1. ILC-BDS Collimators - Simulation and Experiment Adriana Bungau The University of Manchester Group Annual Meeting December, 2007, Manchester Adriana Bungau The University of Manchester Group Annual Meeting December, 2007, Manchester

2. Content  Achievements 2007 - wakefield simulation - wakefield experiment at ESA - collimator design  Summary  Plans for 2008  Achievements 2007 - wakefield simulation - wakefield experiment at ESA - collimator design  Summary  Plans for 2008

3. Wakefield Simulations  The current implementation of the existing wakefield classes was changed to allow derrived classes for spoiler wakefields  Higher order mode wakefields were implemented in the tracking code  Wake potentials for simple geometry were used (taper + flat part +taper)  Resistive wakes assumed that the collimator material is titanium  The current implementation of the existing wakefield classes was changed to allow derrived classes for spoiler wakefields  Higher order mode wakefields were implemented in the tracking code  Wake potentials for simple geometry were used (taper + flat part +taper)  Resistive wakes assumed that the collimator material is titanium

4. Wakefield simulations  Emittance growth due to wakefiels was studied and its effect on luminosity at the IP  The changes made to the tracking code and the new classes are now integrated in the CVS repository at DESY  Emittance growth due to wakefiels was studied and its effect on luminosity at the IP  The changes made to the tracking code and the new classes are now integrated in the CVS repository at DESY

5. SLAC -ESA Experiment  collimator wakefields of various geometries, material and having either a rough surface or polished were measured at ESA  Two runs: March and July  Measured the kick as a function of the collimator position  Data was analysed on the Manchester cluster (setup and then upgraded the data analysis packages)  BPM callibration and conversion of data files from the crude format into root files (with Lancaster Univ)  collimator wakefields of various geometries, material and having either a rough surface or polished were measured at ESA  Two runs: March and July  Measured the kick as a function of the collimator position  Data was analysed on the Manchester cluster (setup and then upgraded the data analysis packages)  BPM callibration and conversion of data files from the crude format into root files (with Lancaster Univ)

6. Collimator design  collimator design using Geant4 (A.Bungau) and Fluka (L. Fernandez) was established by the beginning of this year  Experiment will now follow (DL+RAL+Birmingham Univ )  collimator design using Geant4 (A.Bungau) and Fluka (L. Fernandez) was established by the beginning of this year  Experiment will now follow (DL+RAL+Birmingham Univ )

7. Publications 2007  - "Emittance Growth Due to Higher Order Angular Multipole Mode Wakefields in the ILC-BDS Collimators" - PAC 2007, New Mexico  - "Wakefield Models for Particle Tracking Codes" - PAC 2007, New Mexico  - "Measurements of the Transverse Wakefields Due to Varying Collimator Characteristics" - PAC 2007, New Mexico  - "Collimator Wakefields: Formulae and Simulation" - PAC 2007, New Mexico  - "Emittance Growth Due to Higher Order Mode Wakefields in the ILC-BDS Collimators for Small Offsets" - EuroTev Report  - "Emittance Growth Due to Higher Order Angular Multipole Mode Wakefields in the ILC-BDS Collimators" - PAC 2007, New Mexico  - "Wakefield Models for Particle Tracking Codes" - PAC 2007, New Mexico  - "Measurements of the Transverse Wakefields Due to Varying Collimator Characteristics" - PAC 2007, New Mexico  - "Collimator Wakefields: Formulae and Simulation" - PAC 2007, New Mexico  - "Emittance Growth Due to Higher Order Mode Wakefields in the ILC-BDS Collimators for Small Offsets" - EuroTev Report

8. Talks 2007 - Implementation of Higher Order Wakefields in Merlin - European Linear Collider Workshop, Daresbury - Collimator Design and Short Range Wakefields, CERN, Colsim meeting - Some Wakefield studies, CERN, Colsim meeting (with Roger Barlow) - ILC_BDS Collimator study, CERN, Colsim meeting - Wakefields in the ILC_BDS Collimators, Cockcroft Institute - 3rd Wakefield Workshop, Daresbury http://www.hep.man.ac.uk/u/adriana - Implementation of Higher Order Wakefields in Merlin - European Linear Collider Workshop, Daresbury - Collimator Design and Short Range Wakefields, CERN, Colsim meeting - Some Wakefield studies, CERN, Colsim meeting (with Roger Barlow) - ILC_BDS Collimator study, CERN, Colsim meeting - Wakefields in the ILC_BDS Collimators, Cockcroft Institute - 3rd Wakefield Workshop, Daresbury http://www.hep.man.ac.uk/u/adriana

9. Summary  The collimator design is now done and benchmark between 3 codes is in good agreement (Geant4, Fluka, EGS)  Testing the collimator prototype for the damage scenario will now follow at KEK  Modelling of higher order mode wakefields was done for Ti Collimators with circular apertures  Changes to the Merlin code are uploaded at DESY  The collimator design is now done and benchmark between 3 codes is in good agreement (Geant4, Fluka, EGS)  Testing the collimator prototype for the damage scenario will now follow at KEK  Modelling of higher order mode wakefields was done for Ti Collimators with circular apertures  Changes to the Merlin code are uploaded at DESY

10. To Be Done  Initially Proposed : - carry on the work on collimator wakefields (implement Gdfidl/Echo results into Merlin) - shifts at ESA in the 2008 runs - start the work on pozitron beamline: - optimization of the spoiler position in the positron collimation system +beam studies - design of a hardware piece inside the helical undulator and calculate the energy deposition on it BUT: WITH THE ILC UNDER THREAT FROM STFC, THE LONG AND SHORT TERM GOALS MIGHT LOOK DIFFERENT NEXT YEAR!  Initially Proposed : - carry on the work on collimator wakefields (implement Gdfidl/Echo results into Merlin) - shifts at ESA in the 2008 runs - start the work on pozitron beamline: - optimization of the spoiler position in the positron collimation system +beam studies - design of a hardware piece inside the helical undulator and calculate the energy deposition on it BUT: WITH THE ILC UNDER THREAT FROM STFC, THE LONG AND SHORT TERM GOALS MIGHT LOOK DIFFERENT NEXT YEAR!