PDF TITAN Mass Measurement of 11 Li

TITAN Mass Measurement of ¹¹ Li

(and other halo nuclei)

Ryan Ringle, TRIUMF

The weather in Vancouver

(according to the tourist board)

The weather in Vancouver

(the other 364 days of the year)

Outline

ISAC @ TRIUMF

The TITAN experiment

Penning trap mass spectrometry Towards shorter half lives

Results of

Li measurement

Results of other halo nuclei mass measurements

ISAC:

Highest power for On-Line facilities, we go up to 100µA

@ 500MeV DC proton

ISAC has 3 exper. areas:

• Low energy (60keV)

• ISAC I (cont. up 1.8 MeV/u)

• ISAC II (up to 10 MeV/

u, present license to 5 MeV/U)

Many experimental stations:

• TRINAT, Beta-NMR, 8pi, tape-station, TITAN, Co-linear laser spec, polarized beam line, etc

• DRAGON, TUDA, TACTIC, GPS (Leuven)

• TIGRESS, EMMA (2010), GPS (Maya)

ISAC at TRIUMF

Yields:

11Li - 4x10⁴/s

74Rb - 2x10⁴/s

62Ga - 2x10³/s

The TITAN Experiment

ISAC Beam

RFQ

Cooling and Bunching

Penning Trap

Mass Measurement

EBIT

Charge State Breeding

!talk by T. Brunner"

!E ~ 20#60 keV"

Penning Trap Mass Spectrometry

3D ion confinement:

linear magnetic field +quadrupolar electric field

Resulting ion motion:

3 independent eigenmotions

!+,!-,!z

ω

= ω

+ ω

= q m B ω

< ω

< ω

True cyclotron frequency is the sum of radial eigenmotions

Application of quadrupolar RF field causes beating between reduced cyclotron and magnetron motions

Extraction through magnetic field converts radial energy to

longitudinal energy

Measure TOF to determine the center frequency

+

R ! "c.Trf

Towards Shorter Half Lives

Measurement time scales:

initial magnetron preparation dipolar RF excitation ~ 10 ms Lorentz steerer FREE

cyclotron motion excitation (limited by half life)

R ! "c!Trf = (q/m)!B!Trf

charge breeding (increase q)

buy a bigger magnet (increase B)

different RF excitation scheme (reduce FWHM)

Ramsey excitation - S. George et al., PRL 98, 162501 (2007) Octupolar excitation - R. Ringle et al., IJMS 262, 33 (2007) S. Eliseev et al., IJMS 262, 45 (2007)

+ .

E! B!

. . .

. .

F ! = q( E ! + ! v × B ! )

net offset in ExB direction Principle: generate electric dipole

field in strong magnetic field region to move ions off axis

R. Ringle et al., IJMS 263, 38 (2007)

Penning trap benchmarks

6,7

Li mass comparison

Compare to SMILETRAP* values

*14# deviation of m(⁷Li) from AME03

*Sz. Nagy et al., PRL 96, 163004 (2006) Agreement is observed on the 2(7)x10^-9 level

12C vs. ⁶Li

mass shift insignificant on the 3(4)x10^-8 level over six mass units

Mass dependent frequency shifts

MTITAN-MSMILE = 13(39) eV

7Li $m/m ~ 5x10^-10

Halo Nuclei

one-proton halo two-proton halo binary system

one-neutron halo two-neutron halo

four-neutron halo

measured with TITAN proposed

S 2n of All Bound Nuclei

11Li ⁶He

17B

14Be

27F

8He

slide from D. Lunney

Li Isotope Shifts

R. Sánchez et al., PRL 96, 033002 (2006)

altered charge radius, r

, of

Li could indicate a perturbed

Li core

Isotopic Shift

mass shift term (MS)

~ 10 GHz for Li

δν

− δν

= F δ < r

>

field shift term

~ 0.001 GHz for Li

- mass shift terms calculated by Z.-C. Yan and G.W.F. Drake

Z.-C Yan and G.W.F. Drake, PRL 91, 113004 (2003)

- ¹¹Li mass measurement with $m " 1 keV/c² required to remove it as a source of significant uncertainty

- ^6,7Li rc determined via elastic electron scattering

- optical isotope shift measurements provide relative shift

C.W. de Jager et al., At. Data Nucl. Data Tables 14, 479 (1974)

11 Li S 2n Value

Thibault et al.Wouters et al.

Kobayashi et al.

Young et al.

Bachelet et al.

150 200 250 300 350 400

S 2n [keV]

AME '03

Five previous measurements of S

(

Li)

Reference Method S2n [keV]

Thibault et al. Mass Spec. 170 ± 80 J.M. Wouters et al. TOF 320 ± 120 T. Kobayashi et al. ¹¹B(#^-,#⁺)¹¹Li 340 ± 50

B.M. Young et al. ¹⁴C(¹¹B,¹¹Li)¹⁴O 295 ± 35 Bachelet et al. Mass Spec. 376 ± 5

AME ’03: S2n(¹¹Li) = 300 ± 20 keV

- Need a precision of $m " 5 keV/c² to confirm accuracy of Bachelet et al.

- An S2n(¹¹Li) value with 1% uncertainty, $m " 3 keV/c², would provide a solid test for nuclear theory.

PRC 12, 644 (1975)

Z. Phys. A 331, 229 (1988) KEK Rep. 91-22 (1991) PRL 71, 4124 (1993)

Eur. Phys. J. A 25, 31 (2005)

G. Audi et al., Nucl. Phys. A 729, 129 (2003)

- Need a precision of $m " 1 keV/c² for charge radius calculations.

TITAN Mass Measurement of ^9,11 Li

(preliminary)

-100 -50 0 50 100

!_RF - 5147353.46 [Hz]

35 40 45 50 55 60

TOF ["s]

11Li⁺

#m/m ~ 7x10^-8

T_1/2 = 8.5 ms

-5 0 5

!_RF - 6,297,542 [Hz]

37 39 41 43 45 47 49 51

TOF ["s]

9Li⁺

#m/m ~ 8x10^-9 T_1/2 = 177 ms

Measurement

-2 -1 0 1 2

M.E. TITAN - M.E. AME03 [keV]

AME03

TITAN

9Li

Measurement

-80 -60 -40 -20 0 20

M.E. TITAN-M.E. AME03 [keV]

AME03

TITAN

11Li

6 measurements

$m/m ~ 3x10^-9

9 measurements

$m/m ~ 3x10^-8

$m ~ 50 eV

$m ~ 550 eV

TITAN Mass Measurement of ^9,11 Li

(preliminary)

-100 -50 0 50 100

!_RF - 5147353.46 [Hz]

35 40 45 50 55 60

TOF ["s]

11Li⁺

#m/m ~ 7x10^-8

T_1/2 = 8.5 ms

-5 0 5

!_RF - 6,297,542 [Hz]

37 39 41 43 45 47 49 51

TOF ["s]

9Li⁺

#m/m ~ 8x10^-9 T_1/2 = 177 ms

Thibault et al.Wouters et al.

Kobayashi et al.

Young et al.

Bachelet et al.

150 200 250 300 350 400

S 2n [keV]

AME '03

TITAN Mass Measurement of ^9,11 Li

(preliminary)

-100 -50 0 50 100

!_RF - 5147353.46 [Hz]

35 40 45 50 55 60

TOF ["s]

11Li⁺

#m/m ~ 7x10^-8

T_1/2 = 8.5 ms

-5 0 5

!_RF - 6,297,542 [Hz]

37 39 41 43 45 47 49 51

TOF ["s]

9Li⁺

#m/m ~ 8x10^-9 T_1/2 = 177 ms

Thibault et al.Wouters et al.

Kobayashi et al.

Young et al.

Bachelet et al.

TITAN '07

150 200 250 300 350 400

S 2n [keV]

AME '03

(%S2n)AME03 ~ 3.5#

(%S2n)Bachelet ~ 1.4#

How Big is ⁸ He?

P. Mueller et al., PRL 99, 252501 (2007)

How Big is ⁸ He?

P. Mueller et al., PRL 99, 252501 (2007)

How Big is ⁸ He?

P. Mueller et al., PRL 99, 252501 (2007)

TITAN Mass Measurement of ⁸ He

(preliminary)

-20 -15 -10 -5 0 5 10 15 20

!_rf - 7075868 [Hz]

25 30 35 40 45 50 55 60

TOF ["s]

8He⁺

#m/m ~ 4x10^-8

Measurements

-10 -5 0 5 10 15

M.E. TITAN-M.E. AME03 [keV]

AME03 TITAN

8He

- First direct mass measurement of ⁸He - H2 used as buffer gas in RFQ

- $m ~ 300 eV

- Produced with “broken” FEBIAD ion source

- %m ~ 1.9#

T1/2 = 117 ms

TITAN Mass Measurement of ¹¹ Be

(preliminary)

-5 0 5

!_RF - 5,157,659 [Hz]

42 47 52 57

TOF ["s]

11Be⁺

#m/m ~ 1x10^-8

Measurement

-8 -4 0 4 8

M.E. TITAN - AME03 [keV]

AME03

11Be

TITAN Measurements

-15 -10 -5 0 5 10 15

M.E. - AME04 [keV]

AME03

9Be(t,p)¹¹Be

10Be(d,p)¹¹Be

MISTRAL

TITAN

$m/m ~ 7x10^-9 (reduced by a factor of ~ 50)

T1/2 = 11 s

The TITAN mass spectrometer has been commissioned and is capable of making high-precision mass measurements of very short lived nuclei

TITAN has performed precision mass measurements of He, Li and Be halo nuclei (final analysis pending).

New halo mass measurements allow a refined charge radius determination and shed new light on the structure of halo nuclei

More mass measurements to come this year (halo, CKM, structure, HCI, etc.)

Neutrinoless &&-decay measurements using EBIT (T. Brunner on Friday)

Conclusions & Outlook

The TITANs

M. Brodeur, T. Brunner, C.

Champagne, J. Dilling, P. Delheij, S. Ettenauer, M. Good, A. Lapierre, D. Lunney, R. Ringle,

V. Ryjkov, M. Smith,

and the TITAN collaboration