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

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

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

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 1 2 3 4 5 6 7 8 8 dewars (capacity range ~200 to 2000 liters) 12 December 2018

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 0.0483 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

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

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

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

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

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

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

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

Back Up 12 December 2018