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Portuguese groups at ISOLDE - CERN Ulrich Wahl Instituto Tecnológico e Nuclear (ITN) Sacavém Instituto Tecnológico e Nuclear (ITN) Sacavém Centro de Física.

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Presentation on theme: "Portuguese groups at ISOLDE - CERN Ulrich Wahl Instituto Tecnológico e Nuclear (ITN) Sacavém Instituto Tecnológico e Nuclear (ITN) Sacavém Centro de Física."— Presentation transcript:

1 Portuguese groups at ISOLDE - CERN Ulrich Wahl Instituto Tecnológico e Nuclear (ITN) Sacavém Instituto Tecnológico e Nuclear (ITN) Sacavém Centro de Física Nuclear da Universidade de Lisboa (CFNUL) ISOLDE and Nuclear Solid State Physics ISOLDE and Nuclear Solid State Physics Portuguese experiments at ISOLDE: history, people, collaborations Portuguese experiments at ISOLDE: history, people, collaborations Examples: - position-sensitive electron detector development - emission channeling lattice location of Fe in Si - PAC investigation of O and F in High-Tc Hg-1201 Examples: - position-sensitive electron detector development - emission channeling lattice location of Fe in Si - PAC investigation of O and F in High-Tc Hg-1201 Conclusions amd outlook Conclusions amd outlook

2 The ISOLDE on-line isotope separator Available beams: ~ 600 isotopes of ~ 70 elements 1 GeV protons radioactive ion beams mass separation 60 keV acceleration target and ion source

3 Weak Interaction and Nuclear Physics 46% Solid State Physics 22% Particle and Astro-Physics 13% Biology/Medicine 5% Atomic Physics 15% ISOLDE Experiments Experiments 300 Users 96 Institutes 22 Countries 375 8h-shifts of radioactive beams Experiments involving Portuguese groups: typically around shifts per year i.e. ~3% of ISOLDE availability

4 Experimental techniques used with radioactive isotopes at ISOLDE Portuguese groups: emission channeling (EC) perturbed angular correlation (PAC)

5 2000 IS390 Studies of colossal magnetoresistive oxides with radioactive isotopes ~2005 spokesperson V. Amaral (U Aveiro) 1998 IS368 Lattice location of transition metals and rare earths in semiconductors ~2006 spokesperson U. Wahl (ITN & CFNUL, then IKS Leuven) 1997 IS360 Studies of high-Tc superconductors with radioactive isotopes ~2006 spokesperson J.G. Correia (ITN & CFNUL) 1986 e- PAC at ISOLDEIS01/13spokesperson J.C.Soares 1994 Test of new PAC probes IS-P66spokesperson J.G. Correia e - PAC 197m Hg, 73 Ge, 127 Cs, 80 Br 2001 New improved electron emission channeling pad detectors and development of self-triggering front-end electronics Cooperation agreement between ITN, CFNUL and CERN EP-ATT Group (now: PH-TA1) History of e - PAC and EC at ISOLDE-CERN

6 Network of groups involved CFNUL Lisbon Prof. José C. Soares Prof. Manuel. R. Silva 2 PhD students: Elisabete Rita Ana C. Marques 1 Diploma student: Sonia Dias Dr. J. Guilherme Correia Dr. Ulrich Wahl Dr. Heinz Haas (retired) ITN Sacavém University of Aveiro Prof. Vitor Amaral Dr. Mario S. Reis 1 PhD student: Armandina Lopes 1 Diploma student: João C. Amaral University of Porto Prof. J. Pedro Araújo 1 Masters student: Tania Mendonça KU Leuven (Belgium) Prof. André Vantomme 2 PhD students: Bart De Vries Stefan Decoster LEUVEN Univ. of Kwazulu Natal (South Africa) Prof. Krish Bharuth-Ram University of Göttingen (Germany) Prof. Hans Hofsäss (future collaboration) CERN Dr. Peter Weilhammer (detector development)

7 Funding: mainly from national sources CFNUL Lisbon Portuguese Foundation for Science & Technology (dedicated CERN project on PAC & emission channeling) ITN Sacavém University of Aveiro University of Porto KU Leuven (Belgium) Fund for Scientific Research - Flanders (dedicated project on emission channeling) Univ. of Kwazulu Natal (South Africa) University of Göttingen (Germany) Federal Ministry of Education and Research (dedicated project on emission channeling) CERN Portuguese Foundation for Science & Technology (dedicated CERN project on magnetic oxides)

8 [-1102] [0001] Arsenic occupies multiple sites in ZnO Collaboration: ITN, CFNUL & CERN PH-TA1 group Future detectors: pads self-triggering 5 keV trigger 10 kHz readout Cooled 2 o C Position-sensitive Si pad detectors for Emission Channeling 73 As in ZnO low electron energy

9 Lattice site changes of implanted 59 Fe in Si U. Wahl et al., accepted by Phys. Rev. B Fe is gettered by at least two types of vacancy-like defects Following release to interstitial state re-gettering occurs at a different gettering center on ideal substitutional sites as-implanted: mainly displaced substitutional Fe annealed at T=300°C: mainly tetrahedral interstitial Fe annealed at T=800°C: mainly ideal substitutional Fe

10 Oxygen & Fluorine Configurations in Hg1201 (High-Tc) HgBa 2 CuO 4+ Tc > 92K Radioactive ions PAC Experiment Electric Field Gradient dopant configuration fingerprint ~ (Mrad/s) EFG Simulations J.G. Correia et al., submited to Phys. Rev. B

11 Currently and near future (till ~2006): IS368: Lattice location in semiconductors, e.g. IS368: Lattice location in semiconductors, e.g. Si, Ge, SiGe, diamond, III-V, nitrides, II-VI, ZnO… electrical doping, transition metals, rare earths, diluted magnetic semiconductors Si, Ge, SiGe, diamond, III-V, nitrides, II-VI, ZnO… electrical doping, transition metals, rare earths, diluted magnetic semiconductors IS360: PAC in High-Tc superconductors IS360: PAC in High-Tc superconductors IS390: Magnetism in manganites (CMR) IS390: Magnetism in manganites (CMR) Conclusions and outlook: After 2006: New emission channeling proposal(s) applying… new position-sensitive detectors (self-triggering pad, CCD) new position-sensitive detectors (self-triggering pad, CCD) - on-line experiments with short-lived isotopes - low energy electron emitters (Auger electrons?) a new variety of elements (e.g. Mg, Co, Ni, Zn, Ge) will be available for emission channeling - on-line experiments with short-lived isotopes - low energy electron emitters (Auger electrons?) a new variety of elements (e.g. Mg, Co, Ni, Zn, Ge) will be available for emission channeling


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