Horns, Hadron production etc. (from hadron production to neutrino beam) A.K.Ichikawa KEK 200/9/26 Study on horns Changing -beam energy Hadron production

Study on horns

Brief comment on the horn design status Till now, in the beam MC simulation, horns proposed in BNL-E889 was used. 2.2m D in = 1.9cm , I=250kA Sapphire target (Al 2 O 3,  =4g/cm 3 ) D=0.64 cm, L=45cm 1st horn c.f. K2K D in =3.0cm , I=250kA In addition, heat load from radiation Need realistic design work

 production –Model- Momentum and angle of   =const.+const./ MARS 50GeV, graphite  = /p MARS 50GeV :  = /p 30GeV :  = /p GFLUKA+GCALOR 50GeV :  = /p 30GeV :  = /p FLUKA GeV :  = /p 30GeV :  = /p

Momentum region of  ’s w/ BNL-type horn, 2.5°OAB  ’s contributing E <1.2GeV >1.5GeV/c >1.7GeV/c

4.4m W/ fixed current, r x 2 L x 2, Wx2 to obtain same optics. 2.2m D in = 1.8cm  D in = 3.6cm  Scaling laws

BNL-type horn1 K2K horn1 OAB1 o WBB w/ K2K horns D in = 1.8cm  D in = 3cm 

1m Inner conductor 4.6cm  I = 250 kA 1.7GeV 2GeV 2.5GeV 3GeV 4m Target in the horn 1m 10m 4m Target outside the horn

6cm , I=250kA 22cm , I=500kA 2.5m 1.4m 1m 36kA/cm K2K 35kA/cm 2 66cm  One idea for ‘1 st horn’ Till now, only 60% flux have been achieved…..

~3m The other idea for ‘1 st horn’ ~250kA, D in ~4cm  ~500kA

Heat Load from Radiation Graphite  =1.8g/cm 3 Water t=5mm Air t=6mm Inner cond. Al t=4mm In total, 34kJ/3.3E14 protons = Hz cf. K2K heat load in the target from the current = 1.4 kW (surface area ~x 7) In the graphite target, 64kJ/3.3E14 protons in total 30mm  60mm   t~14 o Z R Z R

Strategy to change peak energy

Change the neutrino beam energy Side View Top view To SK/HK OAB 2° OAB3° Decay Volume Unofficial

Dipole magnet gap 1m×1m×1m One method is changing the beam axis. The other…. OAB+Bending Magnet Oyabu’s talk

Hadron production model

jnubeam : neutrino beam simulation code developed from K2K code DV shape : incorporate actual shape target & horns : still BNL-type. calculation of -flux at SK for all decays by weighting Hadron production model 1. Models built-in Geant3. e.g. GFLUKA.. 2. Various models using Input via stdout | stdin. > MARS | jnubeam > FLUKA2000 | jnubeam

GFLUKA MARS FLUKA2000 OAB2.5 o E p =50GeV Graphite 0.74cm  45cm

Comparison of different proton energy and different OAB2.5 o 50 GeV (10 21 POT) 30 GeV (10 21 POT) 30 GeV (10 21 x 5/3POT) GFLUKA MARS FLUKA Absolute flux (E <1.5GeV) x10 7 /cm 2 /yr e #( e)/#(  E <1.5GeV) 50 GeV30 GeV GFLUKA1.14%0.87% MARS0.90%0.86% FLUKA %0.83% (Target is graphite but the dimension is BNL-type.)

Comparison of different proton energy and different OAB2.5 o 50 GeV30 GeV#30 GeV/#50GeV GFLUKA63%57% - 9.5% MARS66%61%  7.6% FLUKA200064%59%  7.8% NC #NC/#CC(E <1.5GeV) High Energy tail #(E >1.5GeV)/#(E <1.5GeV) 50 GeV30 GeV#30GeV/#50GeV GFLUKA9.6%7.6%  21% MARS11.5%9.5%  17% FLUKA %8.8%  18%

Effects on SK observable MARS 50 GeV !!!! Graphite 45cm !!!!!

MARS 30 GeV !!!! Graphite 45cm !!!!!

P beam =5~120 GeV/c From R.Raja, NUFACT02

Summary or discussion item Horns : realistic design gathering ideas Changing the beam energy OAB vs OAB+bending Hadron production MIPP (30 GeV vs 50 GeV)

Supplement

Types for the 1 st horn (a) (b) (c) (d) MINOS K2K, CERN, BNL (2nd horn) (  -factory)

Beam Direction For both SK and possible HK. Decay pipe

Event rate at SK MARS 50GeV !!!Graphite 45cm target!!!