1. CTF Users’ Perspective
E. Daly, K. Davis
12 December 2018

2. Proposals for Expanding Capacity Summary
Outline
UITF
Introduction
Performance
Proposals for Expanding Capacity
Summary
VTA
Plan view of Test Lab showing UITF/ CMTF / VTA
12 December 2018

3. Introduction
New uses for UITF are being considered, some requiring cryogenics
Current cryo users include VTA for SRF Ops and R&D, CMTF cryomodule testing, UITF ¼ CM testing/operations and HDIce
Capacity is currently over-subscribed
It will be a challenge (impossible?) to operate the existing programs simultaneously
How could we boost capacity of CTF in order to operate UITF, CMTF and VTA?
Cryo group has been improving the CTF over several years
Some things have already been done (UIM, Cold Box 3)
Some are in the works (Recovery, Purification)
12 December 2018

4. Current Performance - Liquefaction
CTF is primarily used as a supply of LHe in support of cavity vertical testing
Liquefaction load filling dewars
10 kL dewar holds inventory
Cold Box 3 – increased liquefaction capability significantly
10 kL dewar fills at > 2%/hr (2X improvement)
Current capacity easily suits needs for independent VTA operations
8 dewars (capacity range ~200 to 2000 liters)
12 December 2018

5. Current Performance - Refrigeration
CTF is also used for refrigeration when pumping VTA dewars to 2K and operating CMTF
Refrigeration at “2K”
Use Kinney pumps to lower pressure below atm (Recovery System)
VTA uses Pair Pumps to achieve lower pressures
CMTF uses Kinney pumps in a closed cycle refrigeration mode
With a CM in CMTF on-line, make up rate to 10 kL dewar is reduced
Depends on CM heat load (e.g. ~0.5% reduction with LCLS-II CM)
Impacts ability to fill dewars
With a CM in CMTF on-line, Recovery System is shared
Impacts ability to pump VTA dewars while maintaining stable pressure in CM
12 December 2018

6. Recovery System – Vacuum/Storage & Purification
Purifiers remove contaminants added during operations
Current CTF down involves commissioning additional purifier
Cryo can provide details on capacity improvement
Vacuum system recovers helium (atmospheric and sub-atmospheric
Current CTF down – installation of refurbished Kinney pump and piping
Cryo can provide details on capacity improvement
12 December 2018

7. 2014 CMTF on-line / off-line
Dewar make up rate was insufficient to support VTA & CMTF operations
12 December 2018

8. 2018 CMTF on-line / off-line
Note that CM cooldown reduces make up rate further over multi-day period
No CM in CMTF (2.5%/hr)
CM-10 on-line (2.0%/hr)
12 December 2018

9. Multi-User Cryo Estimates
Estimate from 2016 includes Hall B, so updated is needed
Format is reasonable so we can continue to use as-is
Concluded that only two of four loads can be run simultaneously
12 December 2018

10. Comments on Cost
Coordination with Cryo Group is needed to understand full costs including design, procurement, installation and commissioning AND impact on other subsystems
Recent examples of component procurements
LCLS-II Heat Exchanger - $275K
LERF Cryo Can - $271K
Replacement Pair Pump - $60K
12 December 2018

11. Some Proposals
Increase recovery capacity to match upgraded cold box supply capacity
Cryo is working on this currently
What is expected performance when completed?
Ability to supply UITF, VTA, and CMTF simultaneously
Need to understand CTF user loads
Ability to regulate CMTF LHe pressure within 0.1 torr of setpoint
Ability to regulate CMTF, VTA, and UITF Lhe pressure independently, simultaneously
Redundant supply and return systems to allow half capacity during CTF maintenance periods
Replace existing VTA "pair pumps" with new units
In progress
Install 1000L D9 in VTA
Buffer dewar approach
12 December 2018

12. Summary Current performance is reasonably well-understood
Difficult to run CMTF & VTA simultaneously
Shared supply needs coordination
Shared recovery impacts pressure stability and liquefaction
Need to update cryo projection to include new projects
12 December 2018

13. Back Up
12 December 2018