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Light element studies Structure of transfermium nuclei

Light element studies Structure of transfermium nuclei. Darek Seweryniak on behalf of ANL, Lowell, Jyvaaskyla, Maryland, Orsay, … collaboration Argonne National Laboratory ATLAS User Workshop, May 15-16, 2014. Heavy element studies Structure of transfermium nuclei. Darek Seweryniak

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Light element studies Structure of transfermium nuclei

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  1. Light element studiesStructure of transfermium nuclei Darek Seweryniak on behalf of ANL, Lowell, Jyvaaskyla, Maryland, Orsay, … collaboration Argonne National Laboratory ATLAS User Workshop, May 15-16, 2014

  2. Heavy element studiesStructure of transfermium nuclei Darek Seweryniak on behalf of ANL, Lowell, Jyvaaskyla, Maryland, Orsay, … collaboration Argonne National Laboratory ATLAS User Workshop, May 15-16, 2014

  3. Super-Heavy Nuclei Cold fusion with 208Pb, 209Bi targets GSI, LBNL, Riken Hot fusion with 48Ca beamsDubna/LLNL, GSI, LBNL In-beam, K-isomers, a-decay fine structure ANL, Dubna, GSI, JYFL, LBNL Chart courtesy of Y. Oganessian

  4. Outline • Physics • Discrete in-beam g-ray spectroscopy - moments of inertia, alignment • in-beam g-ray calorimetry – fission barriers • K-isomers – single-particle energies • Decay spectroscopy – alpha decay Q-values, spontaneous fission lifetimes • Cooled beams • Precision mass measurements • Laser spectroscopy • SHE formation (W. Loveland) • Equipment • Fragment Mass Analyzer + GS • AGFA + DGS/GRETINA (higher efficiency x 10 , higher rates x 5) • intense beams from ATLAS (~1 pmA) ATLAS User meeting, May 15-16, 2014

  5. Discrete in-beam spectroscopy 256Rf JUROSPHERE+RITU P. Greenlees et al., PRL 109, 012501 (2012) ATLAS User meeting, May 15-16, 2014

  6. In-beam spectroscopy “above” K-isomers 8- isomer in 252No JUROSPHERE+RITU 7/2+[624]n X 9/2-[734]n assignment B. Sulignano et al., PRC 186, 044318 (2012) ATLAS User meeting, May 15-16, 2014

  7. In-beam g-ray calorimetryHK entry point distributions 254No 223 MeV 254No 219 MeV GS+FMA Direct fission barrier measurement (if below neutron separation energy) 220Th G. Henning et al., submitted to PRL ATLAS User meeting, May 15-16, 2014

  8. Discovery of K-isomers in 254Rfexperiments with FMA and BGS using digital DAQ CE-CE event 4qp 400 ms CE 4 ms 2qp CE implant-CE-sf event 254Rf gs 25 ms sf J. Chen, H. David, F. Kondev, D.S. et al. ATLAS User meeting, May 15-16, 2014

  9. SHE spectroscopy TASCA at GSI X-ray detection along the element Z=115 alpha decay chain as means to determine the atomic number D. Rudolph et al., PRL 111, 112502 (2013) ATLAS User meeting, May 15-16, 2014

  10. Cool beams of heavy nuclei 253No SHIPTRAP at GSI Heavy reaction products can be stopped in a gas cell at the focal plane of AGFA, cool ed in RFQ and send to a Penning Trap. Laser spectroscopy can be also possible (P. Mueller) M. Block et al., Nature 463 785 (2010) ATLAS User meeting, May 15-16, 2014

  11. Experimental requirements To study heavier nuclei we need more beam, higher efficiency, faster detectors • DGS – high rates (x5) • GRETINA – high rates (x5), large FMA solid angle (x4), Doppler correction • AGFA – higher efficiency (x10), • digital implantation-decay station – fast activities • ATLAS intensity upgrade (x3 better beam transmission) • VENUS ECR source (x5 more intense beams) • Detection improvements • 10x10 cm2 DSSD • in-beam CE detector ATLAS User meeting, May 15-16, 2014

  12. Need a much easier way to move Gammasphere between the two beam lines for experiments or to avoid neutron damage during high intensity experiments. It will make placing GRETINA on any of the two much easier as well. ATLAS User meeting, May 15-16, 2014

  13. Thank you for your attention. ATLAS User meeting, May 15-16, 2014

  14. ATLAS User meeting, May 15-16, 2014

  15. Argonne Tandem Linac Accelerator System Beams from protons to Uranium with energies 10MeV/nucleon+ See talk by Richard Pardo on Friday about radioactive beams ATLAS User meeting, May 15-16, 2014

  16. Argonne Fragment Mass Analyzer C. N. Davids et al., Nucl. Instr. Meth., B 70, 358 (1992). ATLAS User meeting, May 15-16, 2014

  17. Argonne Fragment Mass Analyzer Q1 Mass resolution: dM/M~1/350 Angular acceptance: DW=8 msr(2 msr) Energy acceptance: DE/E=+/-20% M/Q acceptance: D(M/Q)/(M/Q)=10% Flight path 8.2m Max(Br)=1.1Tm Max(Er)=20MV Can be rotated off 0 degrees Can be moved along the axis Different focusing modes Q2 ED1 MD ED2 Q3 Q4 ATLAS User meeting, May 15-16, 2014

  18. GAMMASPHERE+FMA Important component of the experimental program at ATLAS since its commissioning in 1993 (~200 papers) • 101Sn • Proton drip-line • Proton emitters • new a emitters • In-beam g rays • Transfermium nuclei: No, Lr, Rf • Transfer on 56Ni and 44Ti • … Fusion-evaporation, deep-inelastic, transfer reactions ATLAS User meeting, May 15-16, 2014

  19. ATLAS efficiency and intensity upgrade • new positive ion injector (undergoing) • Two new cry modules (summer 2013) • Energy upgrade cryomodule (proposed) • high intensity ECR source (planned) ATLAS User meeting, May 15-16, 2014

  20. Preparation for high intensity ATLAS beams Currently beams ~10 pnA, event rates ~1kHz Future experiments ~100 pnA (1pmA), event rates 10kHz(100kHz) • FMA upgrades • New beam dump (completed) • New entrance quadrupole doublet (design) • Focal plane detector upgrades • Large-area high-resolution micro-channel plate detector (in progress) • High granularity DSSD (completed) • DAQ • Digital DAQ (completed) • Argonne Gas-Filled Separator (design) ATLAS User meeting, May 15-16, 2014

  21. New beam dump • Segmented anode was installed in 2002 • However, beam used to strike the inside of the anode and the tank near the exit relatively close to the electrodes • A suppressed beam dump was placed outside of the tank 1st electric dipole ATLAS User meeting, May 15-16, 2014

  22. New ED1 tank ATLAS User meeting, May 15-16, 2014

  23. Faraday Cup • Slit in the tank wall • Beam dumped on a Ta plate • Entrance slit kept at positive potential with respect to the Ta plate to suppress electrons knocked out of the plate ATLAS User meeting, May 15-16, 2014

  24. New entrance quads • 1st quad shorter with larger tip field • similar concept was used in EMMA • Increases the solid angle from 8 msr to 12 msr at 30 cm between target and FMA • Only small gain at 90 cm Courtesy of B. Davids ATLAS User meeting, May 15-16, 2014

  25. FMA at 293 mm OLD: Qy=0.038 rad Qy,max=0.0401 rad NEW: Qy=0.060 rad Qy,max=0.0634 rad Qx=0.046 rad Qx,max=0.0495 rad Qx=0.059 rad Qx,max=0.0591 rad W=7.4 msr W=11.8 msr ATLAS User meeting, May 15-16, 2014

  26. Resistive readout 3 mcp’s foil e HI from FMA magnet Large-area high-resolution micro-channel plate focal plane detector detector • Large area to cover the whole focal plane (4X12 cm2) • Position resolution < 1mm • High rate capabilty (100 kHz) • Three micro channel plates for large multiplication Photonis Inc., USA Permanent magnets to limit diffusion of electrons to achieve better position resolution D.Shapira etal., Nucl. Instr. and Meth. in Phys. Res. A 454 (2000) 409 ATLAS User meeting, May 15-16, 2014

  27. High-granularity implantation-decay DSSD 160x160 strips64mm x 64 mm100, 140, 1000 mm thick ATLAS User meeting, May 15-16, 2014

  28. X-array • 5 clover detectors in a box geometry • 64x64 mm, 160x160 DSSD • Mobile frame ATLAS User meeting, May 15-16, 2014 28

  29. FMA Digital DAQ(based on GRETINA) • trigerless • DSSD (320 chans) • X-array (20 chans) • focal plane (20 chans) • Resolution comparable to analog 100Mhz, 14-bit Digitizer M. Cromaz et al., A 597 (2008) 233–237 Trigger and Time control module J.T. Anderson et al., 2007, IEEE Nuclear Science Symposium Conference Record, p. 1751 ATLAS User meeting, May 15-16, 2014

  30. Argonne Gas-Filled Separator - AGFA 1B.B. Back, 1R.V.F. Janssens, 1W.F. Henning, 1T.L. Khoo, 1J.A. Nolen, 1D.H. Potterveld, 1G. Savard, 1D. Seweryniak, 3M. Paul, 2P. Chowdhury, 4W.B. Walters, 5P.J. Woods, 6K. Gregorich 1Argonne National Laboratory, Argonne, 2University of Massachusetts Lowell, 3Hebrew University, 4University of Maryland, 5University of Edinburgh, 6Lawrence Berkeley National Laboratory • Use combined-function magnets • Overlapping bending, focusing fields • Fewer magnets, ultra compact design • Innovative QvDm design • Design parameters • 33o bend • 22.5 msr at 80 cm (42 msr at 40 cm) • 2.5 Tm • 4.0 m total length (3.6 m at 40 cm) • 80 cm target-separator (Gammasphere) • 40 cm (stand-alone) • Compact focal plane(~5cm x 5 cm) ATLAS User meeting, May 15-16, 2014

  31. AGFA optics and parameters V. rays ± 102 mrad H. rays ± 52 mrad ATLAS User meeting, May 15-16, 2014

  32. AGFA – 3D magnet design ATLAS User meeting, May 15-16, 2014

  33. 254No test case Simulations still undergoing ATLAS User meeting, May 15-16, 2014 48Ca + 208Pb → 254No + 2n Ebeam = 220 MeV 1 Torr He, 5 x 2 mm beam spot 254No angular distr: Gaussian, σ = 51 mrad 48Ca stripped, (C foil) qbar = 17.1 89% of 254No transported to focal plane 71% fall within a 64 x 64 mm2 DSSD Solid angle to DSSD is 22 msr Beam is well separated

  34. Focal plane distribution ATLAS User meeting, May 15-16, 2014

  35. ATLAS User meeting, May 15-16, 2014

  36. Separator for Unique Products of Experiments with Radioactive Beams - SUPERB A.M. Amthor1, A. Drouart2, S. Manikonda3, J. Nolen3, H. Savajols4, D. Seweryniak3 1Bucknell University, 2CEA-DSM/Irfu/SPhN, 3Argonne National Laboratory, 4GANIL Based on the design of the mass separator section of S3 optimized for experiments with reaccelerated radioactive beams at Rea12 T 3QS ED 3QS • A charge state acceptance : ± 10% • A Bρ acceptance for each charge state: ± 10% • A large angular acceptance in both planes: +/- 50 mrad • A magnetic rigidity Bρmax = 1.5 Tm • An electric rigidity Eρmax = 10 MV (2nd set of electrodes for higher electric rigidity) • A mass resolution of 1/300 (FWHM) • A primary beam suppression not critical 3QS MD 3QS FP ATLAS User meeting, May 15-16, 2014

  37. SUPERB – 1st order calculations 58Ni+46Ti reaction X-Z plane X-Y distribution at the focal plane for 5 charge states/3 masses Y-Z plane ATLAS User meeting, May 15-16, 2014

  38. Conclusions • FMA is almost ready to accept high-intensity beams from ATLAS • AGFA will complement FMA for experiments with heavy nuclei • SUPERB combines advantages of FMA and AGFA for experiments with reaccelerated radioactive beams ATLAS User meeting, May 15-16, 2014

  39. Thank you for your attention! ATLAS User meeting, May 15-16, 2014

  40. ATLAS User meeting, May 15-16, 2014

  41. ATLAS User meeting, May 15-16, 2014

  42. Argonne Gas-Filled Separator - AGFA 1B.B. Back, 1R.V.F. Janssens, 1W.F. Henning, 1T.L. Khoo, 1J.A. Nolen, 1D.H. Potterveld, 1G. Savard, 1D. Seweryniak, 3M. Paul, 2P. Chowdhury, 4W.B. Walters, 5P.J. Woods, 6K. Gregorich 1Argonne National Laboratory, Argonne, 2University of Massachusetts Lowell, 3Hebrew University, 4University of Maryland, 5University of Edinburgh, 6Lawrence Berkeley National Laboratory • Large solid angle >15 msr • Operation with Gammasphere (80 cm from target to 1st magnet) • Can be operated stand-alone for larger solid angle (40 cm to 1st magnet) • Bρ ≤ 2.5 Tm • Good primary beam suppression • Large bend angle • Small focal spot to enable efficient measurements • Excellent focus in vacuum mode • Short flight path to minimize growth due to multiple scattering • Small dispersion <x,δ> (cm per percent deviation in Bρ) • Cost less than $2M ATLAS User meeting, May 15-16, 2014

  43. Target spot ± 0.5 mm in x and y with ± 50 mrad in both dimensions • Momentum acceptance ± 5% for each charge state, charge-state acceptance ± 10% , and mass range ± 10%. • Fully achromatic in momentum for each m/q value. • The first half contains an electrostatic dipole that creates an energy-dispersive focal plane. • For symmetric fusion-evaporation reactions the electric rigidities are less than 10 MV, • The second half consists of a magnetic dipole section. • The m/q focal plane is approximately 12-cm wide by 2-cm tall ATLAS User meeting, May 15-16, 2014

  44. X-array • 5 clover detectors in a box geometry • 64x64 mm, 160x160 DSSD ATLAS User meeting, May 15-16, 2014

  45. AGFA - Design criteria ATLAS User meeting, May 15-16, 2014 • Large solid angle >15 msr • Operation with Gammasphere (80 cm from target to 1st magnet) • Can be operated stand-alone for larger solid angle (40 cm to 1st magnet) • Bρ ≤ 2.5 Tm • Good primary beam suppression • Large bend angle • Small focal spot to enable efficient measurements • Excellent focus in vacuum mode • Short flight path to minimize growth due to multiple scattering • Small dispersion <x,δ> (cm per percent deviation in Bρ) • Cost less than $2M

  46. In some experiments the transmission is more important than the mass separation (for example SHE) • Gas-filled separators have larger angular acceptance and collect all charge states resulting in ~x5 larger transmission • Gas-gilled separators are complementary to vacuum mass separators ATLAS User meeting, May 15-16, 2014

  47. FMA Digital DAQ status • The system was already used in several experiments last spring • stand-alone FMA • Conversion electrons and fission • alpha decay • GAMMASPHERE+FMA • Beta-decay tagging • Proton-decay tagging ATLAS User meeting, May 15-16, 2014

  48. FMA Digital DAQ TS Router IOC 4XDIG IOC 4XDIG IOC 4XDIG network switch CPU IOC master TTC + 2 router TTC disk • Based on the GRETINA DAQ • DSSD - 320 channels • X-array – 20 channels • focal plane – 20 channels . ATLAS User meeting, May 15-16, 2014

  49. X-array ATLAS User meeting, May 15-16, 2014

  50. DSSD chamber with preamps ATLAS User meeting, May 15-16, 2014

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