Quadrupole Shielded-Pickup Data Comparison of Signals from 10- and 20-Bunch e+ Trains -- Trapping ! -- -- Updated after meeting to include suggested.

Slides:

Advertisements

Similar presentations

Study of Resonance Crossing in FFAG Masamitsu Aiba (KEK) Contents 1.Introduction 2.Crossing experiment at PoP FFAG 3.Crossing experiment at HIMAC synchrotron.

Advertisements

Electron cloud tune shift measurements for long trains Tune Shift versus current: Measured the tune shift for 45 and 115 bunch positron trains with 14ns.

CESR Synchrotron Radiation Tables - Range of Photon Rates and Beta-averaged Photon Rates - Jim Crittenden Cornell Laboratory for Accelerator-Based Sciences.

Comparison of ECLOUD and POSINST Calculations of Coherent Tune Shifts with Emphasis on the Relative Drift and Dipole Contributions Jim Crittenden Cornell.

45 th ICFA Beam Dynamic Workshop June 8–12, 2009, Cornell University, Ithaca New York Jim Crittenden & John Sikora Cornell Laboratory for Accelerator-Based.

ECLOUD Calculations of Field Gradients During Bunch Passage Jim Crittenden Cornell Laboratory for Accelerator-Based Sciences and Education Electron Cloud.

Early Results on a Search for Cyclotron Resonances in ECLOUD -- Collaboration with Eric Wilkinson -- These slides includes corrections arising from the.

45 th ICFA Beam Dynamic Workshop June 8–12, 2009, Cornell University, Ithaca New York Resolution of ECLOUD Tune Shift Calculation Instability Jim Crittenden.

45 th ICFA Beam Dynamic Workshop June 8–12, 2009, Cornell University, Ithaca New York Modelling Cyclotron Resonances in ECLOUD 1) Comparison with CesrTA.

45 th ICFA Beam Dynamic Workshop June 8–12, 2009, Cornell University, Ithaca New York ECLOUD Simulations for the Tune Shift Measurements of December.

ECLOUD Calculations of Coherent Tune Shifts for the April 2007 Measurements - Study of SEY Model Effects - Jim Crittenden Cornell Laboratory for Accelerator-Based.

ECLOUD Calculations of Coherent Tune Shifts for the April 2007 Measurements - Study of SEY Model Effects - Jim Crittenden Cornell Laboratory for Accelerator-Based.

ECLOUD Calculations of Coherent Tune Shifts for the April 2007 and January 2009 Measurements - Preparation for PAC2009 FR5RF Paper and Poster - “Effects.

LEPP, the Cornell University Laboratory for Elementary-Particle Physics, has joined with CHESS to become the Cornell Laboratory for Accelerator-based Sciences.

45 th ICFA Beam Dynamic Workshop June 8–12, 2009, Cornell University, Ithaca New York Modeling Cyclotron Resonances in ECLOUD Jim Crittenden Cornell Laboratory.

45 th ICFA Beam Dynamic Workshop June 8–12, 2009, Cornell University, Ithaca New York Comparison of ECLOUD Calculations in Dipole and Quadrupole Fields.

ECLOUD Calculations of Coherent Tune Shifts for the April 2007 Measurements - This presentation limited to resolving drift/dipole weighting question -

45 th ICFA Beam Dynamic Workshop June 8–12, 2009, Cornell University, Ithaca New York Jim Crittenden Cornell Laboratory for Accelerator-Based Sciences.

45 th ICFA Beam Dynamic Workshop June 8–12, 2009, Cornell University, Ithaca New York Recent Studies with ECLOUD Jim Crittenden Cornell Laboratory for.

ElectronsdFud Simulation Work at Cornell Jim Crittenden Cornell Laboratory for Accelerator-Based Sciences and Education.

Space Charge Electric-Field Calculations for Coherent Tune Shift Estimations using the Electron-cloud Modelling Algorithm ECLOUD Jim Crittenden Cornell.

ECLOUD Calculations of Coherent Tune Shifts for the April 2007 Measurements - Thanks to Marco for clarifying the drift/dipole weighting - - Thanks to Gerry.

45 th ICFA Beam Dynamic Workshop June 8–12, 2009, Cornell University, Ithaca New York ECLOUD Simulations for the Tune Shift Measurements of December.

45 th ICFA Beam Dynamic Workshop June 8–12, 2009, Cornell University, Ithaca New York Comparison of ECLOUD Calculations in Dipole and Quadrupole Fields.

CESR Synchrotron Radiation Tables and Electron Cloud Modelling Input Parameters Jim Crittenden Cornell Laboratory for Accelerator-Based Sciences and Education.

45 th ICFA Beam Dynamic Workshop June 8–12, 2009, Cornell University, Ithaca New York Jim Crittenden Cornell Laboratory for Accelerator-Based Sciences.

45 th ICFA Beam Dynamic Workshop June 8–12, 2009, Cornell University, Ithaca New York Jim Crittenden Cornell Laboratory for Accelerator-Based Sciences.

45 th ICFA Beam Dynamic Workshop June 8–12, 2009, Cornell University, Ithaca New York Jim Crittenden Cornell Laboratory for Accelerator-Based Sciences.

Electron Cloud Simulations Using ORBIT Code - Cold Proton Bunch model April 11, 2007 ECLOUD07 Yoichi Sato, Nishina Center, RIKEN 1 Y. Sato ECLOUD07.

Witness Bunch Experimental Studies at CESR-TA Robert Holtzapple Alfred University/Cal Poly San Luis Obispo.

November 18, 2011David L. Rubin1 CESR Test Accelerator – Investigation of the physics of charged particle beams Circumference = 768m - Beam energy

Shielded-Pickup Measurements in June and Update on Modeling Results / J.A. Crittenden 23 August / 4 Shielded-Pickup Measurements in June and Update.

2nd International Particle Accelerator Conference September 4–9, 2011, San Sebastián, Spain LEPP, the Cornell University Laboratory for Elementary-Particle.

RFA Simulations Joe Calvey LEPP, Cornell University 6/25/09.

Professor Philip Burrows John Adams Institute for Accelerator Science Oxford University ACAS School for Accelerator Physics January 2014 Longitudinal Dynamics.

45 th ICFA Beam Dynamic Workshop June 8–12, 2009, Cornell University, Ithaca New York Jim Crittenden Cornell Laboratory for Accelerator-Based Sciences.

45 th ICFA Beam Dynamic Workshop June 8–12, 2009, Cornell University, Ithaca New York Jim Crittenden Cornell Laboratory for Accelerator-Based Sciences.

45 th ICFA Beam Dynamic Workshop June 8–12, 2009, Cornell University, Ithaca New York Jim Crittenden & John Sikora Cornell Laboratory for Accelerator-Based.

45 th ICFA Beam Dynamic Workshop June 8–12, 2009, Cornell University, Ithaca New York Jim Crittenden Cornell Laboratory for Accelerator-Based Sciences.

LEPP, the Cornell University Laboratory for Elementary-Particle Physics, has joined with CHESS to become the Cornell Laboratory for Accelerator-based Sciences.

45 th ICFA Beam Dynamic Workshop June 8–12, 2009, Cornell University, Ithaca New York Jared Ginsberg Cornell Laboratory for Accelerator-Based Sciences.

Status of ECLOUD Simulations for the Shielded Button Measurements

Jim Crittenden CHESS Simulation Working Group 30 March 2015

Update to ECLOUD Calculations for the

Electron Cloud Measurement Summary for the April 2014 Run

Electron Cloud R&D at Cornell ILCDR08--7/8/08

Ben Cerio Office of Science, SULI Program 2006

Using Time-Resolved Retarding Field Analyzer Measurements to Determine the SEY Mitigation Effectiveness of Grooves -- Bonus: first look at last night's.

RECENT DEVELOPMENTS IN MODELING

Electron Cloud Meeting

Physics Scope and Work Plan for the Shielded-Pickup Measurements -- Synchrotron Radiation Photon Distributions Photoelectron Production Parameters.

First Look at the New SYNRAD3D Results

Detailed Characterization of Vacuum Chamber Surface Properties Using Measurements of the Time Dependence of Electron Cloud Development Jim Crittenden.

RECENT DEVELOPMENTS IN MODELING

Use of the Shielded-Pickup Measurements for Optimization of the Photoelectron Production Energy Distribution in ECLOUD -- This topic was included in the.

Physics Scope and Work Plan for the Shielded-Pickup Measurements -- Synchrotron Radiation Photon Distributions Photoelectron Production Parameters.

First Look at Modeling Photoelectron Energy Distribution for a 2

Shielded Button Measurement/ECLOUD Simulation Comparison for 5

Electron Cloud Meeting

Why Study Electron Clouds? Methods and Tools to Study Electron Clouds

Ryan Badman Jim Crittenden July 20, 2011 Electron Cloud Meeting

First Attempt to Simulate the Shielded Button Measurements with ECLOUD

J.A.Crittenden, Y.Li, X.Liu, M.A.Palmer, J.P.Sikora (Cornell)

All material for this talk may be obtained at

Jim Crittenden Electron Cloud/Impedance Meeting 27 May 2015

CESRTA Measurement of Electron Cloud Density by TE Wave and RFA

Wednesday Week 2 Lecture

Electron cloud studies at CESR

CTA 09 - Introduction David Rubin Cornell Laboratory for

Chicane and Bunch Spacing Scans

Presentation transcript:

Quadrupole Shielded-Pickup Data Comparison of Signals from 10- and 20-Bunch e+ Trains -- Trapping ! -- -- Updated after meeting to include suggested measurements -- Chris Shill, Jim Crittenden & John Sikora Cornell Laboratory for Accelerator-Based Sciences and Education Electron Cloud Meeting 3 July 2013

Recent June QSPU Measurements of 10- and 20-Bunch e+ Trains The cloud buildup process exhibits a distinct change in behavior after six bunches. How do the first six bunches know that the last ten bunches are coming ? Do they know those ten trailing bunches were (or were not) there on the preceding turn(s) ? Such a phenomenon has not been observed in SPU data or TR_RFA data with or without a dipole magnetic field.

Was the effect already present in the April measurements? Yes. June April April The same “memory effect” occurs in both the June and April data. (Why is the 20-bunch signal so much larger in June?)

Compare slopes for 10- and 20-bunch trains 10-bunch signal doubled April The 6-bunch slope is a factor of two higher for the 20-bunch train, i.e. it scales with the total train current. Proposed Interpretation A reservoir of cloud electrons has collected (or remained) during the turn prior to the arrival of the train. Each of the first six bunches sweeps out 1/6th of the reservoir. The number of electrons stored in the reservoir scales with train current. After the reservoir is empty, the cloud builds up using only newly produced electrons.

Dependence on Bunch Current 2 mA 4 mA 6 mA The 20-bunch signal increases from 2 mV to 80 mV when the bunch current increases from 2 mA to 10 mA/bunch. The transition occurs after the sixth bunch independent of bunch current. Nonlinear (resonant?) behavior with bunch current (6 mA is “special”). 8 mA 10 mA

Future Measurements and Modeling Informative experiments Why do six bunches suffice to clear the trapped electrons ? Does each of the six bunches clear the same number of electrons? - Finer steps in bunch current (map out nonlinearity) - Dependence on bunch spacing (still six bunches to clear?) - Vary bunch current in the first six bunches - Dependence on train length (< 6 ?) - Beam energy (less light?). Electron beam. - Can we vary the quadrupole field strength? - Suggestions? 1) Witness TRAINS 2) Orbit dependence Modeling If six bunches suffice to clear all the trapped electrons, it may suffice to model just two trains, i.e. 1 turn + 1 train. - Need to develop QSPU acceptance model - Study dependence on bunch current, spacing, field strength - How do the cloud and QSPU signal evolve from turn to turn? April