Students'coffee - 16th meeting Nanostructured target materials for intense secondary beam production at CERN-ISOLDE João Pedro Ramos 11 th of March 2013 T. Stora, A. M. R. Senos, P. Bowen A. Gottberg, T. M. Mendonça, C. Seiffert

Jo João Pedro Ramos Students'coffee - 16th meeting Nanostructured target materials for intense secondary beam production at CERN-ISOLDE Table of Contents 2/25  Introduction  ISOLDE  Beam production  Target materials  Nanostructured calcium oxide target  Ti-based refractory target materials  Uranium carbide target developments

Jo João Pedro Ramos Students'coffee - 16th meeting Nanostructured target materials for intense secondary beam production at CERN-ISOLDE Introduction Basic concepts 4/25 Introduction

Jo João Pedro Ramos Students'coffee - 16th meeting Nanostructured target materials for intense secondary beam production at CERN-ISOLDE ISOLDE Facility at CERN 4/25 (Isotope Separator OnLine DEvice)  1000 Isotopes available  Z=2 to 92  73 chemical elements  to ions/s  30 targets per year  300 to 400 8h shifts per year  30-40% of all CERN protons  Beams up to several MeV/u Introduction

Jo João Pedro Ramos Students'coffee - 16th meeting Nanostructured target materials for intense secondary beam production at CERN-ISOLDE ISOLDE Facility at CERN CERN. CERN in a nutshell. (accessed August 13, 2011). 5/25 Introduction

Jo João Pedro Ramos Students'coffee - 16th meeting Nanostructured target materials for intense secondary beam production at CERN-ISOLDE Container Transfer Line Ion Source ISOLDE Facility at CERN 6/25 Köster, U. Intense Radioactive-Ion Beams Produced with the ISOL Method. The European Physical Journal A 2002, 15, Target unit pictures courtesy of Stefano Marzari. Introduction

Jo João Pedro Ramos Students'coffee - 16th meeting Nanostructured target materials for intense secondary beam production at CERN-ISOLDE RIB Production 7/25 Protons +/- 8V 500A +/- 9V 1000A 4. Ionization 3. Effusion 2. Diffusion 1. Production (Nuclear Reactions) Target Material – g/cm 2 “Oven” (Ta,Mo,Nb,C) Ion Source Transfer Line (Ta, Mo, SiO 2 ) * Introduction

Jo João Pedro Ramos Students'coffee - 16th meeting Nanostructured target materials for intense secondary beam production at CERN-ISOLDE RIB Production 8/25 Production Diffusion Effusion Ionization  Nuclear reactions  Thermalization  Out of the material grains  Through porosity  Transfer line Proton flux Cross-section Nr. exposed atoms Ionization  Surface Ionization  Elements with low ionization potential  Plasma Ionization  Very efficient but not selective  Laser Ionization  Selective metallic elements ionization. Introduction Transfer lines  Element Selection  Condensation

Jo João Pedro Ramos Students'coffee - 16th meeting Nanostructured target materials for intense secondary beam production at CERN-ISOLDE  Oxides, carbides, metals or molten salts  Powders, pellets or liquid form  Material characteristics  High production cross section  Stability at high temperatures  Resistance to radiation damage Microstructural characteristics:  Nanometric grain size  High porosity (>30%)  Macroporosity (>100nm) Target Materials 9/25 Improved effusion and mainly diffusion of alkali, alkali-earth and noble gases Diffusion usually limits the release Fernandes, S. Submicro- and Nanostructured Porous Materials for Productin of High-Intensity Exotic Radioactive Ion Beams; PhD Thesis; École Polytechnique Fédérale de Lausanne: Lausanne, Uranium carbide pictures courtesy of Alexander Gottberg Nanometric CaO powder target Al 2 O 3 - SEM Introduction

Jo João Pedro Ramos Students'coffee - 16th meeting Nanostructured target materials for intense secondary beam production at CERN-ISOLDE Nanostructured CaO Master thesis subject CERN – T. Stora University of Aveiro – A.M.R. Senos 10/25 CaO

Jo João Pedro Ramos Students'coffee - 16th meeting Nanostructured target materials for intense secondary beam production at CERN-ISOLDE Motivation  Main issues:  Unstable yields  Low since the beginning  Drop over time Turrion, M.; Urszula, H.-I. ISOLDE Yield Database. (accessed December 1st, 2011) Shift numbers by courtesy of Magdalena Kowalska, Physics Coordinator at ISOLDE, CERN. CaO 11/25 1 to 2 targets built every year Shifts from 2006 to 2011 Microstructure related Material study needed!

Jo João Pedro Ramos Students'coffee - 16th meeting Nanostructured target materials for intense secondary beam production at CERN-ISOLDE Calcium Oxide Production CaO 12/25 Sintering studies show net sintering effects after T>1000 o C

Jo João Pedro Ramos Students'coffee - 16th meeting Nanostructured target materials for intense secondary beam production at CERN-ISOLDE Target Production “Old procedure”  ~14µm 99% pure CaCO 3  up to 1200ºC  No heating/cooling rates  Holding time not defined  to Pa  No cares taken about CaO exposure to air “New procedure”  >5µm 99.5% pure CaCO 3  800 o C  10 o C/min  ~48h  Pa to 160Pa 13/25 CaO CaO#469 Produced

Jo João Pedro Ramos Students'coffee - 16th meeting Nanostructured target materials for intense secondary beam production at CERN-ISOLDE Target Operation 14/25 Old settings  T up to 1200 o C  3x10 13 ppp CaO Initial m 2 /g nm 33% porosity (~11nm) Final (48h) ~4 m 2 /g  m 9% porosity (~9nm) New settings  T up to 800 o C  8x10 12 ppp Initial >40 m 2 /g <45nm 47% porosity (~20nm) Final (48h) >38m 2 /g <45nm 47% porosity (~20nm) Temperature effect only! Avoid Microstructure Degradation

Jo João Pedro Ramos Students'coffee - 16th meeting Nanostructured target materials for intense secondary beam production at CERN-ISOLDE Online Results CaO 15/25

Jo João Pedro Ramos Students'coffee - 16th meeting Nanostructured target materials for intense secondary beam production at CERN-ISOLDE Ti-based refractory materials PhD subject CERN – T. Stora EPFL – Paul Bowen University of Aveiro – A.M.R. Senos 16/25 Ti-based

Jo João Pedro Ramos Students'coffee - 16th meeting Nanostructured target materials for intense secondary beam production at CERN-ISOLDE Raw MaterialsPressingSintering Sample Porosity (20 – 40%) Characterization: Scanning Electron Microscopy X-ray Diffraction N 2 Adsorption Up to 1450 o C TiC and TiO 2 Material Development 17/25 Ti-based

Jo João Pedro Ramos Students'coffee - 16th meeting Nanostructured target materials for intense secondary beam production at CERN-ISOLDE Proton IrradiationsGamma spectroscopy Heating Cycle RaBIT First annealing heals defects caused by protons TiC and TiO 2 Material Development Ca not enough statistics 18/25 Ti-based

Jo João Pedro Ramos Students'coffee - 16th meeting Nanostructured target materials for intense secondary beam production at CERN-ISOLDE Draft Program  Year 2013:  Nanometric material synthesis studies with different techniques (core shell material)  Sintering studies  Further investigation and development of the effusion/diffusion model proposed by Bouquerel  Year 2014:  Further material studies  Online target testing (exotic beams of K and Ca) 19/25 PhD

Jo João Pedro Ramos Students'coffee - 16th meeting Nanostructured target materials for intense secondary beam production at CERN-ISOLDE Uranium carbide nanomaterial development Project of Alexander Gottberg ActILab Collaboration 20/25 Uranium Carbide

Jo João Pedro Ramos Students'coffee - 16th meeting Nanostructured target materials for intense secondary beam production at CERN-ISOLDE Target Material Distribution Actinide targets at ISOLDE in 2011 (2010) 249 shifts out of 396  68% of total (72%) 13 new units (12 new, 2 old) Uranium Carbide 21/25 Slide, courtesy of Alexander Gottberg

Jo João Pedro Ramos Students'coffee - 16th meeting Nanostructured target materials for intense secondary beam production at CERN-ISOLDE UO 2 + 6C → UC 2 + 2C + 2CO (g) Production Process: 1.Blending UO 2 and C powder 2.Cold pressing into pills 3.Carbothermic reduction of UO 2 two orders of magnitude Development towards highly porous, nano-tailored matrixes: 1.Grinding UO 2 2.Grinding UC 2 3.New synthesis approaches (sol-gel) Uranium Carbide UC material Synthesis / Development In House 22/25 Slide, courtesy of Alexander Gottberg

Jo João Pedro Ramos Students'coffee - 16th meeting Nanostructured target materials for intense secondary beam production at CERN-ISOLDE µ-spot X-ray fluorescence mapping Uranium Gallium Micro Spot Material Mapping at SLS SEM Uranium 20µm UC 2 reflex 1 µ-spot X-ray diffraction UC 2 reflex 3 Uranium Carbide 23/25 Slide, courtesy of Alexander Gottberg

Jo João Pedro Ramos Students'coffee - 16th meeting Nanostructured target materials for intense secondary beam production at CERN-ISOLDE Preliminary Online Results Despites the difficulties: 11 Be: 5.3x10 7 1/µC, database: 7x10 6 1/µC Record yields for Cs Structure seems widely conserved over time and temperature Uranium Carbide 24/25 Slide, courtesy of Alexander Gottberg

Jo João Pedro Ramos Students'coffee - 16th meeting Nanostructured target materials for intense secondary beam production at CERN-ISOLDE Thank you! Comments and questions? 25/25