Beam MC activity A.K.Ichikawa for beam group For more details,

Summary of update in 09a,b,c 09a – This is almost equivalent to 07a except some bugs were fixed. Those bugs would not influence the neutrino flux iteslef. 09b – Mainly, geometry of baffle, target, 1st horn, dump and MUMON is updated. 09c – MUMON structures were included. – Energy deposit in the MUMON detector can be stored. – Emittance and Twiss parameters can be specified via card. – Neutrino tracking is discarded. – The density of the dump concrete was changed from 2.2 to 2.3g/cm3.

Comparison among different versions K. Matsuoka

MUMON A few bugs introduced in 2009 were found and fixed. Mainly in horn1. Magnetic field (proportional to 1/r) starts from r=2.7cm – Horn1 inner conductor Inner radius = 2.7cm, outer radius=3cm – Originally it starts from 3cm – Actually, something between them (skin depth > 5mm) – For MUMON, a few% effect K. Matsuoka

Muon flux at muon pit Spring commissioning (1 st horn only) Emulsion v.s. MC A.Ariga et. al. 273kA Data/MC= kA Data/MC=0.75 0kA Data/MC=0.57

horn2 and horn3 Geometry update update from conceptual shape to real shape Horn2 – outer conductor radius : 40 cm -> cm – B-field region (Z-length) : 200 cm ->195.7 cm Horn3 – outer conductor radius : 70 cm  65.5 cm – B-field region (Z-length) : 250 cm  cm H.Kubo Muon decreased by 3%, profile shape is same

Horn2&3 geometry update neutrino flux 09b new Far/Near less than 5% difference upto 5GeV

Parents of muons in muon pit -pions- H.Kubo. K.Matsuoka Horn off 1 st Horn 273kA All horns 320kA

Proton information Store primary beam information in a common block and MUMON or neutrino ntuple. – libneubeam/beaminfo.inc integer gipart : Primary generated particle ID real gpos0(3) : Generation point – common /gbeam/gipart, gpos0 Accumulate POT w/ a flat proton beam. Weight the muon profile w/ an arbitrary proton profile by using gpos0. We do not need to make many MC data sets of various proton beam profile. K. Matsuoka

new ND flux calculation algorithm current filling routine – SK : treated as a “point”. generated neutrino is always filled acceptance of SK for each decay is included in “norm”. – ND : repeat parent’s decay randomly (uniformly in CM) by N times (default 1,000). only neutrinos which have proper angle are filled. New method : fill ND ntuple just the same method as one of SK. 1.choose a detection point (x, y) randomly in the ND plane 2.calculate weight (acceptance) for this direction using parent 4-momentum  same method with SK ntuple. Motivation – In the current version, high-energy pions are multiply used. Events are not independent. Simple error couting results in underestimate. Status – Coding is almost done. Under check. H.Kubo

Remaining issues towards Dec.(Jan.) mass production Received requests from ND280 beam group Received a request from Hiro – To check new ND280 algorithm, want flux in both old and new algorithm Need to be done – final(?) check of new ND algorithm – final(?) check of mag. field inside conductor – correct ND280 position – Optimization of proton beam area two flat area? – check of Nicolas commitment and decide which should be stored for mass production version – Random seed control?