History: Luminosity Dependence

We observe that the ratio of neutrons to protons identified by the neutron detector changes with luminosity. This was tracked to a decrease in the normalized (after corrected for electronic and DAQ deadtime, and an estimate of the tracking efficiency) proton yield as the luminosity increased, while the neutron yield is largely insensitive.

A few definitions:

1. Events were selected that had an electron in BigBite with an amplitude in the preshower greater than 450 (B.ts.ps.e>450), and a calculated W in the range 0.8<W<1.15 GeV.
2. The missing momentum between the "cluster" in the neutron detector and the virtual photon were in the range |Ppar-q|<250 MeV/c, |Pperp|<150 MeV/c.
3. Protons were identified as clusters with geometrically matching veto hits in BOTH v1 and v2 within +/-10ns of the cluster's time.
4. Neutrons were clusters WITHOUT a veto hit within 3 veto bars in BOTH v1 and v2, in the time range -110ns to +10ns around the cluster's time.

During kin4, we took runs on the Hydrogen- and Nitrogen-filled reference cell at a couple of different beam currents, and (accidentally) at two different pressures for the Nitrogen cell. The runs used for this study and their conditions are in the table below:

Run Range	Beam Current	Target Pressure(psi)	A	Z	N(neutrons)	N(protons)	LT(elect.)	LT(DAQ)	Tracking Eff.	Q
4425-4427	2.55	149	1	1	1062	12824	0.933	0.931	0.934	5.67
4596	5.8	149	1	1	260	2082	0.785	0.744	0.646	2.38
4597	4.85	149	1	1	226	2101	0.811	0.840	0.767	1.67
4583	1.95	24	14	7	60	260	0.916	0.954	0.958	0.513
4585	1.95	149	14	7	981	3097	0.846	0.839	0.872	1.76