Summary of BBLR Discussions on 11.07.2006

Participating: UD, JPK, FZ

1. G. Sterbini's thesis description 
   => FZ will send comments or suggested changes to JPK before Tuesday 18.07.

2. EPAC'06 paper
   => UD will send final version of BBTRACK paper to JPK and FZ

3. regular meetings on D0 detector integration organized by E. Tsesmelis
   => JPK will inform FZ about ATLAS contact for LUMI-06 workshop in Valencia

4. RHIC
   several groups are simulating the RHIC experiments;
   if effect is weak, we should explore how it can be enhanced,
   possibilities: tune, higher current, tune modulation, chromaticity;
   it was unclear whether the tune was held constant in the RHIC experiments, 
   and whether changes to the chromaticity were essential to observe an effect;
   if chromaticity is important, we might expect a bunch-length shrinkage

5. Different scaling with distance at SPS, Tevatron and RHIC;
   all pointing to low-order resonances; See Vladimir's email;
   may want to perform tune scan in the SPS to see if scaling and threshold change

6. DAFNE
   positive effect of wire compensation observed in LIFETRACK simulations and in reality;
   almost independent of excitation current;
   synchrotron radiation may be ignored; MAD-X model will be provided by Catia Milardi

7. => MD Programs for SPS and RHIC
   MD plan for SPS to be developed and proposed to GA
   RHIC MD proposal needs to foresee stronger excitation or additional perturbations  
   
8. pulsed wire
   no fast sampling oscilloscope presently available at CERN
   scope on loan at BNL may be sufficient to measure required jitter level;
   => JPK recommends contacting Remo Maccaferri as specialist for fast systems

9. Regular meetings on long-range beam-beam issues foreseen starting after summer break  

next discussion on 27 July



Appendix

earlier lists:

open questions and plans for 2006 (including FR's comments) 

- redo tune scan of compensation to understand why/if lifetime is not recovered at all tunes

- measure beam lifetime vs. beam-wire distance for different tunes 
    (to see whether different power laws seen at SPS (^5), Tevatron (^3) and RHIC (^2 and ^4) are tune related)

- study sensitivity of final emittance to tune with and without BBLR

- do SPS experiments at different energies to confirm/falsify extrapolation of 26 GeV data to 450/7000 GeV

- improve agreement between simulated and measured lifetime (higher beam energy?) 

- demonstrate that 10-4 stability of pulsed wire can be achieved 

- understand parameters which are out of control or introduce intentional large perturbation 
  (excite sextupoles, octupoles) to reconcile experiments and measurements

- wire compensation test with colliding beams (at RHIC) essential? 

- common observable in experiments & simulations? – dynamic aperture! lifetime?

- why is lifetime in PAC’05 paper ~15 minutes instead of ~5 minutes in other experiments?


BBLR issues:
   
- SPS tests at higher energy (55 GeV) with better lifetime than at 26 GeV

- lifetimes predicted by simulations are different from observed ones; 
  experimental control of amplitude detuning and resonance strengths

- demonstrate 1e-4 stability of wire current experimentally 

- effect of dc wire on PACMAN bunch

- why was PAC’05 lifetime better than EPAC04 lifetime?

- compare HV, HH and VV crossing

- triplet errors -> Stephane Fartoukh

- flat beam?

- Guido’s results

- experiments with 3rd wire