1. BL1U at TRIUMF UCN Beamline Spallation Target & Remote-Handling System (Aug/2010) L.Lee

2. Concept for Spallation Target & Remote-Handling System 300 K D 2 O Flask w/ Pb+steel wall graphite W target Cooling block Driveshaft Retractable Target with its own “In-situ” Shielded Flask Three modes:(a) Production mode  Target in beam (b) UCN Service mode  Target retracted (service cryostat or beamline) (c) Target-change mode  Target retracted & flask movable

3. (Removable) Driveshaft for Target motion (w/ self-locating clutch) Valve 300 K D 2 O Moderator near this region Beam Flexible shaft/cable (STOW) for shutters Water-cooled Collar/Ring (Tapered) Heat Sink (Tapered) Rack & Pinion system Rail & Bearings Lead Cask/Pig Spallation Target System ( *Note: Wall thickness of Target Flask/Pig not yet optimized ) Mount Target Water lines (Concept/Layout after consultation with Target & Remote-Handling experts)

4. Valve Beam Lead Cask/Pig Target in primary “Operation” position Target 300 K D 2 O tank 20 K D 2 O cryostat Tungsten Spallation target 40  A proton beam: - ON for 60 sec - OFF for 180 sec Common Vacuum between Beamline & Target

5. Valve Lead Cask/Pig Target Beam OFF Target Cooling period Retract Target into Cask Driveshaft for Target motion Target in Retracted position 300 K D 2 O tank 20 K D 2 O cryostat

6. Valve Lead Cask/Pig Target Ready for Servicing of UCN Source & Cryostats (Permissible Dose Rates for servicing UCN source? Thickness of Pb layer inside Cask/Pig?  Joe M.) Target Retracted & Shutters closed 300 K D 2 O tank 20 K D 2 O cryostat

7. Lead Cask/Pig Target Disassembly for Target and Flask extraction Driveshaft for Target motion 300 K D 2 O tank 20 K D 2 O cryostat

8. Lead Cask/Pig Target 300 K D 2 O tank 20 K D 2 O cryostat Disassembly for Target and Flask extraction

9. Lead Cask/Pig Target Relocate Target & Flask to External Flask External Transport Flask 300 K D 2 O tank 20 K D 2 O cryostat

10. 300K D 2 O W Target Cooling Block (Al,Cu, or W) Carriage/Mount Tapered Coupler (Al,Cu, or W) Al Beampipe Flask (steel/Pb) Spallation Target Layout

11. W Target 300K D 2 O Spallation Target Layout (Zoom-In)

12. 300K D 2 O W Target Carriage/Mount Tapered Coupler (Al,Cu, or W) Spallation Target Layout (Zoom-In)

13. 300K D 2 O W Target Carriage/MountCooling Block (Al,Cu, or W) Spallation Target Layout (Zoom-In) Tapered Coupler (Al,Cu, or W)

14. 300K D 2 O W Target Carriage/Mount Al Beampipe Spallation Target Layout (Zoom-In) Tapered Coupler (Al,Cu, or W) Cooling Block (Al,Cu, or W)

15. Spallation Target: Retracted by 4 cm 300K D 2 O

16. W Target Carriage/Mount Al Beampipe Alternate Geometries (to increase cooling) Tapered Coupler (Al,Cu, or W) Cooling Block (Al,Cu, or W) Increase surface contact with target

17. Spallation Target Thermal Analysis Thermal Analysis in finite-element code (ALGOR, Tom R.)  Temperature distribution, Max/Saturation temperatures, Thermal stresses,… 480 MeV proton beam @ 40  A (60 sec ON, 180 sec OFF) Assume full beam power dissipated within Tungsten target Initial setup: Simplified model of Tungsten target and Aluminum cooling block Tungsten cylinder “perfectly” coupled to Aluminum cylinder Downstream surface of Aluminum block held at 10°C Radiative cooling at Tungsten target surface  Blackbody to “open” 21°C environment  Emissivity ~ 0.2 TungstenAluminumCopperTitanium  4.5  10 –6 /°C23  10 –6 /°C16.5  10 –6 /°C8.6  10 –6 /°C  173 Wm –1K –1 237 Wm –1K –1 401 Wm –1K –1 22 Wm –1K –1 T melt 3422 °C660 °C1084 °C1668 °C

18. UCN Beam & Target Parameters for ALGOR Analysis  4 cm  6.5 cm 12 cm 4 cm Tungsten Target Al Cooling Block (Water-cooled, @ 10°C ) Proton Beam (Red) Uniform cylinder,  1 cm Stops in Tungsten target Power deposition (see graph) CYCLE:Beam ON (40  A) for 60s Beam OFF (0  A) for 180s Al block

19. dE/dx Profile in Tungsten for ALGOR Analysis

20. Thermal Analysis Preliminary Results

22. Spallation Target Issues Thermal Analysis: Aluminum gets too close to its melting point  Use Cu instead (?) Saturation (Maximum) Temperature Thermal Stresses Water Flow rate  Hatanaka-san has estimated ~10 L/min for (  T) water ~ 30 K Radiative Cooling  Include Aluminum beampipe More realistic model  Target Geometry, Thermal coupling Failure modes/Safety  120  A on target for an “extended” period Target & Remote-Handling Conceptual Design: Permissible radiation dose levels around cryostat Thickness of Pb-lining for the In-Situ Flask/Cask  overall geometry & mass Mechanical issues (many) Services (water and air) Amount of Aluminum around spallation target  how much can be tolerated (MCNPX) Impact on Graphite Reflector design Integration Issues (with UCN Source)