Difference between revisions of "PITMinutes 04-09-2018"

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(New page: == Attendance == R. Bachimanchi, K. Baggett, J. Benesch, R. Geng, C. Hovater, G. Krafft, A. Kimber, F. Marhauser, C. Mounts, R. Nelson, T. Plawski, T. Powers, C. Reece, and R. Rimmer. ==...)
 
(→‎Agenda and Notes)
 
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== Attendance ==
 
== Attendance ==
  
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R. Bachimanchi, K. Baggett, J. Benesch, R. Geng, C. Hovater, G. Krafft, A. Kimber, F. Marhauser, C. Mounts, R. Nelson, T. Plawski, T. Powers, C. Reece, and R. Rimmer.
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R. Bachimanchi, K. Baggett, M. Drury, A. Freyberger, R. Geng, A. Hutton, G. Krafft, A. Kimber, R. Legg, C. Mounts, R. Nelson, T. Plawski, T. Powers, C. Reece, T. Reilly, R. Rimmer, and A. Solopova.
  
 
== Agenda and Notes ==
 
== Agenda and Notes ==
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1. Operations Status and Summary/Review (Freyberger)
 
1. Operations Status and Summary/Review (Freyberger)
  
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Four Hall Ops has started. Have had a rough couple weeks
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High average current limits remain. Usually A runs 22.5 muA
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as the beam average current was raised. CEBAF seems to have
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and C runs 50-60 muA. Seems more and more solid that the Hall
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an average current limit around the spec average current of
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C current limit is 70-75 muA, independent of the Hall A current.
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460 muA 5 pass beam. This current has been briefly achieved,
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And the main trips are from beam loss. So focus is shifting
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but steady OPs at around 325 muA. BBU looked for but none
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back to injector. Today, bunch length measurements are being
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obviously present. Much optics work has cleaned up beam and
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made for the different Hall bunches. Recent work points
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made more substantial apertures, but the average current limitation
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to longitudinal phase space tails causing high
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remains. OPS trip rates now dominated by RF trips.
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average current trips. Is there a better diagnostic for these?
  
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C75 Review completed. Will post review report when available.
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Anna will be working on getting a handle on OPS-initiated
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reductions in the C100 cavity gradients. First try to understand
 +
why people are reducing them and work through mitigations.
  
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RF separators seem to have settled down. circulator loads unstable.
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C75 Review completed. Here is the review report.
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Recovery reboot?
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2. Beam Loading and Q_ext (Krafft)
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[https://casa.jlab.org/LINACPIT/TN-18-012_Feb_2018_C75_review_report.pdf C75 Review Report]
  
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Jay has gathered some data that indicates that perhaps
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2. Radiation Reduction with Lead Collars (Legg)
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the Q_ext on many cavities is incorrect. This means the
+
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RF systems are not matched to the cavities at the highest
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operating currents, leading to addition power loads on
+
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the klystrons. Could this be a contributor to the average
+
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current limits?
+
  
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[https://casa.jlab.org/LINACPIT/Full_Power_Test_Note_98-009.pdf Full Power Test Note]
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[https://casa.jlab.org/LINACPIT/Lead_Collars_For_C100s_03212018.pdf C100 Lead Collar Update]
  
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[https://casa.jlab.org/LINACPIT/Optimal_Qext.ppt Presentation on Optimal Qext]
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3. More on Beam Loading and Q_ext (Krafft)
  
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[https://casa.jlab.org/LINACPIT/ced_20feb2018.txt CED All Qs list]
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[https://casa.jlab.org/LINACPIT/Full_Power_Test_Note_98-009.pdf Full Power Test Note]
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+
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[https://casa.jlab.org/LINACPIT/RF_Power_C75.xlsx Xcel with power calculations]
+
−
 
+
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3. C100 Refurbishment Planning (Freyberger)
+
−
 
+
−
Jay has gathered some data that indicates that perhaps
+
−
the Q_ext on many cavities is incorrect. This means the
+
−
RF systems are not matched to the cavities at the highest
+
−
operating currents, leading to addition power loads on
+
−
the klystrons. Could this be a contributor to the average
+
−
current limits?
+
−
 
+
−
[https://casa.jlab.org/LINACPIT/Optimal_Qext.ppt Presentation on Optimal Qext]
+
  
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[https://casa.jlab.org/LINACPIT/ced_20feb2018.txt CED All Qs list]
+
[https://casa.jlab.org/LINACPIT/More_Optimal_Qext.ppt Additional Information on Optimal Qext]
  
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[https://casa.jlab.org/LINACPIT/RF_Power_C75.xlsx Xcel with power calculations]
+
4. C100 Refurbishment Planning (Freyberger)
  
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3. Draft Cryomodule Specification (Benesch)
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5. Draft Cryomodule Specification (Benesch)
  
 
Jay has written up a set of goals for the cryomodules:
 
Jay has written up a set of goals for the cryomodules:
 
[https://casa.jlab.org/LINACPIT/2017CM_specR2.pdf Draft Cryomodule Specification]
 
[https://casa.jlab.org/LINACPIT/2017CM_specR2.pdf Draft Cryomodule Specification]
  
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4. Draft Acceptance Criteria (Legg)
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6. Draft Acceptance Criteria (Legg)
  
 
Bob shared the LCLS II module acceptance criteria that the
 
Bob shared the LCLS II module acceptance criteria that the

Latest revision as of 09:02, 10 April 2018

Attendance

R. Bachimanchi, K. Baggett, M. Drury, A. Freyberger, R. Geng, A. Hutton, G. Krafft, A. Kimber, R. Legg, C. Mounts, R. Nelson, T. Plawski, T. Powers, C. Reece, T. Reilly, R. Rimmer, and A. Solopova.

Agenda and Notes

1. Operations Status and Summary/Review (Freyberger)

High average current limits remain. Usually A runs 22.5 muA and C runs 50-60 muA. Seems more and more solid that the Hall C current limit is 70-75 muA, independent of the Hall A current. And the main trips are from beam loss. So focus is shifting back to injector. Today, bunch length measurements are being made for the different Hall bunches. Recent work points to longitudinal phase space tails causing high average current trips. Is there a better diagnostic for these?

Anna will be working on getting a handle on OPS-initiated reductions in the C100 cavity gradients. First try to understand why people are reducing them and work through mitigations.

C75 Review completed. Here is the review report.

C75 Review Report

2. Radiation Reduction with Lead Collars (Legg)

C100 Lead Collar Update

3. More on Beam Loading and Q_ext (Krafft)

Full Power Test Note

Additional Information on Optimal Qext

4. C100 Refurbishment Planning (Freyberger)

5. Draft Cryomodule Specification (Benesch)

Jay has written up a set of goals for the cryomodules: Draft Cryomodule Specification

6. Draft Acceptance Criteria (Legg)

Bob shared the LCLS II module acceptance criteria that the LCLS II project is working under. We should perhaps adopt something similar for C75? (Discuss Pros and Cons)

LCLS II Module Acceptance Criteria

Frank and Gigi (mainly) have written up a C75 performance specification document.

JLAB-TN-17-055: Draft C75 Specification Document

Action Items

Leadership of quenches. Offline discussion.

Complete C75 Module Specifications (Marhauser, Benesch, Krafft)

C100 Refurbishment Project for the future?

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