Atomic Physics with Stored and Cooled Ions

Transcription

1 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, 9 17 August Lecture: Future techniques and experiments 1. Future trap experiments 2. The GSI future project 3. Other worldwide projects

2 The mass spectrometer TITAN at ISAC Precision measurements on very short-lived nuclides. ISAC ion beam RFQ cooler & buncher EBIT charge breeder m/q selection Penning trap 10 times higher yield as compared to ISOLDE 1 50 times higher resolving power as compared to 1+ factor of shorter half-lives accessible much higher resoving power and accuracy saving in beam time requirement δm/m < on isotopes with T ½ 10 ms perfect match with ISOL capabilities J. Dilling, P. Bricault, M. Smith, H.-J. Kluge, et al.

3 The mass spectrometer SHIPTRAP at GSI Precision measurements on very heavy elements at low production rates. Stopping Cooling Accumulation Purification 1 2 Measurement 3 4 Stopping Cell fusion products from SHIP Extraction RFQ Buncher 3 Purification Trap 4 Measurement Trap 6 5 K. Blaum, M. Block, M. Mukherjee, H.-J. Kluge, D. Rodriguez, S. Rahaman, W. Quint, C. Weber, et al. Detector Downstream Experiments

4 The laser ion source trap LIST K. Wendt, K. Blaum, C. Geppert, K. Brueck, H.-J. Kluge, M. Mukherjee, S. Schwarz, K. Wies Ion Repeller Atom source Laser- Beams Ti:Sa 1 Proton beam Gas filled RFQ Trap Ion Beam Ti:Sa 2 Ti:Sa 3 HV Platform to Experiments Nd:YAG 1. Atom Source with Ion Repeller 3. Mass Separator 2. Gas filled RFQ Trap Section 4. Laser System Very high element and isobaric selectivity.

5 The HITRAP project at the ESR UNILAC experiments for slow particles postdecelerator experiments cooler with particles Penning at rest trap U 92+ EXPERIMENTS WITH WITH HIGHLY CHARGED IONS IONS AT AT EXTREMELY LOW LOW ENERGIES: high-accurate mass mass measurements g-factor g-factor measurements fundamental constants constants laser laser and and x-ray x-ray spectroscopy of of few-electron systems systems nuclear nuclear polarization diamagnetic correction SIS stripper target ESR electron cooling and deceleration down to 7 MeV/u 400 MeV/u U 73+ U 92+

6 Future personal projects Novel Penning trap setup for ultra high-precision mass spectrometry with δm/m Help to place limits on the electron neutrino rest mass, e.g. Q( 3 T(β) 3 He) for the KATRIN experiment Determination of e-binding energies for QED tests Measurement of fundamental constants Metrology, e.g. new kilogram definition... Trap developments for the investigation of exotic atomic and nuclear systems g-factor measurement of the antiproton (HITRAP) antihydrogen studies (FLAIR)

7 Novel high-precision penning trap mass spectrometer Proposed setup: 7 T - MAGNET - WITH THREE HOMOGENEOUS CENTERS He - CRYOSTAT WITH SUPERCONDUCTING INDUCTIVITY 4 K IONS FROM ION SOURCES LHe- RESERVOIR 4 K 300 K DETECTOR 3 PRECISION TRAPS VACUUM SYSTEM Timing scheme: T 1 trap 1 trap 2 trap 3 Advantages: T 2 T 3 3 He 3 T Direct mass doublet measurement. No ion-ion interaction. T 4 Simultaneous measurement process.

8 Technical challenges Detection technique: Cryogenic FT-ICR Signal to noise ratio: S N = π 2 r D ion q ν ν Q kt C r ion : ion motion radius D: trap dimension q: charge state Q: quality factor T: temperature C: capacity First requirements: Superconducting, temperature stab. magnet with B ~ 7T Homogenous trap region with db/b<10-10 active shielding, 3-axis compensation coils,... three high-precision cryogenic Penning traps Cryogenic phase sensitive FT-ICR detection Ultra-high vacuum for long storage and interaction times Goal: δm / m

9 First application of the planned penning trap system Determination of the of 3 T - 3 He mass difference with a precision of ~20 mev for the KATRIN experiment (present absolute precision is 1.7 ev) in discussion with C. Weinheimer et al. m n = 0 ev E 0 m n = 1 ev ~ 2 * KATRIN LOI: If a 1ppm precision ( 20 mev) in the 3 He-T mass difference M ( 3 He,T) and the absolute calibration of KATRIN could be achieved the sensitivity on m ν could be improved further by using an external M ( 3 He,T) value in the analysis.

10 Detection of single-quantum excitation 3 T + / 3 He + 24 Mg + sideband cooling laser 3 T + / 3 He + 24 Mg + energy exchange sideband cooling + detection single quantum excitation energy exchange detector B = 7 T ν c ( 24 Mg + ) = 4.4 MHz ; ν c ( 3 He + ) = 35 MHz choose ν z ( 3 He + ) = 4.4 MHz

11 Facility for Low-energy Antiproton and Ion Research FLAIR SIS 100/300 NESR beam SIS UNILAC FRS HESR ESR CR RESR 100 m FL AI R Super FRS NESR Factor 100 more pbar trapped or stopped in gas targets than now

12 The Super-FRS facility at FAIR The future GSI project: FAIR Facility for Antiproton and Ion Research Low-Energy Branch Super-FRS High-Energy Branch Ring Branch

13 Chapter 9 Atomic Physics with Stored and Cooled Ions Klaus Blaum Gesellschaft für Schwerionenforschung, GSI, Darmstadt and CERN, Physics Department, Geneva, Switzerland Summer School, Lanzhou, China, 9 17 August Chapter: Summary and conclusions

14 Conclusions and Outlook Ion traps are an ideal tool to perform atomic and nuclear physics precision experiments! There are a high number of trap/storage devices at present in operation, under construction or planned. Impressive results have been obtained with stored and cooled ions in the past, e.g. measurements of masses, g factors, fundamental studies, test of WI,. Future trap experiments aim for δm/m < for stable ions and can thus help to discover exciting new physics The future GSI facility with HITRAP and FLAIR opens exciting possibilities for trap experiments, e.g. with antiprotons and antihydrogen

15 Final Conclusion Heinz Maier-Leibnitz ( ) Whenever you invent a method ten or a hundred times better than the existing ones, you can be sure that this will lead to new science!