1. All Metal Gate Valve from VAT
Tug Arkan
December 12, 2014

3. Cleanliness for particle free UHV standard
VAT:
Cleaned to ISO6 (Class 1000) standards at the vendor
Closed during shipping
Flanges are covered with some kind of cover plates
Double bagged in the cleanroom
CAF Cleanroom Group:
Move the valve from production floor to Class 10 (ISO 4) cleanroom
Clean the valve to Class 10 (ISO4) standard by blowing with ionized nitrogen and monitoring with a particle counter before assembly

4. Copper plated inside for the inner workings of the valve mechanism
(not special RF liner)
Gate valve fully open in its holder fixture at the cleanroom

5. Upstream end gate valve (CM2)
For LCLS-II prototype cavities there will be a spacer flange assembled between the gate valve and cavity flange

6. Downstream end gate valve (CM2)
CM2: Magnet + BPM + Spool piece + Downstream end gate valve
LCLS2: BPM + Magnet Spool Piece + Downstream end gate valve

7. LCLS-II prototype module cavity string

8. 3.9GHz cavity string
Zero length reducer: from NW78 to NW40 aluminum diamond seal

9. Upstream end gate valve cold mass interface
A titanium gate valve holder is tack welded to the helium vessel body of Cav#1
This holder is used to ensure that the weight of the gate valve (~50 lbs) doesn’t disturb the RF properties of the Cav#1

10. Downstream end gate valve cold mass interface
Gate valves are inside the 5K shield attached to the Cav#1 and magnet spool piece for LCLS-II. No external thermal intercepts for the valves.

11. LCLS-II Gate Valves from VAT
Cleaned to Class 1000 standards and double bagged
Magnetic permeability class 1 (µr ≤ 1.05)
Flanges are made of 316L
DESY required thermal degasification at 950°C for the valve body and the bonnet but not the mechanism components of valve 472XX-XE01-ADD1. Same for LCLS-II

12. Quality Control & Acceptance
This valve is shipped double bagged and cleaned to ISO6 standards from VAT.
We will open the bags and move the VAT valve to ISO4 cleanroom
Visual check, open the flange covers and inspect for scratches and nicks
Follow the opening and cleaning procedure of the valve and record the particle counts
Follow the travelers to ensure that the stainless steel assembly hardware is assembled properly during string assembly to eliminate galling potentials