1. RF background generator in G4MICE Video conference 17/12 -03 Yagmur Torun Rikard Sandström Geneva University

2. Options There are several options available to the user to generate the RF background. Please see Yagmur's talk 3 Dec. Some of these are Fixed The user specifies a constant energy for the background electrons/photons. Flat Flat energy distribution User G4MICE reads the spectrum from histogram files (ordinary text format). Here the user can specify whether the entries should be interpreted as discrete, or flat (centered at that energy). In the latter case the bins must be equidistant.

3. Discrete spectrum Example of discrete spectrum (User) This spectrum was created by moving the RF background source inside the upstream TPG in order to avoid material effects. The option is User with energies 2, 4, 6, 8 MeV, each with a weight. The electrons initially from the background emitter are automatically painted red (emigrants) since the have high enough energy to escape the detector. Some high energy electrons reach the downstream TPG, and are thus green (vagabonds). RF electrons

4. Continous spectrum Example of continous spectrum This spectrum was created in a very similar way as in the previous slide. Energy steps High energy hits on the other detector (no cooling)

5. Discrete photon spectrum

6. Continous photon spectrum

7. New simulation Tracking now fixed, allowing low energy electrons to propagate correctly in fields. Bug in full simulation mode prevents using electrons onto absorbers right now, however: With 3000 MHz of RF electrons (proposal), 50 microsec open gate and previous similated photons/e = 3.54% you get 5310 gamma per open gate. This is used in DetectorsOnly mode shooting (all) onto the upstream TPG. Only one muon per open gate (no pileup)

8. No background, 100 mu Almost all electrons are confined (98%)

9. Most photons from entrance face Some photons from sides Reproducing old spectrum... From presentation 24 sept -03

10. Photon energy Should look like previous spectrum Shooting photons on the upstream TPG Specified 531000% Backscattered from GEMs & Hexaboard

11. Range of photons All photons go through face to face

12. Electron energy 165 electrons per open gate, 5 of these from muon Upstream TPG Downstream TPG

13. Range of electrons Upstream direction Downstream direction Many e's travel perpendicular to beam axis

14. Conclusion RF background simulation works and does not contradict previous results. With no background we had a ratio e/open gate = 4.78. With the given assumptions, this number is 164.53 in the TPG with RF photon background turned on. About one tenth of them go through the detector face to face. –Previously (24 Sept) I said 10-20 go through face to face. Many of the electrons enter and leave with a very large angle wrt beamline.

15. Future plans Should use electrons on absorbers ASAP. Higher statistics needed (when bug fixed). Use background generator in SciFi Recon and Analysis with MICE2ROOT and compare with no background (possible now). Late spring, should be able to do the same for TPG (Olena).

16. God Jul!