PI ICR technique for high precision measurements of nuclide masses - - PowerPoint PPT Presentation

Sergey Eliseev

PI‐ICR technique for high‐precision measurements

• f nuclide masses

(development at SHIPTRAP)

• K. Blaum, M. Block, S. Chenmarev, A. Dörr, C. Droese, T. Eronen,
• P. Filjanin, M. Goncharov, M. Höcker, J. Ketter, E. Minaya Ramirez,
• D. Nesterenko, Yu. Novikov, L. Schweikhard, V. Simon

GSI Helmholtzzentrum für Schwerionenforschung GmbH, Germany Max‐Planck‐Institut für Kernphysik, Germany Institut für Physik, Ernst‐Moritz‐Arndt‐Universität,Germany Petersburg Nuclear Physics Institute, Russia

NUSTAR Meeting, March 5th

Field Examples δm/m

nuclear structure physics

shell closures, shell quenching, regions of

astrophysics

rp‐process and r‐process path, waiting‐points

weak interaction studies

CVC hypothesis, CKM matrix unitarity, Ft of

metrology, fundamental const.

α (h/mCs, mCs /mp, mp/me ), mSi

neutrino mass

0νββ, 0ν2EC

CPT tests QED in highly‐charged ions

mp and mp me- and me+ mion, electron binding energy

10‐6 ‐ 10‐7 10‐8 10‐9 ‐10‐10 <10‐11 deformation, drip lines, halos, island of stability nuclei, astrophysical reaction rates, neutron stars superallowed ß‐emitters

β-decay, EC

neutrino physics

high‐precision measurements of masses of exotic nuclides

Field Examples δm/m

nuclear structure physics

shell closures, shell quenching, regions of

astrophysics

rp‐process and r‐process path, waiting‐points

weak interaction studies

CVC hypothesis, CKM matrix unitarity, Ft of

metrology, fundamental const.

α (h/mCs, mCs /mp, mp/me ), mSi

neutrino mass

0νββ, 0ν2EC

CPT tests QED in highly‐charged ions

mp and mp me- and me+ mion, electron binding energy

10‐6 ‐ 10‐7 10‐8 10‐9 ‐10‐10 <10‐11 deformation, drip lines, halos, island of stability nuclei, astrophysical reaction rates, neutron stars superallowed ß‐emitters

β-decay, EC

neutrino physics

high‐precision measurements of masses of exotic nuclides

Penning trap the most accurate mass spectrometer

B

q/m

strong uniform static B‐field

1 q

ν νc

c =2π m

m B

B

q/m

strong uniform static B‐field

1 q

ν νc

c =2π m

m B

SHIPTRAP JYFLTRAP TRIGATRAP MLLTRAP

< 5 · 10-9 ΔB B h-1

THe‐TRAP

Max‐Planck Institute for Nuclear Physics, Heidelberg

< 10-11 ΔB B h-1

Penning trap the most accurate mass spectrometer

B

q/m uniform B‐field 1 q

ν νc

c =2π m

m B quadrupole E‐field

+ =

Penning Trap

ν ν+

+ - modified cyclotron

ν ν-

• - magnetron

ν νz

z - axial

− + +

= ν ν ν c

10 c c

10− > ν ν Δ

Penning trap the most accurate mass spectrometer

Penning‐Traps worldwide

TITAN CPT LEBIT JYFLTRAP ISOLTRAP SHIPTRAP MLLTRAP TRIGATRAP FSU

• n-line facility for short-lived nuclides

δm/m ~ 10-6 - 10-8 ultra-precise Penning trap for long-lived and stable nuclides δm/m <10-10

TITAN CPT LEBIT JYFLTRAP ISOLTRAP SHIPTRAP MLLTRAP TRIGATRAP

• n‐line facilities (short‐lived nuclides)

δm/m ~ 10‐6 ‐ 10‐8

ToF‐ICR technique

until now

PI‐ICR technique

future ?

Penning‐Traps worldwide

TITAN CPT LEBIT JYFLTRAP ISOLTRAP SHIPTRAP MLLTRAP TRIGATRAP

• n‐line facilities (short‐lived nuclides)

δm/m ~ 10‐6 ‐ 10‐8

ToF‐ICR technique

until now

PI‐ICR technique

future ?

Penning‐Traps worldwide

150‐1000 keV/u ≈ 1 eV

SHIPTRAP

gas‐filled stopping chamber RF‐quadrupole

(cooler & buncher)

superconducting magnet MCP‐detector preparation trap

reaction products From SHIP

Penning traps

measurement trap

• M. Block et al., Eur. Phys. J. D 45 (2007) 39

Currently used ToF-ICR technique

(Time-of-Flight Ion-Cyclotron-Resonance)

z B F ∂ ∂ ⋅ − =

• μ

larger μ → shorter ToF

Currently used ToF-ICR technique

(Time-of-Flight Ion-Cyclotron-Resonance)

z B F ∂ ∂ ⋅ − =

• μ

larger μ → shorter ToF

injection

Currently used ToF-ICR technique

(Time-of-Flight Ion-Cyclotron-Resonance)

z B F ∂ ∂ ⋅ − =

• μ

larger μ → shorter ToF

injection excitation of ν− μ∼r2ν−

• U0cos(ω-t)

U0cos(ω-t)

Currently used ToF-ICR technique

(Time-of-Flight Ion-Cyclotron-Resonance)

z B F ∂ ∂ ⋅ − =

• μ

larger μ → shorter ToF

injection excitation of ν− μ∼r2ν− π−pulse at νrf≈ νc

U0cos(ωrft)

• U0cos(ωrft)
• U0cos(ωrft)

U0cos(ωrft)

μ∼r2ν+

• U0cos(ω-t)

U0cos(ω-t)

Currently used ToF-ICR technique

(Time-of-Flight Ion-Cyclotron-Resonance)

z B F ∂ ∂ ⋅ − =

• μ

larger μ → shorter ToF

injection excitation of ν− μ∼r2ν− π−pulse at νrf≈ νc

U0cos(ωrft)

• U0cos(ωrft)
• U0cos(ωrft)

U0cos(ωrft)

μ∼r2ν+

• U0cos(ω-t)

U0cos(ω-t)

ejection

time of flight

νc

Nuclear Chart

Nuclear Chart

we want to

measure masses of nuclides with T1/2~100 ms with a few keV accuracy (δm/m~10-8) be able to resolve isomeric states with a few ten keV energy

Perfomance of ToF-ICR technique

singly charged ions of M=200

νc≈500 kHz N=1000

resolving power uncertainty

trapping time trapping time

r r N 6 . 1 Δ τ δν ≈

c

τ ν ν Δ ν ⋅ ⋅ =

c c c

6 . 1

r Δr=HWHM

• gain in resolving power: ~ 50
• much faster measurements
• gain in precision: ~ 5

new technique for singly‐charged ions

EC in 163Ho β

—decay of 187Re

‐ Project δQ ~ 1 eV (δQ/m < 10‐11)

determination of neutrino mass with accuracy of 0.2 eV

Analysis

neutrino-mass value (PENTATRAP)

δQ ~ 50 eV (δQ/m < 3∙10‐10)

development of experiment

163 163Ho

Ho

187 187Re

Re

Development of the ECHo‐Project (scale of experiment) Measurement of Q‐values

• f 187Re β‐decay & EC in 163Ho

with 50 eV‐uncertainty

SHIPTRAP in 2014-2015

New PI-ICR technique

(Phase-Imaging Ion-Cyclotron-Resonance)

B

− + +

= ν ν ν c

New PI-ICR technique

(Phase-Imaging Ion-Cyclotron-Resonance)

B

− + +

= ν ν ν c

− + +

= ν ν ν c

− − − −

+ = t 2 n 2 π π φ ν

+ + + +

+ = t 2 n 2 π π φ ν

position-sensitive detector

B

Penning trap

delayline delayline position position-

• sensitive

sensitive detector detector RoentDek RoentDek GmbH DLD40 GmbH DLD40

Active diameter 42 mm Channel diameter 25 μm Open area ratio >50 % Position resolution 70 μm

• Max. B-field

a few mT Time resolution ~ 10 ns

measurement of free cyclotron frequency:

− + +

= ν ν ν c

magnetron frequency ν- modified cyclotron frequency ν+

mag.reference phase (stable over days)

• mag. final phase

center (stable over days) (nuclide-independent) cyc.reference phase (stable over days)

• cyc. final phase
• +

measurement of free cyclotron frequency:

− + +

= ν ν ν c

magnetron frequency ν- modified cyclotron frequency ν+

mag.reference phase (stable over days)

• mag. final phase

center (stable over days) (nuclide-independent) cyc.reference phase (stable over days)

• cyc. final phase
• +

if production rates of exotic nuclides are extremely low and experiment time is limited?

it is desirable to skip the measurement of the reference phases

measurement of free cyclotron frequency:

− + +

= ν ν ν c

magnetron frequency ν- modified cyclotron frequency ν+

mag.reference phase (stable over days)

• mag. final phase

center (stable over days) (nuclide-independent) cyc.reference phase (stable over days)

• cyc. final phase
• +

free cyclotron frequency νc

t 2 n 2

c c

π π φ ν + =

magnetron phase cyclotron phase

c

PI-ICR vs. ToF-ICR

center magnetron phase cyclotron phase

5 6 . 1 ) ( ) ( precision in gain

c c

≅ ⋅ = =

−

π δν δν

ICR PI ICR ToF

40 05 . 1 6 . 6 . power resolving in gain ≅ ⋅ ⋅ = Δ = π π r r

!

y sensitivit higher

PI-ICR vs. ToF-ICR in experiment

δ[M(132Xe) - M(131Xe)] ~ 70 eV !!!

ToF-ICR

10-hour measurements

PI-ICR

δ[M(124Xe) - M(124Te)] ~ 300 eV

Gain in Precision ~ 4.5 !!!

PI-ICR in experiment ΔM = M(132Xe) - M(131Xe) ΔMSHIPTRAP - ΔMreference = (8 ± 35) eV δ(ΔM)SHIPTRAP = (30stat )( 12sys) eV

PI-ICR in experiment ΔM = M(132Xe) - M(131Xe)

first ever measurement of mass difference

• f singly charged medium-heavy non-mass-doublets

with a relative accuracy of 2·10-10 !!!

SHIPTRAP in 2014-2015

with an uncertainty of ~ 50 eV We are preparing for the measurement

• f the Q-value of:

β−-decay of 187Re

(1)

EC in 163Ho

(2)

Summary Summary

PI-ICR has been developed at SHIPTRAP for mass measurements on singly-charged short-lived nuclides

• PI-ICR is much faster than ToF-ICR and offers very

high mass resolving power

• Performance at SHIPTRAP:
• δ(M(132Xe) - M(131Xe)) = ± 30 eV

Plans at SHIPTRAP: Q-values of EC in 163Ho and β-decay of 187Re

Acknowledgements Acknowledgements Thank you for your attention ! Thank you for your attention !

Effects Effects that that limit limit Resolving Resolving Power and Maximum Power and Maximum Precision Precision

• f PI
• f PI-
• ICR

ICR

• Anharmonicity of the Trap Potential
• Presence of Helium in the Trap
• Instability of the Trap Potential in Time
• Instability of the B-Field in Time
• Error due to Conversion

collisions with He atoms in trap increase the size of cyclotron phase spot

Presence of Helium in the Trap Presence of Helium in the Trap

6 c c

10 5⋅ ≈ ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ ≈ ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛

+ + max max

ν Δ ν ν Δ ν

(M = 200 u ΔM=40 keV)

center magnetron cyclotron phase-accumulation time = 0.5 s r ≈ 0.5 mm

PHe ≈ 3·10-7 mbar

Anharmonicity Anharmonicity of the Trap Potential

• f the Trap Potential

...

' '

+ + + =

− − − − 4 6 2 4 harmonic

r C r C ν ν

... + + + =

6 6 6 4 4 4 2 2 2 trap

z d 2 U C z d 2 U C z d 2 U C U

...

' '

− − − =

+ + + + 4 6 2 4 harmonic

r C r C ν ν

trap center harmonic trap anharmonic trap trap center

r r t 1 t 2 Δ π π φ Δ ν Δ ≈ =

Δr-,+

Anharmonicity Anharmonicity of the Trap Potential

• f the Trap Potential

real trap magnetron phase spots t = 10 ms t = 0.5 s t = 1 s center t = 2 s

r- ≈ 1.2 mm

mHz 50 ≈

+ − max ,

ν Δ

7 c c

10 ≈ ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ ≈ ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛

+ + max max

ν Δ ν ν Δ ν

(M = 200 u ΔM=20 keV)

Instability of Trap Potential in Time Instability of Trap Potential in Time

temporal instability of trapping voltage causes angular smearing of both phase spots

10 mHz

7 c c

10 5⋅ ≈ ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ ≈ ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛

+ + max max

ν Δ ν ν Δ ν

(M = 200 u)

Instability of B Instability of B-

• Field in Time

Field in Time

temporal instability of B-field causes angular smearing of cyclotron phase spot

20 mHz

7 c c

10 2⋅ ≈ ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ ≈ ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛

+ + max max

ν Δ ν ν Δ ν

(M = 200 u)

error error in in ν

νc

c determination

determination due due to to conversion conversion

• f
• f cyclotron

cyclotron motion motion to to magnetron magnetron motion motion

center magnetron phase cyclotron phase

error error in in ν

νc

c determination

determination due due to to conversion conversion

• f
• f cyclotron

cyclotron motion motion to to magnetron magnetron motion motion

φ+

(i)

φ = constant

φ−

(f) = − φ+ (i) + φ

conversion pure cyclotron motion (before conversion) pure magnetron motion (after conversion)

Δφ−

(f) = − Δφ+ (i)

φ-

(f)

error error in in ν

νc

c determination

determination due due to to conversion conversion

• f
• f cyclotron

cyclotron motion motion to to magnetron magnetron motion motion

φ

conversion cyclotron and magnetron motions (before conversion) pure magnetron motion (after conversion)

[r−,φ-](i) [r+,φ+](i)

φ−

(f) = − φ+ (i) + φ (φ- (i) ,φ+ (i),r-/r+)

Δφ−

(f) = − Δφ+ (i) + ΔΦ

[r−,φ-](f)

error error in in ν

νc

c determination

determination due due to to conversion conversion

• f
• f cyclotron

cyclotron motion motion to to magnetron magnetron motion motion

φ = φrf

(i) - φ- (i) - φ+ (i)

ΔΦ = f (φ, ωct, S) S = r-

(i)/ r+ (i)

ΔΦmax ≈ 60·S2 [deg]

r+

(i) = 1 mm, r- (i) = 0.025 mm

0.05

• 0.05

[ ]

s t 10 10

c c −

≈ ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛

max

ν ν Δ

0.05

• 0.05

error error in in ν

νc

c determination

determination due due to to conversion conversion

• f
• f cyclotron

cyclotron motion motion to to magnetron magnetron motion motion

φ = φrf

(i) - φ- (i) - φ+ (i)

ΔΦ = f (φ, ωct, S) S = r-

(i)/ r+ (i)

ΔΦmax ≈ 60·S2 [deg]

r+

(i) = 1 mm, r- (i) = 0.025 mm

[ ]

s t 10 10

c c −

≈ ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛

max

ν ν Δ

If t = N·Tc/2

ΔΦ = 0

y x y x

magnetron motion ν- ≈ 1335 Hz; T- ≈ 750 μs

magnetron magnetron motion vs. motion vs. modified cyclotron modified cyclotron motion motion

modified cyclotron motion ν- ≈ 800000 Hz; T- ≈ 1.25 μs time of flight of 132Xe ions between the trap and the detector 1.5 μs

projection of projection of modified cyclotron modified cyclotron motion motion

modified cyclotron motion direct projection magnetron motion projection after full conversion

y x y

x

full conversion of cyclotron to magnetron motion

φ

• φ

Phase (after conversion) = - Phase (before conversion) + Const

φ (after conversion) = - φ (before conversion)

projection of trap center onto detector (nuclide-independent) reference phase (stable over days) final phase

magnetron frequency ν- modified cyclotron frequency ν+

measurement measurement sequence sequence Nr. 1

• Nr. 1

magnetron frequency ν- modified cyclotron frequency ν+

if production rates of exotic nuclides are extremely low and experiment time is limited?

magnetron frequency ν- modified cyclotron frequency ν+

measurement measurement sequence sequence Nr. 2

• Nr. 2

free cyclotron frequency νc

measurement measurement sequence sequence Nr. 2

• Nr. 2

if production rates of exotic nuclides are extremely low and experiment time is limited?

center magnetron phase cyclotron phase

t 2 n 2

c

π π φ ν + =

ANALYSIS of DE‐EXCITATION SPECTRUM

m mν

ν

163 163Ho

Ho 163

163Dy

Dyh

h +

+ ν νe

e (E

(Eν

ν)

)

163 163Dy +

Dy + E Ec

c

determination of neutrino mass with accuracy of 0.2 eV Factor of Merit = Send point Sfull spectrum = f (Q‐value)