1. TJR 01/21/2003Slide 1 Simulations of the Study 2 Cooling Channel with Realistic Absorber Windows Tom Roberts Illinois Institute of Technology

2. TJR 01/21/2003Slide 2 Geant4 Simulations This is a complete reimplementation of the Study 2 Cooling channel –Geant4 5.0 –Fermilab Beam Tools 1.0 –HistoScope 5.0 All results use the 2631 events from EmittBunch5-207-Cooler.hst

3. TJR 01/21/2003Slide 3 Bellows Absorber Windows Aluminum 36 cm 5 cm 10 cm 216 u135 u 35 cm (This is a hand-drawn figure roughly to scale, actual window data are from H2-Bellow-Window-concave-convex-coord-2 (1).xls) LH 2 Vacuum Best Guess Simple Guesses

4. TJR 01/21/2003Slide 4 Tuning RF Cavities The approximation used to set the RF cavity timing is not good enough – synchrotron oscillations for the center particle of 5-10 MeV/c are common (that’s a disaster). Individually tuning the first 2 cavities of each section permits tuning those oscillations down to ~0.2 MeV/c. My tunings differ from Study 2 by up to 20% in MV/m. The largest is only 5% above Study 2 values. HistoScope provides features that make it much more efficient to manually iterate tunes. A more accurate automatic tuning method is needed, as my manual tunes are clearly not optimal. I’m working on one.

5. TJR 01/21/2003Slide 5 Summary at End of Cooling Channel * Cuts: 140 < P < 260 MeV/c, |Dt| < 1.1 ns, Acc long = 15,000 cm mrad, Acc trans = 15,000 mm mrad

6. TJR 01/21/2003Slide 6 Conclusions RF Tuning is more important than the differences among the various absorber windows. The bellows windows used in these simulations should achieve cooling performance comparable to that in Study 2.

7. TJR 01/21/2003Slide 7 Backup Slides

8. TJR 01/21/2003Slide 8 Beam Characteristics at End of Cooling Channel (TolCooler207 is an old run)

9. TJR 01/21/2003Slide 9 (TolCooler207 is an old run)

10. TJR 01/21/2003Slide 10 (TolCooler207 is an old run)

11. TJR 01/21/2003Slide 11 (TolCooler207 is an old run)