ROGER CABALLERO FOLCH, 1 de juny de 2012. Introduction: Astrophysics and Nuclear Physics motivation Experiment: Setup and detectors BEta deLayEd Neutron.

Slides:



Advertisements
Similar presentations
New technique to determine beta half-lives in complex background conditions T. Kurtukian-Nieto 1, J. Benlliure 1, K.-H. Schmidt 2, L. Audouin 3, F. Becker.
Advertisements

Roger Caballero-Folch (DFEN –UPC) València, 15 de juliol de 2013 β-decay half-lives and β- delayed neutron emission measurements for r-process nucleosynthesis.
ROGER CABALLERO FOLCH, FRS User meeting GSI, 28 th November 2011 S410 EXPERIMENT GSI – SEPTEMBER 2011.
ROGER CABALLERO-FOLCH Universitat Politècnica de Catalunya 26 de febrer de 2013 NUSTAR ANNUAL MEETING GSI Darmstadt, Germany Beta dELayEd Neutron.
GEANT4 Simulations of TIGRESS
Γ spectroscopy of neutron-rich 95,96 Rb nuclei by the incomplete fusion reaction of 94 Kr on 7 Li Simone Bottoni University of Milan Mini Workshop 1°-
LLNL-PRES-?????? This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344.
University of Surrey Nuclear Physics Research Group Nuclear theory group (2 Professors (Al-Khalili & Tostevin) ; 2 Senior Lecturers (Stevenson & Barbieri),
J. Pereira  -decay studies of r-process nuclei near 137 Sb Jorge Pereira NSCL/MSU Frontiers 2005, MSU, August 2005.
ROGER CABALLERO FOLCH, Barcelona, 9 th November 2011.
Teresa Kurtukian-Nieto Centre d’Etudes Nucléaires de Bordeaux Gradignan Precision half-life determination of the superallowed 0 + → 0 + β + -emmiters 42.
The BEta deLayEd Neutron emission measurements
Status of TACTIC: A detector for nuclear astrophysics Alison Laird University of York.
UNIVERSITY OF JYVÄSKYLÄ Lifetime measurements probing triple shape coexistence in 175 Au Tuomas Grahn Department of Physics University of Jyväskylä The.
Workshop on Physics on Nuclei at Extremes, Tokyo Institute of Technology, Institute for Nuclear Research and Nuclear Energy Bulgarian Academy.
1 TCP06 Parksville 8/5/06 Electron capture branching ratios for the nuclear matrix elements in double-beta decay using TITAN ◆ Nuclear matrix elements.
The FAIR Chance for Nuclear Astrophysics Elemental Abundances Core-collapse Supernovae The neutrino process The r-process nuclei in -Wind Neutron Stars.
Nuclear Astrophysics with the PJ Woods, University of Edinburgh.
The Inverse Kinematics Resonance Elastic Scattering Reaction of 10,11,12 Be+p Liu Yingdu( 刘应都 ) PHD candidate Advisor : Wang Hongwei, Ma Yugang
Lawrence Livermore National Laboratory Nicholas Scielzo Lawrence Fellow Physics Division, Physical Sciences LLNL-PRES Lawrence Livermore National.
Setups (BELEN, MONSTER  D. Cano-Ott/ CIEMAT) Implantation detector (SIMBA, AIDA (>autumn 2010) ) Beams N=50 (78Ni): 124Sn (?) N=82 (132Sn, 130Cd): 136Xe,
Ciemat Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas D. Cano-Ott DESPEC/HISPEC Coll. Meeting, 15th-16th of June 2005-Valencia.
Clean Beams at ISOL Facilities GSI Workshop on Astrophysics and Nuclear Structure, January 15-21, 2006 in Hirschegg, Austria O.Arndt, H. Frånberg, C.Jost,
1 Reaction Mechanisms with low energy RIBs: limits and perspectives Alessia Di Pietro INFN-Laboratori Nazionali del Sud.
Pygmy Dipole Resonance in 64Fe
Proton emission from deformed rare earth nuclei: A possible AIDA physics campaign Paul Sapple PRESPEC Decay Physics Workshop Brighton 12 January 2011.
1 Alpha Decay  Because the binding energy of the alpha particle is so large (28.3 MeV), it is often energetically favorable for a heavy nucleus to emit.
35 Ca decay beta-delayed 1- and 2-proton spokespersons: J. Giovinazzo (CENBG), O. Tengblab (CSIC) institutions: Centre d’Etudes Nucléaires (Bordeaux) –
1 Beta Counting System Li XiangQing, Jiang DongXing, Hua Hui, Wang EnHong Peking University
Fundamental Interactions Physics & Instrumentation Conclusions Conveners: P. Mueller, J. Clark G. Savard, N. Scielzo.
R-process experiments at the National Superconducting Cyclotron Laboratory Giuseppe Lorusso NSCL at Michigan State university.
European Isotope Separation On-Line Radioactive Nuclear Beam Facility A preliminary design study of the next- generation European ISOL RNB facility GANIL,
DESPEC A Algora IFIC (Valencia) for the Ge array working group.
RNB Cortina d’Ampezzo, July 3th – 7th 2006 Elisa Rapisarda Università degli studi di Catania E.Rapisarda for the Diproton collaboration 18 *
Β decay of 69 Kr and 73 Sr and the rp process Bertram Blank CEN Bordeaux-Gradignan.
 2-proton emission  experimental set-up  decay results  2p emission from 45 Fe  perspectives Jérôme Giovinazzo – CEN Bordeaux-Gradignan – France PROCON’03.
Progress in  half lives of nuclei approaching the r-process path at N=126 José Benlliure Universidad de Santiago de Compostela, Spain INPC 2007.
GAN Zaiguo Institute of Modern Physics, Chinese Academy of Sciences Alpha decay of the neutron-deficient uranium isotopes.
Production and beta decay lifetimes of heavy neutron-rich nuclei approaching the r-process path Teresa Kurtukian-Nieto Universidad de Santiago de Compostela.
NS08 MSU, June 3rd – 6th 2008 Elisa Rapisarda Università degli studi di Catania E.Rapisarda 18 2.
UK Research in Nuclear Physics P J Nolan University of Liverpool.
Radioactive beam spectroscopy of 212 Po and 213 At with the EXOGAM array Nick Thompson University of Surrey.
FAIR (Facility for Antiproton and Ion Research) (Darmstadt, Germany) low-energy cave MeV/u fragmentation/fission ~1GeV/u fragment separator 350m.
Beta decay around 64 Cr GANIL, March 25 th V 63 V 64 V 60 V 61 V 63 Cr 64 Cr 65 Cr 61 Cr 62 Cr 60 Cr 64 Mn 65 Mn 66 Mn 65 Fe 67 Fe 1) 2 + in 64.
J-PARC でのハイパー核ガンマ線分光実験用 散乱粒子磁気スペクトロメータ検出器の準備 状況 東北大理, 岐阜大教 A, KEK B 白鳥昂太郎, 田村裕和, 鵜養美冬 A, 石元茂 B, 大谷友和, 小池武志, 佐藤美沙子, 千賀信幸, 細見健二, 馬越, 三輪浩司, 山本剛史, 他 Hyperball-J.
February 12-15,2003 PROCON 2003, Legnaro-Padova, Italy Jean Charles THOMAS University of Leuven / IKS, Belgium University of Bordeaux I / CENBG, France.
Adam Maj IFJ PAN Krakow Search for Pigmy Dipole Resonance in 68 Ni RISING experiment in GSI EWON Meeting Prague, May, 2007.
1 BETA-DELAYED NEUTRON SPECTROSCOPY OF 51,52,53,(54) Ca A. Gottardo, R. Grzywacz, M. Madurga ISOLDE Workshop2015.
Search for neutron-rich hypernuclei in FINUDA: preliminary results presented by M. Palomba 1 for the FINUDA Collaboration 1 INFN and Dipartimento di Fisica,
The experimental evidence of t+t configuration for 6 He School of Physics, Peking University G.L.Zhang Y.L.Ye.
Decay scheme studies using radiochemical methods R. Tripathi, P. K. Pujari Radiochemistry Division A. K. Mohanty Nuclear Physics Division Bhabha Atomic.
Jun Chen Department of Physics and Astronomy, McMaster University, Canada For the McMaster-NSCL and McMaster-CNS collaborations (5.945, 3+ : **) (5.914,
Albert Riego, Guillem Cortes, Francisco Calviño July 22 th, 2015 Universitat Politecnica de Catalunya, Barcelona (Spain) Third BRIKEN WORKSHOP – IFIC (Valencia,
3 rd BRIKEN WORKSHOP: Welcome! 3 rd BRIKEN WORKSHOP, IFIC, Valencia 22-24/07/2015 C. Domingo-Pardo IFIC (CSIC-University of Valencia)
Recent achievements and future challenges of the Spanish research in experimental nuclear physics José Benlliure Universidad of Santiago de Compostela.
M. B. Gómez et al. SEN, UPC, Barcelona Total Absorption  - Ray Spectrometer: DTAS 4  Neutron Counter: BELEN Neutron Time of Flight Spectrometer: MONSTER.
Advanced Implantation Detector Array (AIDA): Update & Issues Tom Davinson School of Physics The University of Edinburgh presented by Tom Davinson on behalf.
26th September 2014 Guillermo Ribeiro 1 G. Ribeiro, E. Nácher, A. Perea, J. Sánchez del Río, O. Tengblad Instituto de Estructura de la Materia – CSIC,
PANIC’08 Eilat, November 13th, 2008 Teresa Kurtukian Nieto CEN Bordeaux-Gradignan Supernova remnant N49 Photo Credit: Hubble Heritage Team (STScI / AURA),
Report (2) on JPARC/MLF-12B025 Gd(n,  ) experiment TIT, Jan.13, 2014 For MLF-12B025 Collaboration (Okayama and JAEA): Outline 1.Motivation.
Proton emission from deformed rare earth nuclei: A possible AIDA physics campaign Paul Sapple PRESPEC Decay Physics Workshop Brighton 12 January 2011.
The r process: Towards the (experimental) terra incognita
Decay spectroscopy with LaBr3(Ce) detectors at RIKEN and GSI
DSSSD for b decay investigations of heavy neutron-rich isotopes
BEAM INTENSITIES WITH EURISOL
Theme group for b-delayed neutron measurements
The First
MINOS: a new vertex tracker for in-flight γ-ray spectroscopy
1. Introduction Secondary Heavy charged particle (fragment) production
Presentation transcript:

ROGER CABALLERO FOLCH, 1 de juny de 2012

Introduction: Astrophysics and Nuclear Physics motivation Experiment: Setup and detectors BEta deLayEd Neutron detector (BELEN) outlook goals Contents AnalysisBELENIntroductionExperiment Analysis - Ongoing work

Current questions in the field of nuclear physics AnalysisBELENIntroductionExperiment Introduction What are the limits of nuclear existence? What is the heaviest element we can make? Do new forms of collective motion occur far from the valley of nuclear stability? Are there new forms of nuclear matter in very loosely bound nuclear systems? How does the ordering of quantum states, with all of its consequent implications for nuclear structure and reactions, alter in highly dilute or neutron-rich matter? Do symmetries seen in near-stable nuclei also appear far from stability and do we observe new symmetries? How are the elements and isotopes found in the Universe formed? Where are the sites of the r-process(es) of nucleosynthesis? What is the nuclear equation of state for neutron stars? etc, etc. Taken from NUPECC long range plans

Experimental resources Main Experimental Research Activities Nuclear structure and dynamics Nuclear astrophysics Fundamental interactions Nuclear physics tools and applications Main Research Facilities GSI (Germany) ISOLDE (CERN) n_TOFF (CERN) Univ. of Jyväskylä (Finland) INFN-LNL (Italy) GANIL (France) …also installations overseas (TRIUMF, RIKEN, etc.) Laboratories AnalysisBELENIntroductionExperiment Introduction

Nucleosynthesis in nature Fusion in common stars: from H only He & Li are produced CNO cycle. More nuclei with fusion reaction up to Fe. Beyond Fe nucleosynthesis proceeds through: s-process, r-process, p- process, etc AnalysisBELENIntroductionExperiment Introduction

Nucleosynthesis s-process AnalysisBELENIntroductionExperiment Introduction

Nucleosynthesis s-process AnalysisBELENIntroductionExperiment Introduction

Nucleosynthesis s-process AnalysisBELENIntroductionExperiment Introduction

Nucleosynthesis r-process AnalysisBELENIntroductionExperiment Introduction

State of the art: Knowledge of masses through the years Up to 1940 G. Audi et al., Nucl. Phys. A565, 1(1993); A 595, 409 (1995), A (2003) AnalysisBELENIntroductionExperiment Introduction

State of the art: Knowledge of masses through the years Up to 1948 G. Audi et al., Nucl. Phys. A565, 1(1993); A 595, 409 (1995), A (2003) AnalysisBELENIntroductionExperiment Introduction

State of the art: Knowledge of masses through the years Up to 1958 G. Audi et al., Nucl. Phys. A565, 1(1993); A 595, 409 (1995), A (2003) AnalysisBELENIntroductionExperiment Introduction

State of the art: Knowledge of masses through the years Up to 1968 G. Audi et al., Nucl. Phys. A565, 1(1993); A 595, 409 (1995), A (2003) AnalysisBELENIntroductionExperiment Introduction

State of the art: Knowledge of masses through the years Up to 1978 G. Audi et al., Nucl. Phys. A565, 1(1993); A 595, 409 (1995), A (2003) AnalysisBELENIntroductionExperiment Introduction

State of the art: Knowledge of masses through the years Up to 1988 G. Audi et al., Nucl. Phys. A565, 1(1993); A 595, 409 (1995), A (2003) AnalysisBELENIntroductionExperiment Introduction

State of the art: Knowledge of masses through the years Up to 1994 G. Audi et al., Nucl. Phys. A565, 1(1993); A 595, 409 (1995), A (2003) AnalysisBELENIntroductionExperiment Introduction

State of the art: Knowledge of masses through the years Up to 2004 G. Audi et al., Nucl. Phys. A565, 1(1993); A 595, 409 (1995), A (2003) About 2200 nuclear masses were measured and 3000 nuclides known of 8000 that are assumed to exist. Still far away from the r-process path, Especially for the heavy nuclides. Future RIB facilities: FAIR and RIKEN AnalysisBELENIntroductionExperiment Introduction

FAIR (Facility for Antiproton Ion Research) AnalysisBELENIntroductionExperiment Introduction

β,n, γ-decay of exotic (neutron- rich) nuclei... DESPEC requires different types of equipment to study the multiple aspects of the problem  -decay Beta delayed neutron detector Neutron spectrometer with AIDA Fast timing array TAS DESPEC (Decay SPECtroscopy) AnalysisBELENIntroductionExperiment Introduction

Neutron emission after β - decay scheme To measure neutron emission probabilities after beta decay of neutron rich isotopes with relevance in basic nuclear physics, astrophysics and nuclear technology. AnalysisBELENIntroductionExperiment Introduction

neutron BETA Example of β - delayed neutron emission AnalysisBELENIntroductionExperiment Introduction

Motivation Half lives (T 1/2 ) Beta delayed neutron emission probabilities (P n ) Astrophysics (r-process) and nuclear structure: nucleosynthesis aspects of the heavy mass elements. Provide valuable information for the test of theoretical models. Exp. T. Kurtukian et al. Phys. Lett. B (Submitted) DF3 + QRPA + FRDM + QRPA (P.Moeller, et al. 2003) (I.Borzov, et al. 2003) AnalysisBELENIntroductionExperiment S410: Beta-decay measurements of new isotopes near the third r-process peak (N~126)

State of the art N=126 t 1/2 existsidentified Area of interest P n (%) QRPA B n = 2-3 MeV Centered AnalysisBELENIntroductionExperiment

GSI facility. Fragment separator spectrometer (FRS) Beam characteristics 238 U beam 1GeV/n 2x10 9 ions/s intensity 1.6 g/cm 2 Be target AnalysisBELENIntroductionExperiment

Fragment separator spectrometer (FRS). Beam characteristics. SIMBA + BELEN 1.6 g/cm 2 Be target 2x10 9 ions/spill intensity Bρ settings for: 215 Tl, 211 Hg and as references 216 Po, 205 Bi, 135 Sb Spill length ~1s with a period around 4s Separation in flight Bρ – ΔE – Bρ AnalysisBELENIntroductionExperiment

Experimental hall (S4) configuration and setting s TPC MUSIC SLITS SCI DEGRADER ITAG SIMBA & BELEN AnalysisBELENIntroductionExperiment

Neutron detector SIMBA Polyethylene shielding AnalysisBELENIntroductionExperiment Experimental hall (S4) configuration and setting s

Particle Identification (ID) The separation method based in Time of Flight (ToF) measurement, Energy Loss (ΔE) in the (MUSIC) ionisation chambers and the B fields (Bρ) set. AnalysisBELENIntroductionExperiment IDENTIFICATION: Z and A/Z

Implantation detector: SIMBA (Silicon Implantation Detector and Beta Absorber) SIMBA detector Multilayer silicon detector Allows to measure both ion implants and β-decays. Decay events can be correlated in time with the detection of neutrons. 2 SSSD (7 segm.) 60x40 mm 2 (1mm thick) XYFRONTA B CREAR Tracking layers XY (60 segm.) 60x60 mm 2 (0.3mm thick) 2 SSSD (7 segm.) 60x40 mm2 (1mm thick) 3 DSSD (implantation area, 60x40 segm.): 60x40 mm 2 (0.7mm thick) Front view AnalysisBELENIntroductionExperiment

Neutron detector: BELEN (Beta Delayed Neutron Detector) - Neutron detector designed by UPC GRETER research group (Barcelona) - The detection of the neutron is based on the detection of products of the reaction of the neutron with 3He counters: 3 He + n  3 H + 1 H keV Ion beam n n n Polyethylene moderator Proportional 3 He counter Silicon β decay detector He counters: AnalysisBELENIntroductionExperiment

Neutron detector: BELEN (Beta Delayed Neutron Detector) BELEN-30 neutron detector · 10 with 10 atm pressure · 20 with 20 atm pressure Neutron shielding SIMBA inside the matrix BEAMLINE AnalysisBELENIntroductionExperiment

AnalysisBELENIntroductionExperiment Analysis procedure (Preliminary plots / ongoing) Analysis Tracking detectors calibrations & particle ID Particle ID check via 205 Bi isomers, 216 Po α-decays SIMBA calibration implantation patterns Analysis of half lives and Pn Digital data acquisition system features SCI21-SCI41  ToF TPC21-22 – TPC41-42  Position calibration MUSIC  Energy Loss calibration Angle correction of each particle. TPC information.

Tracking detectors calibrations & particle ID Particle ID check via 205 Bi isomers, 216 Po α-decays SIMBA calibration implantation patterns Analysis of half lives and Pn Digital data acquisition system features Analysis procedure (Preliminary plots / ongoing) AnalysisBELENIntroductionExperiment Analysis Physical effects along time correction.

Tracking detectors calibrations & particle ID Particle ID check via 205 Bi isomers, 216 Po α-decays SIMBA calibration implantation patterns Analysis of half lives and Pn Digital data acquisition system features Analysis procedure (Preliminary plots / ongoing) ID plot evolution in the analysis AnalysisBELENIntroductionExperiment Analysis

Tracking detectors calibrations & particle ID Particle ID check via 205 Bi isomers, 216 Po α-decays SIMBA calibration implantation patterns Analysis of half lives and Pn Digital data acquisition system features 205 Bi setting has been used as Z identification reference via isomer gamma rays and 216 Po setting as A/Q checking in the region of interest. Analysis procedure (Preliminary plots / ongoing) A/Q Z 205Bi keV Counts AnalysisBELENIntroductionExperiment Analysis

Tracking detectors calibrations & particle ID Particle ID check via 205 Bi isomers, 216 Po α-decays SIMBA calibration implantation patterns Analysis of half lives and Pn Digital data acquisition system features Implants keV Ch Beta disintegrations -SIMBA c alibrations are being performed with a 137 Cs source And alpha lines from a 216Po setting - β - decay curves will provide half lives values Implantation Counts Energy deposited (ch) Noise Beta decay Analysis procedure (Preliminary plots / ongoing) AnalysisBELENIntroductionExperiment Analysis

-Time correlation between neutron and beta decay Cf for BELEN efficiency and can be checked with 135 Sb Tracking detectors calibrations & particle ID Particle ID check via 205 Bi isomers, 216 Po α-decays SIMBA calibration implantation patterns Analysis of half lives and Pn Digital data acquisition system features Pulser Noise Neutron signal Counts Energy (ch) Analysis procedure (Preliminary plots / ongoing) First estimation of 210Po halflife of 150 ms. Compatible with literatur results AnalysisBELENIntroductionExperiment Analysis

DDAS -Triggerless digital data acquisition system used for the first time in this type of experiments at GSI. -It allows to eliminate the dead time of conventional acquisition systems thanks to the double memory digital cards which allow to acquire data and reading of previously taken data at the same time. -Advantages: 1.Increase the efficiency by about 8% (from 27 to 35%) 2.Flexibility for large time correlation (fundamental to obtain correlations with all neutron and to change the gates offline) 3.Allows to correct some experimental effects, e.g. To reduce neutron background from uncorrelated neutrons. Tracking detectors calibrations & particle ID Particle ID check via 205 Bi isomers, 216 Po α-decays SIMBA calibration implantation patterns Analysis of half lives and Pn Digital data acquisition system features Analysis procedure (Preliminary plots / ongoing) AnalysisBELENIntroductionExperiment Analysis

Future analysis work  Improved ID-Plot via final calibrations of frs detectors  Determine implantation rates for each identified isotope  Determine implant-beta correlations and neutron-beta correlations  Implement an analysis method for deriving half-lifes and for determining beta-delayed neutron emission probabilities.  In collaboration with theoreticians, study the impact of these results on nuclear models, as well as on r-process nucleosynthesis calculations. AnalysisBELENIntroductionExperiment Analysis

Design of the prototype of the BELEN detector with MCNPX and GEANT4 simulations. Different versions: AnalysisFuture goalsIntroductionExperiment BELEN Tests and experiments with Beta dELayEd Neutron detector (BELEN) Background measurements at GSI and Canfranc underground laboratory. BELEN-20 (20atm) for JYFL. Experiments at JYFLTRAP (Finland). Measurements of β delayed neutron emission of fission fragments (UPC, IFIC, CIEMAT): Nov 2009: 95 Rb, 88 Br, 94 Rb, 138 I. (cal. and nucl. Structure) Jun 2010 : 95 Rb, 88 Br, 85 As, 86 As, 85 Ge, 91 Br, 137 I.(decay heat and testing models) BELEN-30 (20 (20atm), 10 (10 atm)) for FRS-GSI. Two experiments at GSI with & SIMBA September 2011, nuclei of astrophysical interest: S323: 127 Pd, 126 Pd, 128 AgS410: 215 Tl, 211 Hg

Future goals for the UPC Beta dELayEd Neutron detector (BELEN) AnalysisFuture goalsIntroductionExperiment BELEN  Initial plans were for 44 3 He counters. Now collaboration with GSI & JINR (Dubna) Plans of new design with 90 counters (detection efficiency ~70%) atm UPC (refurbishment) atm GSI 40 4 atm JINR  Combine with Advanced Implantation Detector Array (AIDA), Surrey, UK.  Optimize detection system (BELEN) and its acquisition (DDAS) for future experiments with more exotic beams (FAIR).  Prepare for first experiments closer to the r-process (>2018)  Measure P xn  New experiment at JYFL (Finland) on 2013  New proposals for RIKEN RIB facility in Japan COUNTERS FOR BEta deLayEd Neutron detector

The end! Institut de Física Corpuscular de València (IFIC) Universitat Politècnica de Catalunya (UPC) Helmholtzzentrum für Schwerionenforschung GmbH (GSI) NSCL, Michigan State University (MSU-USA) CIEMAT (Madrid) Universidade de Santigo de Compostela (USC) Department of Physics, University of Surrey (UK) CFNUL Universidade de Lisboa (Portugal) School of Physics & Astronomy, U. Edinburgh (UK) Department of Physics, University of Liverpool (UK) STFC, Daresbury Laboratory (UK) Laboratori Nazionali di Legnaro, INFN (Italy) Flerov Laboratory, JINR, Dubna (Russia) CENBG, Université Bordeaux (France) Thanks to A.Algora, Y.Litvinov and K.Smith for some slides

Tomorrow!

State of the art FRDM + QRPA K.-L. Kratz, (private communication) r-process path T 1/2 PnPn Exp. T. Kurtukian et al. Phys. Lett. B (Submitted) DF3 + QRPA+ FRDM + QRPA (P.Moeller, et al. 2003) (I.Borzov, et al. 2003) Effect of half-lives The Astr. Jour., 579 (2002), H. Schatz et al. Proc. CGS-13 (2009), G. Martinez-Pinedo K.-L. Kratz, (private communication)