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