QW Mayers2009Sim
Updated October 6, 2009
Triggered 1,000,000 elastic and inelastic primary events in Geant3 for different BFIL's. The Cerenkov bar for each case was located with a radial coverage X=319-337 cm, and the nominal BFIL factor is 1.04. The geometry version used was v2.11a.
Quick side note: even when generating "primary" events in the simulation, there are some events that minimally interact with the shileding wall aperture and lose energy. They "come from the target" but I do not consider them pure primary events. Therefore, I place a cut on the energy_in at the detector to eliminate these events. To determine this cut, I look at a plot of en_in and en_in versus en_o, which makes it clear what events interacted with a wall. The cut must be at least en_in>200. Typically, the cut is made higher, but this does not have a large impact on the results (at least within the uncertainty based on the statistcs). For the following cases, an energy cut of en_in>600 was used.
Here are some tables with the output from the simulation and calculated f, A_ep, A_pi, dA_pi/A_pi_stat (assuming 3.5 beam days, P = 0.85). The rates listed are for one octant. The average Q^2 of the inelastic events is ~0.022-0.025 GeV^2 (see example distribution for a 25% decrease in BFIL):
The equations used and an example calculation using the 17% BFIL decrease values can be found here: link.
BFIL decrease (%) BFIL factor ep yield (MHz) ep A*yield (ppm*MHz) pi yield (MHz) pi A*yield (ppm*MHz) % W>1232 (%) 15 0.8840 121.11 -30.77 8.51 -20.52 < 0.05 16 0.8800 120.89 -29.54 9.05 -21.07 < 0.05 17 0.8632 105.32 -24.85 12.08 -28.44 0.11 18 0.8528 96.80 -22.58 14.22 -32.94 0.23 19 0.8424 90.61 -20.74 16.05 -36.98 0.36 20 0.8320 84.57 -19.20 18.22 -41.70 0.60 25 0.7800 62.44 -13.41 25.02 -54.75 7.2 27 0.7590 59.93 -12.60 25.49 -54.84 16.1 28 0.7490 53.70 -11.32 25.00 -53.62 21.3 29 0.7384 53.30 -11.13 24.49 -52.04 28.3 30 0.7280 50.86 -10.46 23.51 -49.52 35.0 BFIL decrease (%) BFIL factor f_ep A*yield pi/ep |A_pi| (ppm) |A_ep| (ppm) |A_m| (ppm) dA_pi/A_pi (%) |dA_pi| (ppm) 15 0.8840 0.934 0.667 2.412 0.254 0.336 42.1 1.02 16 0.8800 0.930 0.714 2.329 0.244 0.331 41.0 0.96 17 0.8632 0.897 1.144 2.354 0.236 0.386 28.9 0.68 18 0.8528 0.872 1.459 2.316 0.236 0.425 24.2 0.56 19 0.8424 0.850 1.783 2.304 0.229 0.460 21.2 0.49 20 0.8320 0.823 2.171 2.289 0.227 0.504 18.4 0.42 25 0.7800 0.714 4.082 2.189 0.215 0.663 12.9 0.28 27 0.7590 0.702 4.352 2.151 0.210 0.671 12.8 0.27 28 0.7490 0.682 4.739 2.145 0.211 0.701 12.5 0.27 29 0.7384 0.686 4.677 2.134 0.209 0.691 12.8 0.27 30 0.7280 0.684 4.735 2.106 0.206 0.686 13.2 0.28