Activities

• We have a number of 5-inch PMTs and acrylic couplers salvaged from Palo Verde. Six PMTs will end up installed in acrylic boxes sealed to 8-inch vacuum flanges on the M5 calibration chimney.
  
  

Drawings and plots

• Engineer's drawings of the M5 flange (from Berkeley): M5A flange (PDF); see also Z-axis assy on M5A flange (PDF).
• Geant4 drawings of the chimney region: (GIF) or (PS)
• Geant4 results for light collected versus Z position of a 1 MeV electron on the Z axis: (GIF) or (PS)

Update

• This page contains the latest design for the 5-inch PMTs:
• They will be installed in the six 8-inch ports on the M5A flange M5A flange (PDF);
• Since the Radon emanation from the six 5-inch PMTs is estimated to be 15 times the limit of 1uBq/m^3, as specified in the US-proposal, an enclosure is needed.
• As shown here,
  
  
  
  ((PS) or (GIF)) the enclosure is made of stainless steel (green, dark blue), specialty uv-transmitting (suvt) acrylic (magenta) and teflon gaskets (light blue).
• A stainless steel (304L) cylinder is welded onto an 8-inch conflat flange (green). It will fit into the 8-inch opening of the M5A flange (dark blue). Endcaps (magenta), made from uv-transmitting acrylic, fit the surface of the photocathodes. The endcaps are held in place by stops at the bottom of the stainless cylinders. They are sealed by a sandwich consisting of a teflon gasket (light blue), a flat disk made from suvt acrylic (magenta) and a stainless steel ring (green). It is held together by 12 stainless screws.
  
  
• Here are some photos of the 5-inch PMT enclosure:
  • The test setup. The 5-inch PMT enclosure is inside this test container. The 8-inch conflat flange is on the right hand side, the N2 gas inlet and outlet to the left.
  • Two pictures, picture 1 and picture 2, of the 5-inch PMT enclosure.
  • The test container (left) and the 5-inch PMT enclosure (right).
  • The seal, a sandwich consisting of a teflon gasket, a flat disk made from suvt acrylic and a stainless steel ring. It is held together by 12 stainless screws.
  • A look into the test setup through the suvt acrylic window. Inside the liquid scintillator and the N2 gas outlet tube can be seen.
  
  
• A prototype 5-inch PMT enclosure has been tested in a test container (as shown above) since 4/20/01. The test container is filled with liquid scintillator (40%PC) at 1.2 atm N2 and ~26C. So far no signs of aging and/or crazing can be observed.
• Contact G. Horton-Smith. or Johannes Ritter for further details.