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Nuclear physics: the ISOLDE facility

Nuclear physics: the ISOLDE facility. Lecture 2: CERN-ISOLDE facility. Magdalena Kowalska CERN, PH-Dept. kowalska@cern.ch on behalf of the CERN ISOLDE team www.cern.ch/isolde. Outline. Aimed at both physics and non-physics students. Lecture 1: Introduction to nuclear physics

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Nuclear physics: the ISOLDE facility

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  1. Nuclear physics:the ISOLDE facility Lecture 2: CERN-ISOLDE facility Magdalena Kowalska CERN, PH-Dept. kowalska@cern.ch on behalf of the CERN ISOLDE team www.cern.ch/isolde

  2. Outline Aimed at both physics and non-physics students • Lecture 1: Introduction to nuclear physics • This lecture: CERN-ISOLDE facility • Types of radioactive ion beam facilities • ISOLDE within CERN • Beam production at ISOLDE • Lecture 3: Physics of ISOLDE

  3. Open questions in nuclear physics 2 kinds of interacting fermions How to answer the questions: Study nuclei with very different numbers of protons and neutrons (NuPECC long-range plan 2010)

  4. RIB facilities • Two main types of (complementary) RIB facilities: • ISOL (Isotope Separation On-Line) and In-Flight RIB: Radioactive Ion Beam Rare Isotope Beam Light beam heavy beam

  5. RIB facilities comparison

  6. RIB facilities worldwide • Existing and in preparation ISOL-type In-Flight After B. Sherill

  7. ISOLDE – short history Accepted December 1964 First beam October 1967 Upgrades 1974 and 1988 New facility June 1992

  8. ISOLDE at CERN

  9. ISOLDE within CERN accelerators ISOLDE PSB PS LINAC2

  10. ISOLDE elements Isotope production via reactions of light beam with thick and heavy target RIB at 60 keV (post-accelerator) RIB at 3-5 MeV/A 1 Magnetic separators Targets Production – ionization – separation

  11. Ion beam intensity • Number of extracted ions (yield) is governed by: primary particle flux x reaction cross section x number of target particles x efficiencies According to Ulli Koester:

  12. Production channels

  13. Reaction probability • Primary beam type and energy are important

  14. Reaction probability

  15. Production targets p+ p+ p+ p+ p+ p+ • Over 20 target materials and ionizers, depending on beam of interest • U, Ta, Zr, Y, Ti, Si, … • Target material and transfer tube heated to 1500 – 2000 degrees • Operated by robots due to radiation Target Target Converter Converter Target Standard

  16. Inside a standard target

  17. Ionization • Surface • Plasma • Lasers After U. Koester

  18. Beam extraction and separation • All produced ions are extracted by electrostatic field (up to 60kV) • The interesting nuclei are mass selected via magnetic field • Lorentz force: depends on velocity and mass • m/dm <5000, so many unwanted isobars also get to experiments U To experiments = =

  19. Production, ionization, extraction target Target+ vacuum+ extraction Ion energy: 30-60keV robots

  20. Separation Magnet separators (General Purpose and High Resolution)

  21. Post-acceleration Increase in charge state A/q selection Ion trapping and cooling REX accelerator Rf acceleration 3MeV*A beam to experiment

  22. Production and selection - example Facility

  23. Example – astatine isotopes • How to produce pure beams of astatine isotopes (all are radioactive)? • Use lasers to ionize them • And determine for the first time the At ionization potential S. Rothe et al, Nature Communications 4 (2013), 1835

  24. Extracted nuclides More than 700 nuclides of over 70 chemical elements delivered to users (>1100 identified) – by far largest choice among ISOL-type facilities (experience gathered over 45 years)

  25. Experimental hall Decay spectroscopy Coulomb excitation Transfer reactions Laser spectroscopy Beta-NMR Penning traps Target stations HRS & GPS PS-Booster 1.4 GeV protons 3×1013ppp Mass-sep. HRS WITCH ISCOOL RILIS REX-ISOLDE VITO Travelling setups NICOLE Post-accelerated beams MINIBALL and T-REX Collection points Travelling setups COLLAPS CRIS ISOLTRAP TAS IDS

  26. Facility photos

  27. Experimental beamlines

  28. HIE-ISOLDE upgrade High Intensity and Energy ISOLDE Works on-going First post-accelerated beam in 2015/2016

  29. ISOLDE techniques and physics topics protons neutrons Nuclear physics and atomic physics Material science and life sciences Ion traps Decay spectro-scopy Laser spectro-scopy decay pattern mass Transition probability Spin, parity e-m moments half-life radius Nucleon-transfer reactions Beta-detected NMR Coulomb excitation Fundamental interactions Nuclear astrophysics

  30. Summary • Two complementary types of RIB facilities • ISOL and in-flight • Several dozen facilities worldwide and new ones coming • ISOLDE at CERN • ISOL-type facility which uses protons from PSB • Elements: production target, ionization, extraction, separation, (post-acceleration) • Largest variety of beams worldwide • Upgrade project: HIE-ISOLDE • ISOLDE research topics: • Nuclear physics • Atomic physics • Nuclear astrophysics • Fundamental studies • Applications • => Lecture 3

  31. Research with radionuclides 34Ne: 10 protons + 24 neutrons Does it exist? ? = Mean field relative abundance fp-shell 28 20 sd-shell mass 8 p-shell 2 s-shell Nuclear physics Strong interaction in many-nucleon systems Nuclear driplines Astrophysics Nucleo-synthesis, starevolution Abundances of elements Fundamental studies Beyond standard model (neutrino mass, …) Applications, e.g. Solid state physics, life sciences

  32. Properties of radio-nuclides • Different neutron-to-proton ratio than stable nuclei leads to: • New structure properties • New decay modes => Nuclear models have problems predicting and even explaining the observations • Example - halo nucleus 11Li: • Extended neutron wave functions make 11Li the size of 208Pb • When taking away 1 neutron, the other is not bound any more (10Li is not bound)

  33. EURISOL • Future European RIB facility

  34. Isotope identification in-flight

  35. REX post-accelerator • EBIS • Super conducting solenoid, 2 T • Electron beam < 0.4A 3-6 keV • Breeding time 3 to >200 ms • Total capacity 6·1010 charges • A/q < 4.5 • Nier-spectrometer • Select the correct A/q and separate the radioactive ions from the residual gases. • A/q resolution ~150 REXEBIS MASS SEPARATOR Optional stripper ISOLDE ISOLDE beam Primarytarget 7-GAP RESONATORS 9-GAP RESONATOR IH RFQ Rebuncher 60 keV 0.3 MeV/u 3.0 MeV/u 2.2 MeV/u 1.2 MeV/u REXTRAP Experiments • REX-trap • Cooling (10-20 ms) • Buffer gas + RF • (He), Li,...,U • 108 ions/pulse • (Space charge effects >105) Linac Length 11 m Freq. 101MHz (202MHz for the 9GP) Duty cycle 1ms 100Hz (10%) Energy 300keV/u, 1.2-3MeV/u A/q max. 4.5 (2.2MeV/u), 3.5 (3MeV/u) Total efficiency : 1 -10 % 18 May 2009 New opportunities in the physics landscape at CERN 35

  36. HIE-ISOLDE Quarter-wave resonators (Nb sputtered) • SC-linac between 1.2 and 10 MeV/u • 32 SC QWR (20 @ b0=10.3% and 12@ b0=6.3%) • Energy fully variable; energy spread and bunch length are tunable. Average synchronous phase fs= -20 deg • 2.5<A/q<4.5 limited by the room temperature cavity • 16.02 m length (without matching section) • No ad-hoc longitudinal matching section (incorporated in the lattice) • New beam transfer line to the experimental stations

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