A novel four-trap mass spectrometer for high-accuracy mass measurements on highly-charged ions

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Roberta Conley
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1 A novel four-trap mass spetrometer for high-auray mass measurements on highly-harged ions Sz. Nagy, K. Blaum, S. George, F. Herfurt, J. Ketelaer, W. Quint, S. Stahl UNI-Mainz, GSI Darmstadt Outline: Penning traps as mass spetrometers Related physis and reent results using HCI Features of the novel apparatus Present status Outlook

Penning traps as mass spetrometers = 1 2π qeb m = + + 2 2 =

10-8 10-9 Smiletrap (2002) 10-10 10-11 1979 VanDyk, Dehmelt

2 Penning traps as mass spetrometers = 1 2π qeb m = = z Si 10-5 Unertainty δm/m Smiletrap (2002) VanDyk, Dehmelt e - / e + 100ppb P.B. Shwinberg, R.S. vandyk, H.G Dehmelt, Phys. Lett 81A, year 1989 Nobel Prize in Physis: Dehmelt, Paul, Ramsey

What an be done using high auray mass spetrometry www.quantum.physik.uni-mainz.de/mats weigh QED effets diretly, (200u 0.

3 What an be done using high auray mass spetrometry weigh QED effets diretly, (200u 0.1ppb) Diret test of atomi struture alulations, measure in a Penning trap the first superheavy element determine fundamental onstants, e.g. α, m e, m p better diret test of E=m 2, if: E=h test BS-QED in strong fields, g-fator help the searh for eletron antineutrino rest mass aurate Q-values to find 02β-deay e.g. 76 Ge- 76 Se measure diretly atomi eletron binding energies (A (q-1) -A q+ -m e ) and all these (and many more) an be done using highly harged ions...

4 Why highly-harged ions -is there a benefit? / MHz U B=7 T Charge State = 1 qeb 2π m δm / m 1E-7 1E-8 1E-9 1E U δm m T ex m qbn 1/ 2 R = = m m 1 T rf = Charge State T RF =1s N=3000 In the ase of 238 U max. 92X higher resolving power an be ahieved by using q=92+ ions.

5 Reent results using HCI at SMILETRAP Sz. Nagy et al. Europhys. Lett., 74, 404, 2006 Sz. Nagy et al. Phys. Rev. Lett., 96, , 2006 Sz. Nagy et al. Eur. Phys. J. D, 39, 1, 2006

6 The layout of the ryogeni four trap-mass spetrometer B = 7 T ~10 mm 4.2 K Monitor trap 77 K 20 K ~75 mm Preparation trap2 Measurement trap Preparation trap1 4.2 K Ions from HITRAP or an EBIT

7 What s new? Features ~75 mm 238 U 92+ Referene Monitor Monitor trap Preparation trap2 Measurement trap Timing sheme: T 1 T 2 T 3 Advantages: Cryogeni temperatures -5 Highly-harged ions Non-destrutive ion detetion Diret eletron binding energy measurement No ion-ion interation Short measurement yle Continuous B-field monitoring/ alibration Preparation trap1 T = 4.2 K δb/b<10-7 /m 3, (δb/dt) (1/B)<10-10 /h Goal: δm/m δm( 238 U 92+ ) =2 ev

8 Cryogeni FT-ICR detetion with single ion sensitivity Pikup-Elektrode y x I ion urrent signal mass spetrum p t f Pikup-Elektrode very small signal ~fa Signal-to-noise ratio: r ion : ion motion radius S N FT-ICR Fourier-Transform-Ion Cylotron Resonane q D: trap dimension q: harge state Q: quality fator T: temperature C: apaity = π 2 rion D Q kt C

Already available in Mainz Preision trap 1 m ± 1 µm Mahined at

61(12) Hz 0,1 Amplitude AU 0,01 S = I ion R Q R = 2πC Q =

9 Already available in Mainz Preision trap 1 m ± 1 µm Mahined at the Institute for Mirotehnique Mainz Ring eletrode Single-ion sensitivity! Resonane of the unloaded LC-iruit at T = 4K = (12) Hz 0,1 Amplitude AU 0,01 S = I ion R Q R = 2πC Q = C. Weber et al., Eur. Phys. J A 25, 65 (2005) Amplifiation: E Frequeny / Hz

10 Monitoring Trap Tehnique U = 1 qeb 2π m t 2 B Referene Referene Tehnique 2 B t 1 t 2 t 3 Monitor t 2

Estimated S/N ratio, Cooling times τ, -available.

11 endap orretion ring Status Ideal trap: C 2 =1, C k(even)>2 =0 C 4 0, gives ω z shift Simulations, field alulations -done. Estimated S/N ratio, Cooling times τ, -available. Trap dimensions, -alulated, Magnet is speified, prie quotation, -available.

12 Summary & Outlook The road to high preision & auray with the new 4-trap spetrometer Preision eletrodes, 1m±5µm Compensation eletrodes, C4, C6, D2 << Stable voltage soure, eg. standard ell, 100 nv in 10 V Strong, homogeneous and stable B-field, B=7 T, δb/b<10-7 /m 3, (δb/dt) (1/B)<10-10 /h Cooling, T=4.2 K High Q-value iruit, Q>15000 UHV- vauum, P<10-12 mbar single HCI, Working programe and time table Design study; numerial simulations; field alulations; magnet speifiations, CAD drawings of Penning traps Magnet ordering; ryostat speifiations and drawings; trapmahining; final design for resonane iruits, beam transport in SIMION, off line ion soure onstrution Magnet omissioning; ryostat alignement, experimental hamber alignment versus B, tests at 4.2 K Control and data aquisition system; omissioning the full setup, first test with real ions from offline soure; single ion detetion tests Test measurements with singly harged ions, determination of systemati unertainties, preparation for HCI 20XX Spetrometer is ready to take HCI beam

13 Aknowledgements My olleagues from the MATS group at UNI-MAINZ, and all o-workers from GSI are aknowledged! Thanks for to: VH-NG-037

Atomic Physics with Stored and Cooled Ions

Lecture #8 Atomic Physics with Stored and Cooled Ions Klaus Blaum Gesellschaft für Schwerionenforschung, GSI, Darmstadt and CERN, Physics Department, Geneva, Switzerland Summer School, Lanzhou, China,