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Alexander Herlert High-precision mass measurements on exotic nuclides: recent results from the ISOLTRAP experiment CERN, PH-IS EP Seminar, CERN, May 15,

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Presentation on theme: "Alexander Herlert High-precision mass measurements on exotic nuclides: recent results from the ISOLTRAP experiment CERN, PH-IS EP Seminar, CERN, May 15,"— Presentation transcript:

1 Alexander Herlert High-precision mass measurements on exotic nuclides: recent results from the ISOLTRAP experiment CERN, PH-IS EP Seminar, CERN, May 15, 2006

2 High-precision mass measurements on exotic nuclides: recent results from the ISOLTRAP experiment EP Seminar, CERN, May 15, 2006 Atomic masses of radionuclides The ISOLTRAP experiment Principle of mass measurement Recent experimental results New techniques and methods

3 Radionuclides - What accuracy is needed? Nuclear Physics nuclear binding energies, Q-values shell closures, pairing, deformation, halos, isomers test of nuclear models and formulae  m/m  1·10 -7 Astrophysics nuclear synthesis r- and rp-process  m/m  1·10 -7 Weak Interaction symmetry tests CVC hypothesis  m/m  1·10 -8 ( p, )  ( p, )  ( p, )   +  +  + Hot cycle Cold cycle Common 11 Li

4 Neutron Number N Proton Number Z In total: 3180 nuclides Measured masses: 2228 Atomic Mass Evaluation 2003 all nuclides G. Audi, A.H. Wapstra, C. Thibault, Nucl. Phys. A 729

5 Neutron Number N Proton Number Z In total: 1158 nuclides Atomic Mass Evaluation 2003  m/m < 10 -7 G. Audi, A.H. Wapstra, C. Thibault, Nucl. Phys. A 729

6 Neutron Number N Proton Number Z In total: 181 nuclides Atomic Mass Evaluation 2003  m/m < 10 -8 G. Audi, A.H. Wapstra, C. Thibault, Nucl. Phys. A 729

7 Neutron Number N Proton Number Z 133,134 Cs 85,87 Rb In total: 24 nuclides Atomic Mass Evaluation 2003  m/m < 10 -9 G. Audi, A.H. Wapstra, C. Thibault, Nucl. Phys. A 729

8 See: Lunney, Pearson & Thibault, Rev. Mod. Phys. 75 (2003) Mass measurement programs for radionuclides worldwide

9  operating facilities  facilities under construction or test  planned facilities  TRIUMF Argonne   MSU  Jyväskylä GSI  Stockholm   LBL SHIPTRAP HITRAP ISOLTRAP REXTRAP ATHENA ATRAP WITCH JYFL TRAP SMILETRAP CPT LEBIT RETRAP TITAN MAFF TRAP  Munich CERN  RIKEN TRAP Penning traps at accelerators

10 Production of radioactive nuclides at ISOLDE

11

12 ISOLTRAP: Experimental setup buncher preparation trap precision trap 2m

13 B = 4.7 T B = 5.9 T 2 m G. Bollen, et al., NIM A 368, 675 (1996) F. Herfurth, et al., NIM A 469, 264 (2001) determination of cyclotron frequency (R = 10 7 ) removal of contaminant ions (R = 10 5 ) Bunching of the continuous beam ISOLTRAP: Experimental setup

14 B + q/m Principle of mass determination measurement of cyclotron frequency Superposition of strong homogeneous magnetic field weak electrostatic quadrupole field

15 B + q/m motional modes of ion stored in a Penning trap Principle of mass determination measurement of cyclotron frequency

16 Scan QP-excitation freq. rf about c Quadrupole excitation rf Time-of-flight (TOF) radial  axial energy Magnetron excitation Principle of mass determination Conversion of magnetron into cyclotron motion B z Trap MCP Detector passing B-field gradient after ejection

17 TOF spectrummean TOF Principle of mass determination Example: 85 Rb (900ms excitation duration)

18 TOF spectrummean TOF Principle of mass determination fit of theoretical line shape to the data Example: 85 Rb (900ms excitation duration)

19 Principle of mass determination cyclotron frequency of "unknown" nuclide cyclotron frequency of well-known nuclide determination of mass ratio

20 85 Rb 23 Na 39 K 133 Cs Stable alkali ions as mass references

21 C2C2 C3C3 C4C4 C4C4 C5C5 C6C6 C7C7 C8C8 C9C9 C 10 C 11 C 12 C 11 C 12 C 13 C 14 C 15 C 16 C 17 C 18 C 19 C 18 C 19 C 20 C 21 C 22 C1C1 K. Blaum et al., EPJ A 15, 245 (2002) Carbon clusters as mass references

22 Determination of the mass accuracy Combined carbon cluster cross-reference measurements m / u Relative mass accuracy limit: (  m/m) lim  8  10 -9 A. Kellerbauer et al., EPJ D 22, 53 (2003)  m/m / 10 -8

23 ISOLTRAP mass measurements in 2004-2005 71-81 Zn Nuclides measured in 2004/2005 Nuclides measured in 2004/2005 118,120,122-124 Cd 126 Xe, 136 Xe 127,128,131-134 Sn 84 Kr, 86-95 Kr 35-38 K, 43-46 K 17 Ne, 19 Ne 22 Mg 21-22 Na Highlights NuclideHalf-lifeUncertainty 17 Ne 22 Mg 35 K 109 ms 3.86 s 178 ms 530 eV 270 eV 530 eV 81 Zn 290 ms3.45 keV

24 Nucleosynthesis and r-process fusion in stars s-process r-process Sn Pb Ni protons neutrons courtesy: K. Blaum 50 82

25 ISOLDE target for Zn run courtesy: T. Stora et al. UC x target RILIS quartz transfer line protons

26 Yields at ISOLTRAP estimate for target/ion source 0.5%

27 Result for 81 Zn 81 Zn +

28 Preliminary result for mass excess Zn preliminary Zn m = A·m u + ME

29 2n separation energy AME2003 Zn

30 2n separation energy ISOLTRAP AME2003 Zn

31 131 Sn isomer AME2003 G. Audi et al.

32 Removal of contaminants for Sn measurements Sn Sn 34 S 127,128,131-134 Sn isobaric contaminants (Cs) Sn 34 S

33 Preliminary result for mass excess Sn preliminary M. Dworschak et al. 131 Sn ???

34 The mass of 17 Ne lightest nuclide measured at ISOLTRAP two-proton halo candidate: A. Ozawa et al., Phys. Lett B 334, 18 (1994) M.V. Zhukov et al., PRC 52, 3505 (1995) R. Kanungo et al., Phys. Lett. B 571, 21 (2003)

35 AME2003  m < 600 eV The mass of 17 Ne 17 Ne 17 Ne + T 1/2 = 109 ms Yield ISOLDE = 1000/s About 450 ions/h at ISOLTRAP m = A·m u + ME

36 The two-proton halo candidate 17 Ne How to probe if 17 Ne is a proton halo? 17 Ne Isotope-shift measurements: (COLLAPS experiment, Neugart et al.) Mass uncertainty of  m /m  1·10 -7 (~ 2 keV) required!  nuclear charge radii Via the nuclear charge radii!

37 Collaps upper limit Collaps lower limit Finite range Droplet Preliminary result without new mass values PhD thesis W. Geithner

38 Fermi 0 + 0 +  -decays between analog states of spin J  =0 + and isospin T=1 conserved vector current hypothesis: ft = const M V Fermi-matrix element G V coupling constant for semileptonic weak interaction J.C. Hardy and I.S. Towner, Phys. Rev. C 71, 055501 (2005) Conserved vector current (CVC) hypothesis radiative corrections  R and  R isospin not exact symmetry: isospin-symmetry-breaking correction  C

39 Superallowed  -decay nuclides - 9 best known cases experimental data needed: Q BR, t 1/2 f = f (Z,Q) t = f (BR,t 1/2 ) 10 C 14 O 26m Al 34 Cl 38m K 42 Sc 46 V 50 Mn 54 Co T z = -1 T z = 0 statistical rate function partial half-life J.C. Hardy and I.S. Towner, Phys. Rev. C 71, 055501 (2005)

40 I.S. Towner and J.C. Hardy, Phys. Rev. C 66, 035501 (2002) Superallowed  -decay nuclides - 9 best known cases 3072.2(8) s

41 Cabibbo-Kobayashi-Maskawa (CKM) matrix Unitarity 95% 5% 0.001%V ub V ud V us Contribution to the unitarity: Unitarity of CKM matrix weak interaction coupling constant G F from muon decay

42 discrepancy by more than 2  Further experimental data as well as refined calculations of correction terms needed I.S. Towner and J.C. Hardy, Phys. Rev. C 66, 035501 (2002) Unitarity of CKM matrix Result:

43 The mass of 22 Mg 10 frequency ratios measured 16 relations included in  2 adjustment M. Mukherjee et al., Phys. Rev. Lett. 93, 150801 (2004). 22 Mg +

44 Solving the mass discrepancy of 22 Mg 200 eV CPT J. Clark et al. M. Mukherjee et al., Phys. Rev. Lett. 93, 150801 (2004).

45 3072.7(8) s J.C. Hardy and I.S. Towner, Phys. Rev. C 71, 055501 (2005) Updated values F. Herfurth et al., EPJA 15, 17 (2002) A. Kellerbauer et al., PRL 93, 072502 (2004) M. Mukherjee et al., PRL 93, 150801 (2004)

46 V ud (nuclear  -decay) = 0.9738(4) V us (kaon-decay) = 0.2200(26) V ub (B meson decay) = 0.00367(47) Present status: i.e. CKM not unitary at the 98% confidence level (non-)unitarity of CKM-matrix J.C. Hardy and I.S. Towner, Phys. Rev. C 71, 055501 (2005) Updated values for CKM unitarity test V us (K + -decay) = 0.2272(30) 0.9993  0.0011 (Brookhaven E865) V us (K + -decay) = 0.2252(22) (Fermilab E832) new result for V us :

47 Outlook for CKM unitarity test T z = -1 T z = 0 extend investigation to other nuclides increase precision on nine best ft-values

48 J.C. Hardy and I.S. Towner, Phys. Rev. C (2005) Outlook for CKM unitarity test

49 New experimental methods and technical development How to improve ISOLTRAP ?

50 New ion sources new ion source Pierre Delahaye

51 New ion sources carbon cluster ion source Nd:YAG Manas Mukherjee

52 Preparation of ions - removal of isobaric contaminants cooling resonance of 41 K + removal of 39 K + by dipolar excitation

53 New detection schemes excitation with Ramsey technique Sebastian George

54 Drift tube Window (open access) Channeltron detector Spare MCP detector Feed- through Ions from the precision trap New detector setup

55 Detection efficiency MCP Detection efficiency Channeltron Better statistical uncertainty  30%  90% Get access to shorter- lived nuclides (  50mm) (  12mm) MCP Comparison of efficiency MCP/Channeltron

56 new detector CEM MCP Number of Ions per Pulse Time / ms Comparison of efficiency

57 Stabilization of magnetic field temperature and pressure stabilization

58 Stabilization of magnetic field temperature frequency c Maxime Brodeur

59 Stabilization of magnetic field including linear drift of magnetic field

60 New temperature-stabilization system Heater Fan temperature sensor Slobodan Djekic and Melanie Marie-Jeanne

61 New temperature regulation +/- 15mK

62 +/- 0.1 mbar New pressure regulation He recovery line

63 +/- 5mK New temperature regulation - first results

64 Isomerism in 68 Cu: as produced by ISOLDE isolation of the 1 + ground state isolation of the 6 - isomeric state Resolving power of excitation: R ≈ 10 7  Population inversion of nuclear states  Preparation of an isomerically pure beam J. Van Roosbroeck et al., Phys. Rev. Lett. 92, 112501 (2004) K. Blaum et al., Europhys. Lett. 67, 586 (2004) Isomer Separation: 68 Cu

65 Isomerically pure ion beam Tape station Beta-counter Trap assisted spectroscopy

66 Decay in the buffer-gas-filled preparation trap ZXZX A Z-1 Y A e+e+ + produced at ISOLDE not produced at ISOLDE 20 cm z (mm) 4 He e+e+ e+e+ ZXZX A ZXZX A e+e+ ZXZX A Z-1 Y A A A ZXZX A e+e+ ZXZX A e+e+  Make more radioactive species available  Nearly simultaneous  c measurement of mother and daughter nuclei  Test candidate: 37 K  37 Ar  Make more radioactive species available  Nearly simultaneous  c measurement of mother and daughter nuclei  Test candidate: 37 K  37 Ar A novel idea: In-trap decay mass spectrometry Herlert et al., New J. Phys. 7, 44 (2005)

67 In-trap decay results mass spetrometry of daughter nuclide 37 K + 37 Ar + Elements/isotopes which are in principle not produced are accessible!

68 Result for doubly charged (stable) xenon ions Herlert et al., IJMS 251, 131 (2006)

69 mass determination with a time-of-flight cyclotron resonance detection technique limited by: nuclide production rate above 100 s -1 half-life (so far) over 65ms systematic uncertainty limit: Summary so far mass measurements on more than 300 radionuclides at ISOLTRAP for tests of nuclear structure, mass models, a contributions to a CKM unitarity test,... new techniques and development: in-trap decay method, new ion sources and detector, magnetic field stabilization, new excitation schemes,... (  m/m) lim  8  10 -9

70 Thanks to my co-workers: G. Audi, S. Baruah, D. Beck, K. Blaum, G. Bollen, M. Breitenfeldt, P. Delahaye, M. Dworschak, S. George, C. Guénaut, U. Hager, F. Herfurth, A. Kellerbauer, H.-J. Kluge, D. Lunney, M. Marie-Jeanne, M. Mukherjee, S. Schwarz, R. Savreux, L. Schweikhard, C. Weber, C. Yazidjian,..., and the ISOLTRAP and ISOLDE collaboration Thanks for the funding and support: BMBF, GSI, CERN, ISOLDE, EU networks EUROTRAPS, EXOTRAPS, and NIPNET Thanks a lot for your attention! Not to forget …


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