The ion trap facility SHIPTRAP at GSI Status and Perspectives Michael Block for the SHIPTRAP collaboration

Outline Introduction SHIPTRAP layout Stopping cell efficiency measurements Penning trap performance Perspectives for mass measurements Summary Outlook – FT-ICR

target wheel primary a few MeV/u fusion a few 100 keV/u detector mass measurements laser spectroscopy ion chemical reaction studies in-trap decay experiments 100 Sn SHE SHIP SHIPTRAP physics program: precision measurements with heavy ions produced at SHIP:

SHE half-lives G. Audi et al. / Nuclear Physics A 729 (2003) 3–128 Above Fm (Z=100) more than 90 nuclides have a half-life > 100ms suitable for trap experiments Fm

SHE mass precision G. Audi et al. / Nuclear Physics A 729 (2003) 3–128 only very few masses known from decay chains Z=112 N=168

The SHIPTRAP set-up Stopping Cooling Accumulation Purification Measurement

SHIPTRAP stopping cell LMU München PhD thesis J. Neumayr to buncher SHIP beam

Efficiency measurements with longitudinal extraction: Reaction: 121 Sb( 35 Cl,4n) 152 Er 152 Er: T 1/2 =10.3s, E  =4.8 MeV Test beam line at MLL-Garching Target: 260 µg/cm² Primary beam energy : 150 MeV Beam intensity:~ 4.5x10 9 s-1 Recoil energy:28.4 MeV Entrance window:Ti 4 µm / 1.8 mg/cm² efficiency for longitudinal extraction  tot = 8.4 % ± 1.5 %

Efficiency measurements with the Ortho-TOF mass spectrometer PhD thesis S. Eliseev Stopping cell and extraction RFQ efficiency for atomic ions:  tot = 4.0 % ± 1.0 % Munich beam time 08/2003 Primary beam: MeV mass resolving power up to 20,000 efficiency 1-3% vacuum problem

Stopping and extraction efficiency for perpendicular extraction 4.8% efficiency 2.7% efficiency Extraction RFQ Stopping Cell fusion products from SHIP Buncher Silicon Detector Silicon Detector  -spectrum behind extraction RFQ 152 Ho 152 Er 153 Er GSI beam time 11/2003 Reaction: 116 Sn( 40 Ar,4n) 152 Er Target: 440 µg/cm² Primary beam energy : 4.2 MeV/u Entrance window:Ti 4 µm 1.8 mg/cm²

stopping cell efficiency measurements test ionefficiencyextraction fields DC / funnel extraction MLL 152 Er  -emitter 8.4 % ± 1.5 %10 V/cm 0o0o GSI 152 Er  -emitter 4.8 % ± 0.7 %10 V/cm 5 V/cm90 o MLL 107 Ag + atomic ions 4.0 % ± 1.0 %5 V/cm 10 V/cm0o0o

Performance of the RFQ Buncher efficiency: in transmission mode: 95 % in bunched mode: 40 % cooling time: ~3 ms emittance (2.5 keV): longitudinal: 5 eV µs transversal: 20  mm mrad PhD thesis: D. Rodríguez M. Mukherjee

SHIPTRAP Penning trap system purification trapmeasurement trap PhD thesis: G. Sikler, S. Rahaman constructed in collaboration with Jyväskylä In the framework of EXOTRAPS 8-fold segmented ring electrode 8-fold segmented ring electrode correction electrodes

Penning trap performance mass resolving power > 80,000 for 133 Cs (total cycle 400ms) purification trap measurement trap mass resolving power > 850,000 for 133 Cs 133 Cs excitation time 200ms

SHIPTRAP - Current Performance ~1% efficiency 4.8% efficiency ~ 5ms extraction time access to nuclei with: production cross section ~ 1  b half-life > 100ms expected precision ~  m/m > 860,000 ~ 1s cycle time  m/m > 80,000 ~400ms cycle time 2.7% efficiency ~ 3ms cooling time

taken from S. Hofmann and G. Muenzenberg, Rev. Mod. Phys., Vol. 72, No. 3, July 2000 Perspectives on direct mass measurements of SHE cross section overall efficiency required beam time 10  b 1 %~ 0.28h 10 %~ 0.03h 1  b 1 %~ 2.8 h 10 %~ 0.28 h 100 nb1 %~ 28 h 10 %~ 2.8 h 10 nb1 %~ 11.5 d 10 %~ 28 h for a precision of using the TOF method

First mass measurements in the region A=150 G. Audi et al. / Nuclear Physics A 729 (2003) 3–128 The numbers give the mass precision in keV

half-lives

Calculated yields for Lu isotopes and A=157 isobars at SHIP Reactions: 58 Ni Pd 157 X + xnyp 58 Ni + 96 Ru A-x-1 Lu + pxn T 1/2 : 46ms 80.6ms 650ms 900ms 6.8s 115ms 10.1ms

Summary Stopping cell efficiency 5%, extraction time ~ 5ms RFQ buncher: 40% efficiency, ~ 1ms cooling time Purification trap: mass resolving power > 80,000 Measurement trap: mass resolving power > 860,000 All individual components operational and characterized: Gas cell and extraction RFQ successfully operated in beam times at GSI and MLL: Overall efficiency of the stopping cell and extraction RFQ 5% Overall efficiency including the RFQ buncher 2.7% First mass measurements can be performed in 2004

Outlook (I) - Improving the efficiency investigate loss mechanisms inside the gas cell reduce neutralization and molecule formation by impurities use higher buffer gas pressure and thinner entrance windows higher extraction fields (e.g. different funnel) change from 90 degree to longitudinal extraction optimize transfer from gas cell to Penning traps improve detection efficiency (Dali detector, channeltron) non destructive detection (FT-ICR)

Outlook (II) - FT-ICR detection

FT-ICR detection : signal-to-noise ratio for a single ion Requirements for a high sensitivity (q = 1, A ≈ 250): large ion radius small trap size high quality factor Q low temperature low capacitance

FT-ICR AT SHIPTRAP 7 T - Magnet Measurement TrapPurification Trap 4K Electronics 77K Filter Bank FFT Analyser Broad Band FFT Analyser narrow-band FT-ICR detection: highly sensitive mass spectrometry on rare nuclei broad-band FT-ICR detection: identification of the trap‘s contents study of chemical reaction kinetics 77 K S. Stahl, PhD thesis C. Weber

THE CRYOGENIC PURIFICATION TRAP

Thank you for your attention!

SHIPTRAP collaborators GSI / SHIPTRAP M. Block D. Beck F. Herfurth H.-J. Kluge C. Kozhuharov M. Mukherjee W. Quint S. Rahaman C. Rauth M. Suhonen C. Weber GSI / SHIP D. Ackermann F. P. Hessberger S. Hofmann G. Münzenberg Greifswald M. Breitenfeld G. Marx L. Schweikhard Mainz H. Backe A. Dretzke R. Horn T. Kolb W. Lauth Giessen S. Eliseev H. Geissel C. Scheidenberger M. Petrick W. Plaß Z. Wang Munich D. Habs S. Heinz J. Neumayr P. Thirolf Former PhD students J. Dilling G. Sikler D. Rodríguez

Magnetron motion: E x B drift Axial motion: oscillation in E-field Reduced cyclotron motion: Penning trap basics r 0 z 0 Ф0Ф0 B for mass measurements: