Teresa Kurtukian-Nieto Centre d’Etudes Nucléaires de Bordeaux Gradignan Precision half-life determination of the superallowed 0 + → 0 + β + -emmiters 42 Ti, 38 Ca, 30 S and the mirror β transitions of 39 Ca, 31 S and 29 P Workshop of ESNT: Isospin symmetry and its breaking in nuclear structure CEA/SPhN-Saclay, April 29th 2011
Teresa Kurtukian Nieto, CENBG April 29th CEA/SPhN Workshop of the ESNT Experimental ft measurements T 1/2 Q EC BR Precision measurements required: Q EC → mass measurements: f ~ Q 5 T 1/2, BR → -decay studies: t = T1/2 / BR to test Ft value required relative precision ~10 -3 Mirror Transitions T=1/2 Super Allowed Fermi 0+ → 0+
Teresa Kurtukian Nieto, CENBG April 29th CEA/SPhN Workshop of the ESNT typical setup: - beam purification system: traps - beta detector - gamma detectors Half-life measurements: Experimental details JYFL – IGISOL ISOLDE / CERN JYFL – IGISOL ISOLDE / CERN
Teresa Kurtukian Nieto, CENBG April 29th CEA/SPhN Workshop of the ESNT JYFLTRAP detector Ge detectors Tape transport system Typical setup: JYFL – IGISOL
Teresa Kurtukian Nieto, CENBG April 29th CEA/SPhN Workshop of the ESNT detection setup - plastic scintillator - germanium tape transport system Typical setup: JYFL – IGISOL
Teresa Kurtukian Nieto, CENBG April 29th CEA/SPhN Workshop of the ESNT Typical setup: ISOLDE / CERN radioactive ions detection - gas counter - germanium GSI tape system
Teresa Kurtukian Nieto, CENBG April 29th CEA/SPhN Workshop of the ESNT Half-life measurements: Experimental details measurement principle cycles - isotope accumulation - purification - transport -decay measurement -remaining activity evacuation measurement principle cycles - isotope accumulation - purification - transport -decay measurement -remaining activity evacuation different fixed dead times: 2 s, 8 s, 100 s different detector high-voltages different detection thresholds
Teresa Kurtukian Nieto, CENBG April 29th CEA/SPhN Workshop of the ESNT Data analysis: cycle selection: no beam, detector sparking… half-life cuts: test of dead time correction half-life as a function of background, of rate, of detector settings Is there any dependence of the half-life of these parameters? error budget Half-life measurements: Experimental details
Super Allowed Fermi 0+ → 0+
Teresa Kurtukian Nieto, CENBG April 29th CEA/SPhN Workshop of the ESNT all nuclei of interest Experimental quantities: Q values: traps, high precision “easily” reachable half-lives: feasible branching ratios: hard part… Error budget
Super Allowed Fermi 0+ → 0+: 42 Ti
Teresa Kurtukian Nieto, CENBG April 29th CEA/SPhN Workshop of the ESNT Beam purification: JYFLTRAP
Teresa Kurtukian Nieto, CENBG April 29th CEA/SPhN Workshop of the ESNT Typical spectrum: one run
Teresa Kurtukian Nieto, CENBG April 29th CEA/SPhN Workshop of the ESNT Implantation on the tape?
Teresa Kurtukian Nieto, CENBG April 29th CEA/SPhN Workshop of the ESNT 2s2s 8s8s 100 s Dead time correction: part 1
Teresa Kurtukian Nieto, CENBG April 29th CEA/SPhN Workshop of the ESNT test of dead time correction Dead time correction: part 2
Teresa Kurtukian Nieto, CENBG April 29th CEA/SPhN Workshop of the ESNT Different experimental conditions: thresholds and high-voltages
Teresa Kurtukian Nieto, CENBG April 29th CEA/SPhN Workshop of the ESNT counting statistics:0.45 dead time correction:0.01 experimental parameters (threshold, HV):0.00 T 1/2 as function of background:0.00 T 1/2 as function of counting rate:0.00 “wrong” implantation: Total:0.45 T 1/2 ( 42 Ti) = ± 0.45 ms Error budget
Teresa Kurtukian Nieto, CENBG April 29th CEA/SPhN Workshop of the ESNT T. Kurtukian Nieto et al., PRC80 (2009) BR = 48.2(15)% 611 keV Ft = 3114(79) Half-life of 42 Ti: JYFL TiT 1/2 = ± 0.45 ms (2.16 ‰)
Teresa Kurtukian Nieto, CENBG April 29th CEA/SPhN Workshop of the ESNT Half-life of 42 Ti:
Super Allowed Fermi 0+ → 0+: 38 Ca
Teresa Kurtukian Nieto, CENBG April 29th CEA/SPhN Workshop of the ESNT Half-life of 38 Ca: ISOLDE CaT 1/2 = ± 1.9 ms Blank et al., EPJ A 44,363 (2010)
Teresa Kurtukian Nieto, CENBG April 29th CEA/SPhN Workshop of the ESNT Half-life of 38 Ca:
Super Allowed Fermi 0+ → 0+: 30 S
Teresa Kurtukian Nieto, CENBG April 29th CEA/SPhN Workshop of the ESNT Half-life measurements : 30 S JYFL 2009
Teresa Kurtukian Nieto, CENBG April 29th CEA/SPhN Workshop of the ESNT Half-life measurements : 30 S 30 ST 1/2 = ± 1.7 ms (1.45 ‰) Souin, et al., EPJA (2011) 30 P(T 1/2 = ± 0.24 s) as contamination as daughter need to characterize both contributions - filiation of 30 S no additional parameter - production (mass separator) background constraint required example run
Teresa Kurtukian Nieto, CENBG April 29th CEA/SPhN Workshop of the ESNT Half-life measurements : 30 S
Teresa Kurtukian Nieto, CENBG April 29th CEA/SPhN Workshop of the ESNT Error budget sensitive improvement for half-lives some difficult work to do for branching ratios
Mirror decay
Teresa Kurtukian Nieto, CENBG April 29th CEA/SPhN Workshop of the ESNT Mirror decay Measurements required: -decay Q value super-allowed branching ratio -decay half-life - angular correlation coefficient N. Severijns, O. Naviliat-Cuncic
Teresa Kurtukian Nieto, CENBG April 29th CEA/SPhN Workshop of the ESNT Status in 2009 Experimental quantities: half-lives: feasible
Teresa Kurtukian Nieto, CENBG April 29th CEA/SPhN Workshop of the ESNT Mirror transitions: Half-lives of 39 Ca Blank et al., EPJ A 44,363 (2010)
Teresa Kurtukian Nieto, CENBG April 29th CEA/SPhN Workshop of the ESNT T. Kurtukian Nieto, A. Bacquias et al. T 1/2 = (18) ms Mirror transitions: Half-life of 31 S: JYFL 2009
Teresa Kurtukian Nieto, CENBG April 29th CEA/SPhN Workshop of the ESNT JYFL 2009 Mirror transitions: Half-life of 29 P: preliminary T. Kurtukian Nieto, A. Bacquias et al.
Teresa Kurtukian Nieto, CENBG April 29th CEA/SPhN Workshop of the ESNT Error budget
Branching Ratio Measurements
Need to know the efficiency with a precision of 0.1% calibration programme of a monocristal detector: - source measurements - MC simulations Ge Capot Al Detector scheme J. Souin
RX of the detector Scanning done with a collimated 137 Cs (CSNSM Orsay) HPGe X-Y table 137 Cs collimated (477MBq) J. Souin
Teresa Kurtukian Nieto, CENBG April 29th CEA/SPhN Workshop of the ESNT Determination of the germanium active volumen Front cap Length of the hole (13.6mm larger than expected) J. Souin Scanning done with collimated 137Cs source
Teresa Kurtukian Nieto, CENBG April 29th CEA/SPhN Workshop of the ESNT Calibration programme at Bordeaux Gamma sources (with BR know with high precition) done at ISOLDE: 75Se, 27Mg, 24Na, 66Ga, 56Co 133 Ba, 60 Co, 207 Bi, 137 Ce, 152 Eu, 88 Y, 85 Sr, 51 Cr, 54 Mn, 57 Co
Teresa Kurtukian Nieto, CENBG April 29th CEA/SPhN Workshop of the ESNT Summary : 0+->
Teresa Kurtukian Nieto, CENBG April 29th CEA/SPhN Workshop of the ESNT Summary Mirror Transitions
Teresa Kurtukian Nieto, CENBG April 29th CEA/SPhN Workshop of the ESNT The End