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