Minutes of the ICE section
12th meeting on Wednesday 10/11/2010 (08:40-10:30, 6/2-004)
ICE members: Benoit Salvant (BS), Christian Hansen (CH), Carlo Zannini (CZ), Diego Quatraro (DQ), Hugo Alistair Day (HD), Elena Benedetto (EB), Ewen Hamish Maclean (EHM), Elias Metral (EM), Elena Wildner (EW), Frank Schmidt (FS), Giovanni Rumolo (GR), Jean-Luc Nougaret (JLN), Kevin Shing Bruce Li (KL), Maria Carmen Alabau Pons (MCAP), Nicolo Biancacci (NB), Nicolas Mounet (NM), Olav Ejner Berrig (OB), Tatiana Pieloni (TP), Werner Herr (WH).
Present/Excused: BS, CH, CZ, DQ, HD, EB, EHM, EM, EW, FS, GR, JLN, KL, MCAP, NB, NM, OB, TP, WH, Rama Calaga, Fritz Caspers, Emanuele Laface, Riccardo de Maria.
1) General infos
- No particular comment from anyone.
- No SL meeting last week.
- News on the LHC:
- 1st injections with 50 ns beam on FR 29/10/10 and the beam was unstable.
- Then, "clear" ecloud observations: both in warm and cold sections => Seems to be consistent with SEY of ~ 2.5 for the simulations, which is the case for a vacuum chamber in copper which is unbaked (between 2 and 2.5 can be obtained). WH said that our group never considered a SEY > 1.7 in the past.
- WH summary for the beam-beam measurements in the LHC:
- PACMAN bunches will be a problem in the future in the LHC.
- Coherent beam-beam was seen.
- Long-range not so much for the moment.
- Issue with ALICE separation.
- In the SPS we had also ~ 0.02 in the past for the HO BB tune shift, which therefore should be feasible in the LHC. But LR will/should reduce it.
- We should put a high weight on the crab cavities for the lumi upgrade due to the recent observations.
- FritzC mentioned that for ecloud studies a microwave installation in the LHC is a major project and would require some time.
- FritzC also mentioned that we should hope that the magnetron effect will not be seen.
- Info which I sent before the meeting:
- Next TSC: Deadline 25/11/2010 (TSC on 07/12/2010) => Contact Catherine Rossat to have the electronic access to the folder + short description (~ 5 lines) of the proposed work.
- Talk on FR on the "1st direct observation of dust trapping" by Dr. Tanimoto.
2) Trip reports and software plans for the upgrade (FS): ppt
- FS discussed the AAC at Fermilab, the APEX at BNL and the plans for BB software.
- AAC at Fermilab:
- The Accerator Advisory Committee (AAC) has been convened from the 28th to the 30th of July 2010 at Fermilab.
- One of the goals has been to review the proposed experiments for the post-Run II studies.
- Proposals were put forward by the Tevatron, BNL & CERN
- Recommendations => Consequence and plan.
- APEX at BNL (RHIC's annual Accelerator Physics EXperiment workshop):
- Goals:
- Improve machine performance: RHIC and Injector chain.
- Support developments for RHIC future: eRHIC, coherent electron cooling.
- Support beam instrumentation development: RHIC, AGS, future facilities like pEDM.
- Inter-lab collaboration: LHC, Tevatron, CEBAF => Main reason for FS to attend it.
- Enrich accelerator physics knowledge.
- Summary:
- Run-11: 250 GeV polarized protons goals
P = 35
-> 50%, Beta* = 0.7 -> 0.6 m, Nb = 1.1 -> 1.4E11- Run-11: 100 GeV/nucleon goals
Beta* = 0.75
-> 0.65 m, Nb = 1.1 -> 1.1E9 (?), more cooling- To allow for lower Beta* need to implement reliable optics measurement and correction
- Further polarized beam upgrades:
- Polarized source upgrade: 10x intensity, ~5% more polarization (2013).
- Electron lenses: up to 2x luminosity with source upgrade (2013).
- In-situ pipe coating: SEYand rho reduction (start >2013)
- New developments.
- Inter-lab collaboration:
- Strong interest in the LHC Online Model
- Massive Tracking planned with BOINC (LHC@HOME) for e-lens tracking. This element has been included by BNL and Eric McIntosh has prepared the SixTrack run environment
=> Could be of use for LHC upgrade?- 6D element in Sixtrack has been tested, apparently weaker than expected? WH commented that the effect should be small and that nothing was seen in the past with protons (only something seen with leptons).
- Plan is to benchmark all BB codes of the 3 Labs: CERN, FERMILAB & BNL => To this end extended studies planned for beginning of next year.
- Plans for BB software - LHC Upgrade Requirements:
- For the LHC upgrade more severe parameters and/or new techniques might be required.
- One option is to use flat instead of round beams.
- It also seems that the crossing angle will be larger than for the nominal LHC version.
- Both requires to use SixTrack differently than before:
- Presently SixTrack has been set up to make use of the LHC anti-symmetry to calculate BB for round beams => A true flat option makes code modifications necessary.
- The larger crossing angle raises the question if the plain 4D BB description is still adequate => SixTrack has the 6D BB lens implemented la Ripken.
- Flat beams in SixTrack:
- EmanueleL has implemented a first version of flat beams by passing the sigma values to SixTrack via a file produced by MAD.
- This is a good approximation but a small issue remains in case of strong coupling.
- Eventually this will require to implement the BB force in the MAD-X PTC converter. This will be done in the future but will require extensive testing.
- Nevertheless the present solution seems to be sufficient for the case of the LHC upgrade.
- Once the benchmarking is finished and its usage is documented we are ready for the upgrade.
- 6D BB lens in SixTrack:
- Some 10 years ago Gerhard Ripken visited us and had derived a formalism of the 6D BB lens including coupling. This is an extension of the original work by Hirata.
- Peter Leunissen implemented this 6D lens into SixTrack.
- Besides basic tests it has not been benchmarked nor used extensively.
- Since the needs arises now, the code will be reviewed and benchmarked with external codes.
- Reminder: In lifetrack there is also the 6D BB lens from Hirata and this is why we can benchmark.
- Reminder on all the beam-beam tools needed, in increasing order of complexity (see 3rd ICE meeting, 28/07/2010). Action 1-2-3: FS and beam-beam team.
1) Possibility to make some tracking with SIXTRACK when betax* ≠ betay*, called flat beams. It is worth mentioning that 3 cases might be referred to as flat beams: betax* ≠ betay* (the case of interest here), epsx ≠ epsy and flat longitudinal distribution. In the case of betax* ≠ betay*, the output of MADX is fine (it is well computed) but the problem is then the data transfer between MADX and SIXTRACK => Not all the parameters (betas, sizes, intensities) are transferred. For the other two "flat" cases it should be fine.
2) 6D beam-beam lens (in fact it is 4D + time dependence) => We need this even if the strong beam is a single particle. There is a lens in SIXTRACK but it is not debugged. For instance it is not clear if the crossing angle is defined for the strong or the weak beam.
3) Effect of the 6D beam-beam lens on the strong beam => Both the divergence effect of the strong beam and crab tilt.
3) ZBASE status (JLN): ppt
- JLN presented the database schema for ZBASE, the impedance database => Motivation, data storage requirements and architecture.
- Previous implementations with a GUI: ZBASE (1996), ZBASE3 (2006) now replaced by a Matlab program.
- Organizing the data with standard relational database:
- Rely on a self-describing data system.
- Insulate program from data.
- Manage data with SQL.
- Provide data backup, recovery, transactions and JDBC...
- Data storage requirements => Derived data are not stored.
- Reminder on some technical terms:
- SQL = Sequential Query Language.
- JDBC = Java DataBase Connectivity Interface.
- IPC = Inter-Process Communication.
- DDL = Data Definition Language.
- An SQL CLOB is a built-in type that stores a Character Large Object as a column value in a row of a database table.
- DML = Data Manipulation Language.
- Architecture:
- ZBASE is a Java application.
- For a user to store, retrieve and process impedance data.
- The Java application runs on the client computer.
- The database itself lives on a dedicated Oracle server.
- The Java application issues queries in SQL. The server retrieves data from the database and sends them through IPC.
- The schema is a model that structures the data stored in the Oracle database
- And which serves as a foundation to build the Java application. In a database application, the schema is therefore of paramount importance.
- In addition stored procedures can be invoked on the server-side.
- The conceptual model of the database depicts the key concepts and how they relate to each other.
- Snapshot of the GUI of the ZBASE application prototype.
- Conclusion and future work:
- Database schema:
- Almost complete.
- Java application:
- CST simulation storage and retrieval.
- Sum implementation to be improved.
- Populating the database:
- Nothing done.
- Identify some families to be stored first.
4) Actions to be taken for the next meeting
- Old actions.
- New actions (beam-beam tools needed, in increasing order of complexity (see 3rd ICE meeting, 28/07/2010)):
- Action 1 (FS and beam-beam team): Possibility to make some tracking with SIXTRACK when betax* ≠ betay*, called flat beams. It is worth mentioning that 3 cases might be referred to as flat beams: betax* ≠ betay* (the case of interest here), epsx ≠ epsy and flat longitudinal distribution. In the case of betax* ≠ betay*, the output of MADX is fine (it is well computed) but the problem is then the data transfer between MADX and SIXTRACK => Not all the parameters (betas, sizes, intensities) are transferred. For the other two "flat" cases it should be fine.
- Action 2 (FS and beam-beam team): 6D beam-beam lens (in fact it is 4D + time dependence) => We need this even if the strong beam is a single particle. There is a lens in SIXTRACK but it is not debugged. For instance it is not clear if the crossing angle is defined for the strong or the weak beam.
- Action 3 (FS and beam-beam team): Effect of the 6D beam-beam lens on the strong beam => Both the divergence effect of the strong beam and crab tilt.
5) Miscellaneous
- The next (13th) meeting will take place on 24/11/2010 => Agenda:
1) Ecloud activities for the LHC (FZ).
2) Material characterization method and ferrite's results (Christine Vollinger, BE/RF).
3) IR3MBC collimators status (NM).
- See preliminary agendas for the next meetings.
Minutes by E. Metral, 03/01/2011.