PSI-2 - the pilot experiment of the JULE-PSI project

1. PSI-2 - the pilot experiment of the JULE-PSI project Arkadi Kreter on behalf of FZJ PWI team Institute for Energy and Climate Research - Plasma Physics, Forschungszentrum Jülich, Association EURATOM-FZJ, Trilateral Euregio Cluster, Germany 2nd International Workshop on Plasma Material Interaction Facilities for Fusion Research (PMIF) Jülich, Germany, 19 September 2011

2. JULE-PSI: Jülich Linear Experiment for PSI studies in a Hot Cell • PMI studies with • Neutron irradiated materials • All wall materials incl. Beryllium • Low quantities of Tritium Based on PSI-2 / PISCES type device Installation in a Hot Cell for handling of radioactive and toxic materials Schematic view Plasma source Target chamber Surface analysis Linear manipulator  Talk by B. Unterberg PSI-2 is the pilot experiment of the JULE-PSI project

3. PSI-1/2: 17 years of operation in Berlin • Formerly operated by IPP-Garching at Humboldt Univ., Berlin • PSI-1 was first operated in 1992 • Upgrade to PSI-2 in 1998: extended target chamber with 2 additional coils • Transfer to FZJ in October 2009 PSI-2 installation in Berlin 1 m

4. PSI-2: new life in Jülich • Transferred from Berlin to Jülich in October 2009 • First plasma in Jülich in January 2011 • Idea: Existing PSI-2 as the pilot experiment of the JULE-PSI project, outside of hot cell • Name: PSI-2 (Jülich) • Goals: • Gain experience operating linear plasma device • Test of components for JULE-PSI • Prototype of target station • Plasma source optimization • Diagnostics • Other peripheral components • Contribute to current PMI research topics

5. Current installation of PSI-2 Current status corresponds to the installation in Berlin before transport

6. First plasma of PSI-2 in Jülich Text from IEK-4 news web site of 7/Jan/2011 First plasma in PSI-2 Jülich Today, Friday 7th of January 2011, 6.30 pm, the very first Argon discharge has been produced in the PSI-2 Jülich device. This achievement constitutes a major milestone for our PSI programme on linear devices, which aims at the investigation of PSI processes with neutron activated fusion materials with the linear plasma device JULE-PSI in the Hot Material Laboratory (HML) of FZJ. PSI-2 Jülich will serve as a pilot experiment for this development and supplement our portfolio of facilities for the joint TEC programme on plasma-surface interactions. Many thanks to the whole PSI-2 team, in particular to our colleagues from Berlin, Werner Bohmeyer and Achim Mans. Since August 2011 routine operation in deuterium

7. Typical plasma parameters in PSI-2 For deuterium plasma Example of Ar plasma profile at target position

8. PSI-2: plasma generator with cylindrical cathode Cylindrical cathode w/o heat shield • Arc discharge up to 1000 A and 150 V • Typical regime of operation: • Heating up and cooling down ~60 min • Steady-state plasma of several hours per day • Change of discharge parameters (incl. working gas) on one day possible • Exchange of the cathode every 12 – 18 months • Advantages: • Larger emitter area  more efficient plasma production • Less prone to break due to thermal stresses • Observation through the aperture • Drawback (decisive): • Hollow plasma profile Cylindrical cathode assembly

9. PSI-2: new disc-shaped cathode • Originally designed by H. Greuner • Partially constructed and tested in Berlin, but never in plasma operation • Currently: optimization of design and testing • Installation on PSI-2 is planned for Dec. 2011 Heater of disc-shaped cathode Disc-shaped cathode assembly

10. Plasma source options for JULE-PSI • Options to optimize arc source performance / reliability are analysed in collaboration with the Budker Institute  talk by A. Ivanov (for V. Davydenko) • Alternatively, helicon-type plasma source is considered, also in collaboration with the Budker Institute • Synergy from the helicon source development at ORNL?

11. Target manipulators • First stage: side-fed manipulator from Berlin • Currently being refurbished and adapted for our purposes • To be installed in Oct 2011 • Second stage: new target station PSI-2 current installation Layout of sample holder in plasma Side-fed manipulator support structure

12. Target station Plasma source Typical target position Exchange and Analysis chamber Target manipulator • Serves as prototype of JULE-PSI target station  talk by B. Unterberg • Currently being manufactured • Installation by the end of 2011

13. Diagnostics on PSI-2 PSI-2 serves as test-bed for diagnostic development for JULE-PSI  Focus on reliability and easy maintenance Plasma diagnostics (characterization of background plasma) • Optical spectroscopy • Langmuir probe • Thomson scattering being considered as substitute of Langmuir probe In-situ PMI diagnostics • Optical spectroscopy • IR thermography • Quartz microbalance (QMB) In-vacuo sample analysis • Target station: linear manipulator and surface analysis station with • Laser-aided analysis methods (LID, LIBS) talk by B. Unterberg • Glow discharge spectroscopy talk by C. Klepper

14. Spectroscopy Spectrometer systems available: i) Direct imaging spectrometer at the target Spectrometer Acton 0.75m (SP2750 UV-VIS-NIR) with detector 2D EMCCD Andor NEWTON DU971 1600 x 400 ii) Fibre-coupled spectrometer in Littrow arrangement (10 nm coverage @ R=20000) Spectrometer 0.75 m Echelle optimised for VIS with detector 2D EMCCD Andor IXON DU888 EC 1024 x 1024 iii) Fibre-coupled spectrometer in Littrow arrangement (2 nm coverage @ R=100000) Spectrometer 1.25 m Echelle optimised for VIS with detector 2D EMCCD Andor IXON DU888 EC 1024 x 1024 iv) 2 sets of 4 channel compact spectrometers (300-858 nm @ R= 7500) Avantes set (JET KT1-type with 1800 l/mm and 10 m slit): Ch.1 300-455 nm, ch.2 450-577 nm, ch.3 575-681 nm, ch.4 658-858 nm v) Overview compact spectrometer Avantes 300 -1100 nm with 300 l/mm and 10 m slit vi) Spectrelle and deep UV compact spectrometer to be shared with TEXTOR

15. Ex-situ surface analysis available in FZJ • High-precision balance (0.1 g) • Weight loss measurements • Thermal desorption spectrometry (TDS) • Retention with temperature resolution • SEM / EDX • Morphology / Elemental composition • Ion beam analyses: NRA, RBS,.. • Absolute amounts of surface materials, limited depth resolution • Secondary Ion Mass Spectrometry (SIMS) • Depth distribution of elements • X-ray Photoelectron Spectrometry (XPS) • Chemical composition and state (e.g. carbidization)

16. Physics programme on PSI-2 Recombining deuterium plasma • Plasma characterization • Hydrogen and impurity spectroscopy • Fuel retention in tungsten and graphite under the influence of impurities • Erosion of tungsten and tungsten spectroscopy • Simulation of transient heat loads by laser (collaboration with Budker Institute) • Talks by A. Burdakov and A. Shoshin • EUROFER as first wall material Neutralizer plate

17. Summary • PSI-2 to serve as pilot experiment for JULE-PSI • Transferred from Berlin to Jülich and successfully taken into operation • New components (cathode, target station, laser, diagnostics) purchased and partially delivered and commissioned • Physics programme started with plasma characterization and spectroscopic studies • PMI programme to start from October 2011