GSI. Overview of last years activities: technical developments and investigations mass measurements. TRAPSPEC related tasks and issues

Transcription

1 GSI Overview of last years activities: technical developments and investigations mass measurements TRAPSPEC related tasks and issues Conclusion and outlook Frank Herfurth for the SHIPTRAP collaboration

2 The SHIPTRAP collaboration GSI SHIPTRAP: M. Block M. Dworschak S. Eliseev F. Herfurth H.-J. Kluge G. Maero A. Martín W. Quint C. Rauth G. Vorobjev GSI SHIP: D. Ackermann F. P. Heßberger S. Hofmann M. Mazzocco Munich: Giessen&GSI: D. Habs C. Scheidenberger J. Neumayr W. Plaß M. Sewtz T. Fleckenstein P. Thirolf Mainz: K. Blaum R. Ferrer J. Ketalaer D. Neidherr H. Backe P. Kunz W. Lauth Former PhD students: Greifswald: A. Chaudhuri G. Marx L. Schweikhard Huelva: D. Rodríguez St. Petersburg: Yu. Novikov G. Sikler, C. Weber, M. Mukherjee, S. Rahaman, F. Herfurth - SHIPTRAP 2

3 SHIPTRAP set-up SHIP: Fusion-evaporation reaction products separated in-flight by a velocity filter target wheel primary beam, 3-4 Mev/u beam dump GasCell Extraction RFQ Stopping Cooling & Accumulation Purification Buncher Purification Trap Measurement Measurement Trap Detector F. Herfurth - SHIPTRAP 3

4 The SHIPTRAP Gas Cell Ions stopped in a buffer-gas filled cell; extracted and bunched with a buffer-gas filled RFQ structure GasCell Stopping Cooling & Accumulation J. B. Neumayr et al., Nucl. Instr. Method. B 244 (2006) cm Extraction RFQ Buncher best overall efficiency seen: 2.7 % Detector F. Herfurth - SHIPTRAP 4

5 Beam Time Dec'06 Extraction efficiency off-line (on axis): 11.5 (1.0) % Overall efficiency for 152 Er incl. Buncher RFQ: 1.2 (0.2) % Stopping efficiency: > 10 % F. Herfurth - SHIPTRAP 5

6 Beam Time Dec'06 Identified losses Funnel misalignment Stopping volume (window inhomogenity, miscalculations?) transition region extr. RFQ buncher RFQ F. Herfurth - SHIPTRAP 6

7 Gas Cell Challenge Efficiency Stopping Extraction Purity S. Elissev et al., Nucl. Instr. Meth. B, in print 77K diffusion slowed down i.e. higher extraction efficiency higher electric fields possible most impurities frozen which allows for: easy use of internal DC divider chains organic window materials possible (no bake-out required) F. Herfurth - SHIPTRAP 7

8 The Penning Traps Ion bunches are captured in the purification Penning trap, cooled and purified with isobaric resolution. The mass is measured with the TOF-ICR method in the measurement trap. GasCell Extraction RFQ Stopping Cooling & Accumulation Buncher Purification Measurement purification trap Detector differential pumping barrier (3 x 50 mm) now Ø 1.5 mm measurement trap 20 cm m ion q B = 2 π ν c F. Herfurth - SHIPTRAP 8

9 Octupolar excitation 145 Quadrupolar quadrupolar excitation Excitation 140 Octupolar octupolar Excitation excitation TOF ( µs) _ + + _ 10.6(2) Hz N=690 ions ν RF (Hz) Proven Gain compared to quadrupolar excitation: resolution x 10 precision x _ + _ 1.9(1) Hz N=710 ions ν RF (Hz) S. Elissev et al., Int. J. Mass Spectrom. 262 (2007) F. Herfurth - SHIPTRAP 9

10 Measurements along the rp-process process Xe(54) # I(53) # # # # Te(52) # # Sb(51) # # # # # # Sn(50) # # # In(49) # # # # Cd(48) # # # # Ag(47) # # # # 58 Pd(46) # # # # # 56 Rh(45) # # # # # # 54 Ru(44) # # # # # # 52 Tc(43) # # # # # Mo(42) # # # ANL Nb(41) # # JYFL Zr(40) # # # SHIPTRAP F. Herfurth - SHIPTRAP 10 60

11 rp Process Masses 2006 calculated cross section ~ 20 µbarn rp process path 82 joint proposal JYFLTRAP - SHIPTRAP Reaction: 40 Ca+ 58 Ni R. Ferrer et al. - measured at SHIPTRAP - first time F. Herfurth - SHIPTRAP 11

12 rp Process Masses 50 Cr+ 58 Ni MeV/u 58 Ni+ 58 Ni MeV/u 24 masses measured, 23 entered the atomic mass evaluation (AME) and 20 more masses affected. δm/m between and The data are consistent (the reduced χ 2 for SHIPTRAP is 1.076). A. Martín et al F. Herfurth - SHIPTRAP 12

13 rp Process Masses 113 Xe 109 Te, 105 Sn α 109 Te α Q α 105 Sn Q α : (40) kev (15) kev (30) kev SHIPTRAP 3193 (10) kev A. Martín et al F. Herfurth - SHIPTRAP 13

14 Tasks within EURONS-TRAPSPEC Development of detectors for in-trap decay Simulation in order to establish a detector concept Cryogenic Penning trap Design, Simulation to check B-field homogeneity, construction Data acquisition and control system definition, installation of hardware, development of software, test Tests and measurements General delay due to a quench of General the SHIPTRAP delay due magnet to another in March'06 quench of ( > the 3 Months) SHIPTRAP magnet (total delay > 2 x 3 Months) F. Herfurth - SHIPTRAP 14

15 Cryogenic Penning Trap(s) Three cryogenic traps are under construction FT-ICR trap for SHIPTRAP electronics at 4K, differential pumping at 77K to be tested offline using new superconducting magnet HITRAP cooler trap electronics and differential pumping at 4K HITRAP laser spectroscopy trap open trap structure for radiation detection F. Herfurth - SHIPTRAP 15

16 The SHIPTRAP Cryogenic Trap Purification Trap Superconducting 7 T Magnet He - Cryostat with Superconducting 4 K 300 K Nitrogen Reservoir 77K 77 K Ion Beam Pumping Barrier Measurement Trap C. Weber F. et Herfurth al., Eur. -Phys. SHIPTRAP J. A. 25, suppl. 1, 65 (2005) 16 1,94 m isolation vacuum chamber Status and Details Jens Ketalaer trap vacuum chamber

17 The Cooler Trap of 4K Magnet available Electrode design finished, being machined Electronics container available, electronics components being tested Flexible power supplies production finished F. Herfurth - SHIPTRAP 17

18 Software Developments CS advanced to version 3.1 (based on LabView 8.2) Dietrich Beck et al. communication now using DIM (faster, better scalable, more reliable, publisher-subscriber model) FPGA programming for flexible timing control finished Stephen Koszudowski et al F. Herfurth - SHIPTRAP 18

19 Conclusion and Outlook The SHIPTRAP facility is operating routinely with an overall efficiency of up to ~0.5%. In five beamtimes the masses of 52 nuclides (18 new ones) were measured with uncertainties Improve: Efficiency Gas cell (cryogenic) Detection (FT-ICR) Precision F. Herfurth - SHIPTRAP 19

20 Real Schedule '06 Exp. Feb Quench March Reinstallation April June Exp. July Octupolar excitation & Inhomogenity Measurements (Aug/Sep) Quench October Reinstallation Nov. Feb. Gas cell test run Dec F. Herfurth - SHIPTRAP 20