Thoughts on Energy Reach Arne Freyberger Operations Department Accelerator Division 2017 Ops StayTreat

Welcome to StayTreat #4!!! Energy Reach has been a major component of previous StayTreats.

2017 Operation StayTreat OPS DIR Facilities SRF External(SLAC) DOE Elec. ENG CASA CRYO

CEBAF System Availability Weekly availability reviews at the weekly scheduling meeting Early identification of issues Monthly availability report Presented and discussed on the first Friday of a new month at the daily 8am meeting Look for trends Increased statistics for better information Annual availability review is used to set priority for support groups annual work plan (AWP). Feb. 2017 shown A good month FSD Trip rate: 91.7 % Availability RF System: 95.4% Availability FSD*RF = 87.4% If Availability goal is 70%, the other 14 system must have an Availability > 80% Every other system must be > 0.8^(1/14) = 98% Energy Reach is more than integrated gradient, system availability at the chosen gradient is IMPORTANT!!

RF MTBF: about two events per day MTTR: low, less than 1h Would better training of operators improve MTTR even more? Improved controls?

Vacuum Dominated by SRF window failure in Nov 2017

CEBAF Performance Plan Define the performance goals Availability/Reliability Beam Parameters (emittance, energy spread, bunch charge, beam energy) Peak Conditions (Hall multiplicity, operating weeks,…) Perform gap analysis to identify where present CEBAF performance does not achieve the performance goals Develop a plan to close the gaps

12GeV NP Program: 2.2 GeV/pass centric Slide from 2016 C75 review

CEBAF 20 year view A miracle occurs

CEBAF Performance Goals

Energy Gap and Plan Energy Gap: Presently CEBAF cannot support design energy (FY17/FY18 operations at 4% below design) Annual gradient loss exceeds the gain from one C50/year One C50/year insufficient to maintain energy reach; gap is growing! Energy Plan: C75 Upgrade: replace the C20 cavities with high current 5-cell cavities Re-use as much of the cryomodule as possible Total cost in terms of MV/$ lower than C50 or C100 options Upgrade LLRF to digital controls (similar to C100) Target specifications: Gradient: 18.5 MV/m Q0 > 8e9 Upgrade warm region vacuum and clean (SRF quality processing) all warm vacuum regions two warm girders/year (continues to end of 12GeV/era) Upgrade analog LLRF with digital LLRF in all zones two zones per year (continues to end of 12GeV era)

Energy Gap and Plan (C75 Upgrades) Proposed path to design energy (1090 MeV/linac) Comparable to C50 program post hurricane Isabel If annual degradation is mitigated: might achieve 1090 MeV/linac by FY21 and with fewer C75 modules

Preliminary Performance Plan M&S Cost Estimate C75s C100-Refurbs Preliminary Near term goal is to close the gaps by FY23 Plan emphasizes improving CEBAF availability/reliability first: Energy Reach second Operating at optimal weeks third All dollar values in FY17 direct costs

StayTreat Goals Are we missing something in regards to CEBAF Availability? Can we improve the DTM data? Are we using the DTM data to its fullest potential? Is the impact on System Availability part of the JLab culture? Are we ready to implement the CEBAF Performance Plan? Are we missing something in regards to CEBAF Energy Reach? What is the root cause of C100 under performance? (This issue is now 3 years old, see 2014 StayTreat)

Backup

Optimizing 12GeV Operations Reliability/Availability Focus 4-Hall Operations Improved Linac/Cryogenic procedures: Reduce risk of cryoplant contamination due to He connections/disconnections Linac LHe Pressure optimization Address end-of-life issues: SRF C20 Warm poly RF windows SRF C20/C50 end-can O-rings Improve C100 warm girder tolerance to radiation environment Identify and correct errant magnets West Arc to East Arc extension cable, allows for West Arc power supply to power East Arc magnets. Provides CEBAF the ability to support a full ABC program in the event of an East Arc box power supply failure. Energy Reach/Gradient Maintenance Linac energy setting: margin -> reliable operations Identify source of SRF Particulate Cleaning/processing warm girder regions Improved tunnel vacuum procedures