1 / 13

DIONISOS: Upgrading to the high temperature regime

DIONISOS: Upgrading to the high temperature regime. G.M. Wright , K. Woller, R. Sullivan, H. Barnard, P. Stahle, D.G. Whyte Plasma Science & Fusion Center, MIT, Cambridge USA. Outline. DIONISOS Advantages and capabilities The high temperature regime Importance Details on upgrades

jalen
Download Presentation

DIONISOS: Upgrading to the high temperature regime

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. DIONISOS: Upgrading to the high temperature regime G.M. Wright, K. Woller, R. Sullivan, H. Barnard, P. Stahle, D.G. Whyte Plasma Science & Fusion Center, MIT, Cambridge USA

  2. Outline • DIONISOS • Advantages and capabilities • The high temperature regime • Importance • Details on upgrades • He concentrations and depth profiles in W fuzz layers • Heavy ion ERD analysis

  3. DIONISOS has similar capabilities to other linear plasma devices in the US

  4. What makes DIONISOS unique? • Simultaneous plasma and ion beam exposure of targets • Active target heating and cooling (Ttarget = 300-750 K) • In-situ, time-resolved ion beam analysis • In-situ target irradiation by high-energy (~MeV) ions for irradiated materials studies.

  5. Why are we interested in the high temperature regime for DIONISOS? • Commercial fusion reactors will run with “hot walls” (e.g. 900-1000 K) • New physics and surface effects at high temperature. W nanostructure Bubbles Baldwin et al, JNM 390-391 Ueda, DIV-SOL ITPA, Amsterdam, May 2009 • Also allows for in-situ target thermal desorption spectroscopy and annealing.

  6. A new target holder is required to reach these temperatures in DIONISOS • Heatwave Labs UHV substrate heater with DC power supply • Max operating temperature of 1473 K • Electrically isolated from target • Mo heat shielding on the sides and back • Active PID temperature control (K-type thermocouple) Substrate heater Isolated sample clips for target biassing Heat shielding Power leads

  7. Some key differences between the current target holder and the high-T target holder • Operating range RT-750 K • Active cooling and heating • Large targets (> plasma column) Current target holder High-T target holder • Operating range 200-750 K • Active heating feedback • Small targets (< plasma column)

  8. Other components must also be protected from the additional radiative heating from the target • Hot target leads to radiative heating of sensitive components. • Solid-state detectors used for IBA are cooled through thermal contact with a water-cooled plate. Cooling line Heat sink Detector Detector housing Support rod

  9. Ion beam analysis on W nano-filament formation has yielded useful new data • Fuzz grown in Pilot-PSI with peaked flux and temperature profile. • ERD performed with 7 MeV O4+ ions for He detection. • Beam spot is 2.0 x 3.5 mm (oval) • Fuzz layer is only 5-10 % density of bulk tungsten. • Penetration depth of 7 MeV O4+ ions is ~950 nm Center 2mm 4mm 6mm 8mm 10mm

  10. W Fuzz has been grown under a variety of conditions Grown in Pilot-PSI with peaked flux and temperature profile. G. De Temmerman, FOM Rijnhuizen, The Netherlands NOT exposure conditions for fuzz growth, just an example of possible gradients in Pilot-PSI exposures. PISCES targets have uniform conditions across the surface.

  11. Radial scan on W13 demonstrates transition from fuzz to non-fuzz conditions • He is distributed uniformly throughout the fuzz layer. • Before fuzz formation, He is peaked at the surface. • All other targets had flat He profiles similar to the center of W13 He concentration (at. %)

  12. Comparison of He concentrations from all other targets • He concentration in the W fuzz falls within 0.5-1.0 at.% for all conditions investigated here. • No clear dependence of He concentration on He fluence or surface temperature. • More data needed. Controlled parameter scans could reveal hidden dependences.

  13. Future goals • Further investigations into the dynamics of PSI and PSI for irradiated materials • In-situ fuzz growth in Pilot-PSI • Time-resolved ERD measurements of W fuzz growth • Retention in high-temperature walls under irradiation conditions • Characterization of carbon deposition on high-temperature tungsten substrate

More Related