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 Teresa Kurtukian-Nieto Workshop of ESNT: Isospin symmetry and its breaking in nuclear structure CEA/SPhN-Saclay, April 29th 2011

Experimental ft measurements

BR 0 + T 1/2 Q EC

Precision measurements required:



Q EC →

mass measurements:

f ~ Q 5



T 1/2 , BR →

b

-decay studies:

t = T1/2 / BR 0 +

to test

Ft

value  required

relative precision ~10 -3 Super Allowed Fermi 0+ → 0+ F

t



k g v

2

M F

2 1  1  

R



Mirror Transitions T=1/2 F

t



k g v

2

M F

2  1  

R

  1 1  

f a

/

f v

  2 

CEA/SPhN Workshop of the ESNT April 29th 2011 2 Teresa Kurtukian Nieto, CENBG

•

typical setup:

Half-life measurements:

Experimental details 

JYFL – IGISOL



ISOLDE / CERN - beam purification system: traps - beta detector - gamma detectors Teresa Kurtukian Nieto, CENBG CEA/SPhN Workshop of the ESNT April 29th 2011 3

b

detector Ge detectors Tape transport system Teresa Kurtukian Nieto, CENBG

Typical setup:

JYFL – IGISOL JYFLTRAP CEA/SPhN Workshop of the ESNT April 29th 2011 4

Typical setup:

JYFL – IGISOL

-

detection setup

b plastic scintillator g germanium

tape transport system Teresa Kurtukian Nieto, CENBG CEA/SPhN Workshop of the ESNT April 29th 2011 5

Typical setup:

ISOLDE / CERN radioactive ions detection

b

gas counter

g

germanium Teresa Kurtukian Nieto, CENBG GSI tape system CEA/SPhN Workshop of the ESNT April 29th 2011 6

Half-life measurements:

Experimental details

measurement principle cycles

- isotope

accumulation

-

purification

-

transport decay

measurement - remaining activity

evacuation

• • •

different fixed dead times: 2

m

s, 8

m

s, 100

m

s different detector high-voltages different detection thresholds Teresa Kurtukian Nieto, CENBG CEA/SPhN Workshop of the ESNT April 29th 2011 7

Half-life measurements:

Experimental details •

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 Teresa Kurtukian Nieto, CENBG CEA/SPhN Workshop of the ESNT April 29th 2011 8

Super Allowed Fermi 0+

→

0+

Error budget

all nuclei of interest

• • •

Experimental quantities: Q values: traps, high precision “easily” reachable half-lives: feasible branching ratios: hard part… Teresa Kurtukian Nieto, CENBG CEA/SPhN Workshop of the ESNT April 29th 2011 10

Super Allowed Fermi 0+

→

0+:

42 Ti

Beam purification: JYFLTRAP

Teresa Kurtukian Nieto, CENBG CEA/SPhN Workshop of the ESNT April 29th 2011 12

Typical spectrum: one run

Teresa Kurtukian Nieto, CENBG CEA/SPhN Workshop of the ESNT April 29th 2011 13

Implantation on the tape?

Teresa Kurtukian Nieto, CENBG CEA/SPhN Workshop of the ESNT April 29th 2011 14

2

m

s 8

m

s 100

m

s Teresa Kurtukian Nieto, CENBG

Dead time correction: part 1

CEA/SPhN Workshop of the ESNT April 29th 2011 15

Dead time correction: part 2



test of dead time correction Teresa Kurtukian Nieto, CENBG CEA/SPhN Workshop of the ESNT April 29th 2011 16

Different experimental conditions: thresholds and high-voltages

Teresa Kurtukian Nieto, CENBG CEA/SPhN Workshop of the ESNT April 29th 2011 17

Error budget

• • • • • •

counting statistics: dead time correction: experimental parameters (threshold, HV): T 1/2 as function of background: T 1/2 as function of counting rate: “wrong” implantation: 0.45

0.01

0.00

0.00

0.00

0.00

------------------------------------------------------------------- Total: 0.45

 

T 1/2 ( 42 Ti) = 208.14

±

0.45 ms Teresa Kurtukian Nieto, CENBG CEA/SPhN Workshop of the ESNT April 29th 2011 18

Half-life of 42 Ti: JYFL 2008

42 Ti

T 1/2 = 208.14 ± 0.45

ms

(2.16 ‰)

611 keV T. Kurtukian Nieto et al., PRC80 (2009) 035502 BR = 48.2(15)% Ft = 3114(79) CEA/SPhN Workshop of the ESNT Teresa Kurtukian Nieto, CENBG April 29th 2011 19

Half-life of 42 Ti: Teresa Kurtukian Nieto, CENBG CEA/SPhN Workshop of the ESNT April 29th 2011 20

Super Allowed Fermi 0+

→

0+:

38 Ca

Half-life of 38 Ca: ISOLDE 2007

38

Ca T 1/2 = 443.8

±

1.9 ms

Blank et al., EPJ A 44,363 (2010)

Teresa Kurtukian Nieto, CENBG CEA/SPhN Workshop of the ESNT April 29th 2011 22

Half-life of 38 Ca: Teresa Kurtukian Nieto, CENBG CEA/SPhN Workshop of the ESNT April 29th 2011 23

Super Allowed Fermi 0+

→

0+:

30 S

Half-life measurements : 30 S JYFL 2009 Teresa Kurtukian Nieto, CENBG CEA/SPhN Workshop of the ESNT April 29th 2011 25

Teresa Kurtukian Nieto, CENBG Half-life measurements : 30 S 30 P

  (T 1/2 = 148.88 as contamination as daughter ± 0.24

s

) need to characterize both contributions -

filiation of 30 S

no additional parameter -

production

(mass separator) background constraint required

30 S

T 1/2 = 1175.9

±

1.7 ms (1.45 ‰)

Souin, et al., EPJA (2011)

CEA/SPhN Workshop of the ESNT April 29th 2011 26

Half-life measurements : 30 S Teresa Kurtukian Nieto, CENBG CEA/SPhN Workshop of the ESNT April 29th 2011 27

Error budget

2007 2011

Teresa Kurtukian Nieto, CENBG sensitive improvement for half-lives some difficult work to do for branching ratios CEA/SPhN Workshop of the ESNT April 29th 2011 28

Mirror

b

decay

Mirror

b

decay

Teresa Kurtukian Nieto, CENBG

• • • •

Measurements required:

b

-decay Q value super-allowed branching ratio

b

-decay half-life

b

-

n

angular correlation coefficient N. Severijns, O. Naviliat-Cuncic CEA/SPhN Workshop of the ESNT April 29th 2011 30

Status in 2009

Experimental quantities:

•

half-lives: feasible Teresa Kurtukian Nieto, CENBG CEA/SPhN Workshop of the ESNT April 29th 2011 31

Mirror transitions: Half-lives of 39 Ca

Blank

et al.

, EPJ A 44,363 (2010)

Teresa Kurtukian Nieto, CENBG CEA/SPhN Workshop of the ESNT April 29th 2011 32

Mirror transitions: Half-life of 31 S: JYFL 2009 Teresa Kurtukian Nieto, CENBG T. Kurtukian Nieto, A. Bacquias et al.

T 1/2 = 2546.4(18) ms CEA/SPhN Workshop of the ESNT April 29th 2011 33

Mirror transitions: Half-life of 29 P: JYFL 2009 T. Kurtukian Nieto, A. Bacquias et al.

Teresa Kurtukian Nieto, CENBG CEA/SPhN Workshop of the ESNT April 29th 2011 34

Error budget

2009 2011

Teresa Kurtukian Nieto, CENBG CEA/SPhN Workshop of the ESNT April 29th 2011 35

Branching Ratio Measurements

•

Need to know the efficiency with a precision of 0.1%

•

calibration programme of a monocristal detector: - source measurements - MC simulations Detector scheme

Ge Capot Al

J. Souin

X-Y table RX of the detector Scanning done with a collimated 137 Cs (CSNSM Orsay) HPGe 137 Cs collimated (477MBq) J. Souin

Scanning done with collimated 137Cs source Determination of the germanium active volumen

Length of the hole (13.6mm larger than expected)

J. Souin Teresa Kurtukian Nieto, CENBG Front cap CEA/SPhN Workshop of the ESNT April 29th 2011 39

Teresa Kurtukian Nieto, CENBG 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 CEA/SPhN Workshop of the ESNT April 29th 2011 40

Summary : 0+->0+

2007 2011

Teresa Kurtukian Nieto, CENBG CEA/SPhN Workshop of the ESNT April 29th 2011 41

Summary Mirror Transitions

2009 2011

Teresa Kurtukian Nieto, CENBG CEA/SPhN Workshop of the ESNT April 29th 2011 42

The End

Teresa Kurtukian Nieto, CENBG CEA/SPhN Workshop of the ESNT April 29th 2011 43