Half-life measurements using SCEPTAR at ISAC-I

Transcription

1 Half-life measurements using SCEPTAR at ISAC-I S. Triambak May 20, 2008

2 The 8π Array at TRIUMF 1/2 + Al + mylar tape 19 Ne 0.004% 3/ Plastic scintillator 19 Ne beam 0.01% 5/2 + 1/ % 1/ F Pb shielding Compton suppressed Ge detector 8π array: HPGe + SCEPTAR (plastic) + DANTE (BaF 2 ) + PACES (Si) Previous half-life measurements at ISAC GPS (β counting using gas counter): 26 Na, 62 Ga, 26 Al m Gamma-ray method: 26 Na, 18 Ne New program for precision half-life measurements in TRIUMF when GPS or γ-rays can not be used.

3 Beyond the minimal Standard Model Scalar and tensor interactions (from allowed beta-decays) Right-handed interactions SU(2) L SU(2) R U(1) Jackson, Treiman and Wyld (1957) d 4 Γ de edω edω ν Measured A β values: A β = ± a p 1+a e p ν m βν E ee ν +b e F E e + J [ J p A e p β E e + B ν ν E ν = ± b = ± c For the case of 19 Ne: + D ] pe pν E ee ν Define mixing ratio λ = C AM GT C V M F [ ] Ft R = = 1 [ 1 + λ 2 (1 + ] y2 ) 2 (1 + x 2 ) Ft 19 Ne x δ ζ; y δ + ζ. a F.P. Calaprice, S.J. Freedman et al., Phys. Rev. Lett. 35, 1566 (1975). b D.F. Schreiber, Ph.D. thesis, Princeton University (1983). c G.L. Jones, Ph.D. thesis, Princeton University (1996).

4 Beyond the minimal Standard Model Scalar and tensor interactions (from allowed beta-decays) Right-handed interactions SU(2) L SU(2) R U(1) Jackson, Treiman and Wyld (1957) d 4 Γ de edω edω ν Measured A β values: A β = ± a p 1+a e p ν m βν E ee ν +b e F E e + J [ J p A e p β E e + B ν ν E ν = ± b = ± c For the case of 19 Ne: + D ] pe pν E ee ν Define mixing ratio λ = C AM GT C V M F [ ] Ft R = = 1 [ 1 + λ 2 (1 + ] y2 ) 2 (1 + x 2 ) Ft 19 Ne x δ ζ; y δ + ζ. a F.P. Calaprice, S.J. Freedman et al., Phys. Rev. Lett. 35, 1566 (1975). b D.F. Schreiber, Ph.D. thesis, Princeton University (1983). c G.L. Jones, Ph.D. thesis, Princeton University (1996).

5 Beyond the minimal Standard Model Scalar and tensor interactions (from allowed beta-decays) Right-handed interactions SU(2) L SU(2) R U(1) Jackson, Treiman and Wyld (1957) d 4 Γ de edω edω ν Measured A β values: A β = ± a p 1+a e p ν m βν E ee ν +b e F E e + J [ J p A e p β E e + B ν ν E ν = ± b = ± c For the case of 19 Ne: + D ] pe pν E ee ν Define mixing ratio λ = C AM GT C V M F [ ] Ft R = = 1 [ 1 + λ 2 (1 + ] y2 ) 2 (1 + x 2 ) Ft 19 Ne x δ ζ; y δ + ζ. a F.P. Calaprice, S.J. Freedman et al., Phys. Rev. Lett. 35, 1566 (1975). b D.F. Schreiber, Ph.D. thesis, Princeton University (1983). c G.L. Jones, Ph.D. thesis, Princeton University (1996).

6 Beyond the minimal Standard Model Scalar and tensor interactions (from allowed beta-decays) Right-handed interactions SU(2) L SU(2) R U(1) Jackson, Treiman and Wyld (1957) d 4 Γ de edω edω ν Measured A β values: A β = ± a p 1+a e p ν m βν E ee ν +b e F E e + J [ J p A e p β E e + B ν ν E ν = ± b = ± c For the case of 19 Ne: + D ] pe pν E ee ν Define mixing ratio λ = C AM GT C V M F [ ] Ft R = = 1 [ 1 + λ 2 (1 + ] y2 ) 2 (1 + x 2 ) Ft 19 Ne x δ ζ; y δ + ζ. a F.P. Calaprice, S.J. Freedman et al., Phys. Rev. Lett. 35, 1566 (1975). b D.F. Schreiber, Ph.D. thesis, Princeton University (1983). c G.L. Jones, Ph.D. thesis, Princeton University (1996).

7 Beyond the minimal Standard Model Scalar and tensor interactions (from allowed beta-decays) Right-handed interactions SU(2) L SU(2) R U(1) Jackson, Treiman and Wyld (1957) d 4 Γ de edω edω ν Measured A β values: A β = ± a p 1+a e p ν m βν E ee ν +b e F E e + J [ J p A e p β E e + B ν ν E ν = ± b = ± c For the case of 19 Ne: + D ] pe pν E ee ν Define mixing ratio λ = C AM GT C V M F [ ] Ft R = = 1 [ 1 + λ 2 (1 + ] y2 ) 2 (1 + x 2 ) Ft 19 Ne x δ ζ; y δ + ζ. a F.P. Calaprice, S.J. Freedman et al., Phys. Rev. Lett. 35, 1566 (1975). b D.F. Schreiber, Ph.D. thesis, Princeton University (1983). c G.L. Jones, Ph.D. thesis, Princeton University (1996).

8 The case of 19 Ne Ft( 19 Ne) = ± 3.2 s d t 1/2 known to 0.2%, we aim to measure it to 0.01%. Fractional uncertainties of each contribution: d N. Severijns, M. Tandecki et al., Phys. Rev. C. 78, (2008)

9 The case of 19 Ne Ft( 19 Ne) = ± 3.2 s d t 1/2 known to 0.2%, we aim to measure it to 0.01%. Exclusion plots for right-handed currents: superallowed decays neutron TWIST 19 Ne (1975) All nuclear long pol 19 Ne (1996) d N. Severijns, M. Tandecki et al., Phys. Rev. C. 78, (2008)

10 The case of 19 Ne Ft( 19 Ne) = ± 3.2 s d t 1/2 known to 0.2%, we aim to measure it to 0.01%. Exclusion plots for right-handed currents: superallowed decays neutron TWIST 19 Ne (1975) All nuclear long pol 19 Ne (1996) d N. Severijns, M. Tandecki et al., Phys. Rev. C. 78, (2008)

11 The case of 19 Ne Ft( 19 Ne) = ± 3.2 s d t 1/2 known to 0.2%, we aim to measure it to 0.01%. Exclusion plots for right-handed currents: superallowed decays neutron TWIST 19 Ne (1975) All nuclear long pol 19 Ne (1996) d N. Severijns, M. Tandecki et al., Phys. Rev. C. 78, (2008)

12 The case of 19 Ne Ft( 19 Ne) = ± 3.2 s d t 1/2 known to 0.2%, we aim to measure it to 0.01%. Exclusion plots for right-handed currents: superallowed decays neutron TWIST 19 Ne (1975) All nuclear long pol 19 Ne (1996) d N. Severijns, M. Tandecki et al., Phys. Rev. C. 78, (2008)

13 The case of 19 Ne Limits on scalar currents: Ft [s] Z of daughter For purely Fermi and GT decays, a F = 1 and a GT = 1/3 For purely V A, b F b F me E e = 0 Ft Ft 0 [1 b F ]

14 The case of 19 Ne Limits on scalar currents: Ft [s] Z of daughter For purely Fermi and GT decays, a F = 1 and a GT = 1/3 For purely V A, b F b F me E e = 0 Ft Ft 0 [1 b F ]

15 The case of 19 Ne Limits on scalar currents: 3090 C S /C V = (14) Ft [s] Z of daughter For purely Fermi and GT decays, a F = 1 and a GT = 1/3 For purely V A, b F b F me E e = 0 Ft Ft 0 [1 b F ]

16 The case of 19 Ne Limits on scalar currents: Using Calaprice (1975) Ft [s] Z of daughter For purely Fermi and GT decays, a F = 1 and a GT = 1/3 For purely V A, b F b F me E e = 0 Ft Ft 0 [1 b F ]

17 The case of 19 Ne Limits on scalar currents: 3090 Using Jones (1996) + 2σ change in Ft Ft [s] Z of daughter For purely Fermi and GT decays, a F = 1 and a GT = 1/3 For purely V A, b F b F me E e = 0 Ft Ft 0 [1 b F ]

18 The case of 19 Ne Limits on scalar currents: 3090 Improved precision in Ft Ft [s] Z of daughter For purely Fermi and GT decays, a F = 1 and a GT = 1/3 For purely V A, b F b F me E e = 0 Ft Ft 0 [1 b F ]

19 Preliminary tests using 26 Na Taken data in both MCS mode and the regular mode at 8π-4 shifts (April 29 - May 01) Dead-time corrections, taken in the range from 5 30µs Counts Time (0.1 s/ch)

20 Preliminary tests using 26 Na An example with 5µs deadtime case Counts Time (0.1 s/ch)

21 Preliminary results using 26 Na T 1/2 (seconds) CFD low CFD medium Gain low Runs

22 Preliminary results using 26 Na T 1/2 (seconds) CFD low CFD medium Gain low Runs Continue testing systematics (especially rate-dependence)