Beam direction and flux measured by MUMON K. Matsuoka (Kyoto) for the MUMON group Contents: 1.Beam stability (direction/flux) 2.Absolute  beam flux

Neutrino beam direction Measure ( ) beam direction by measuring muon profile center. (Another end is target) 1-mrad shift of the beam direction corresponds to 11.8-cm shift of the MUMON profile center. Requirement for MUMON: 3-cm=0.3mrad precision 2.5˚ Beam dump MUMON 295 km Target Horns p    118 m OTR Baffle

Basic Analysis method analysis has done by simple charge integration & 2D Gaussian fitting. for both online/offline analysis PedestalGate Silicon 80 mV for 3 x ppp wave form x 49 in some analysis, we also use total charge of 49 ch

Confirmation of Horn focusing 3 horns, 320 kA (shot# 47577), 2.16 x ppb, 6 bunch 1 st horn, 275 kA (shot# 47987), 2.10 x ppb, 6 bunch no horn, 0 kA (shot# 48704), 2.13 x ppb, 6 bunch peaksigmapeaksigma 1547 pC83 cm38.5 pC90 cm 467 pC95 cm13.2 pC104 cm 218 pC110 cm6.29 pC126 cm x2.1 x7.1

Stability of the beam direction Monitored the profile center obtained by the 2D Gaussian fit. During continuous 425 shots (Run: ) With 3 horns operation at 320 kA. Proton beam intensity (CT05): 2.15 x ppb x 6 bunches * 30-dB attenuators was used for the silicons.

Stability (fitted beam center) Chamber x RMS: 4.3 mmRMS: 3.0 mm Silicon x RMS: 1.9 mmRMS: 2.4 mm Silicon yChamber y Center values are different by ~1cm. Need check! (MUMON intrinsic fluctuation estimated by S/N is ***mm )

Stability (beam direction) (MUMON center)/(Dist.from target) No time dependent drift Beam direction was tuned well within 1 mrad. Monitor alignment should be checked. Further turning in Jan. Beam axis √ (x 2 + y 2 )

Stability (flux) incl. stability of beam+horn field+MUMON SiliconChamber RMS/Mean: 0.8%

Stability (flux) cont’d. CT normalized SiliconChamber RMS/Mean: 0.5% RMS/Mean: 0.50% 0.5% is same as the CT stability by Shibata-san stability of MUMON+(horn field) < 0.5% MUMON intrinsic fluctuation estimated by S/N is ***%

Stability (flux) incl. beam+horn field+MUMON No time dependent drift

Beam scan on the target Only horn-off data in Nov/Dec commissioning (1 st horn 273kA data in April/May commissioning) Scan w/ all horns will be in Jan/Feb. Opposite direction shift is expected. x target Proton beam were intended to shift in parallel. But angle change also existed

Beam scan on the target - Center position- MUMON alignment? Beam angle effect? (0.3mrad) Target alignment? SSEM18-19 alignment?

Beam scan on the target -Muon yield- Total Charge Peak charge Gap btw. Baffle and target? P beam  30mm  26mm baffle target Target center may be at -0.5~-1mm??

Absolute muon flux estimation Two methods in addition to the emulsion measurement A)Energy deposit calculation by MC.  Get the relation btw. muon flux and energy deposit in the detector B)Calibration by electron beam test Under study. Preliminary result is showing consistent result w/ A)

Estimation from MC energy deposit Energy deposit by all particles is summed up and divided by #muons Contrib. from  -rays generated outside detector and escape of  - rays generated inside detector are (automatically) taken into account E dep = 2420 MeV/(15266 muons) = keV/muon Ionization yield: Q = E dep / 3.6 eV x e 0 = =7.045 x 10 –3 pC/muon 2420 MeV Energy deposition in the silicon (MC) *Relying on estimation of  -ray contribution by Geant3. Bare Si measurement confirmed that the  -ray contribution is robust(~1% effect) against materials around.

Comparison w/ MC

Absolute muon beam flux Silicon (chamber) measurement is consistent w/ emulsion one. Muon flux measured by each detector at the center emulsion (10 4 /cm 2 ) Correction of the z- position diff. is applied. Cuts for emulsion analysis is applied (p > 0.05 GeV/c,  < x ppb [ 3 horns 320 kA ] IC data/MC: 0.87

Summary Horn focusing effect Beam direction Tuned within 1 mrad (and will be further tuned.) Less than 0.03mrad (rms) fluctuation Beam flux  <0.5% (RMS) fluctuation Target scan Horn-off data for target center determination Need more study to understand the obtained results Horn-on data will be taken in Jan./Feb. Absolute muon flux estimations and comparison w/ MC Agree with the emulsion measurement.

Supplement

Stability of the proton beam Run: Cont. 6-bunch operation Inc. monitor stability Stability of CT: 0.5% (Shibata-san’s talk) RMS: 0.1 mm RMS: 0.2 mm RMS/Mean: 0.9%

Uji electron beam test 6-coil CT Electronics calibration factor inc. AMP: (4.053±0.004) x 10 –3 pC/ADC Pedestal RMS: 17.9 (for 120 samples)  pC uncertainty IC Electronics calibration factor: (4.158±0.002) x 10 –2 pC/ADC

Energy loss comparison (Uji/T2K) Energy loss in the chamber (Ar + 2% N 2, 131 kPa, 34˚C) by MC Uji 100-MeV electron beam: keV/electron (av. of all particles; , e) T2K beam at the center: 4.755/4.824/4.443 keV/muon (1 st horn 0/220/273 kA)  ± keV/muon (av. of all particles; , e,  ) Uji beam T2K beam

A-1. Chamber calibration CT gain was calibrated by Suzuki-san ± (out/input charge) IC/CT from the Uji electron beam test Correction of energy loss diff. between the electron beam and the T2K muon beam (16%).  IC calibration factor: (4.80 ±0.25 ) x 10 3 muon/cm 2 /pC IC/CT = 128.0±0.2

A-2. Silicon calibration Si/IC ratio from high intensity beam data (horn off) ±0.09 Correction of the z-position difference (8%) Beam density at each position is different due to beam divergence.  Silicon calibration factor: 154 ±9 muon/cm 2 /pC

Absolute muon flux (chamber) CT efficiency by calibration: ±  CT factor: (4.019 ±0.003 ) x 10 7 particle/pC IC/CT (Uji): ±0.2 (Ar + 2% N 2, 130 kPa, 29.7˚C)  Uji IC factor: (3.140 ±0.006 ) x 10 5 electron/pC  (3.120 ±0.006 ) x kPa, 34˚C Energy loss in MC (Ar + 2% N 2, 131 kPa, 34˚C) Uji 100-MeV electron beam: keV/electron (av. of all particles; , e) T2K beam at the center: ±0.231 keV/muon (av. of all particles; , e,  )  T2K IC factor (“collected charge” to “muon flux” conversion): (2.70 ±0.14 ) x 10 5 muon/pC = (4.80 ±0.25 ) x 10 3 muon/cm 2 /pC

Absolute muon flux (silicon - Si/IC) T2K IC factor: (4.80 ±0.25 ) x 10 3 muon/cm 2 /pC Charge ratio at the center Si/IC in data (run , horn 0 kA): ±0.09 (–15 dB Att. is not calibrated, assuming ) Beam size:  x,y Si ±0.1, ±0.1,  x,y IC ±0.6, ±0.4 cm Muon flux ratio at the center of Si/IC plane in MC 1 st horn 0 kA: ±0.017 sta (  x,y Si 170 ±4, 166 ±4,  x,y IC 174 ±5, 177 ±5 cm) 1 st horn 220 kA: ±0.015 sta (  x,y Si 157 ±3, 162 ±3,  x,y IC 161 ±3, 182 ±5 cm) 1 st horn 273 kA: ±0.013 sta (  x,y Si 128 ±2, 125 ±2,  x,y IC 133 ±2, 139 ±2 cm)  ±0.018±0.013 sta  Si factor: 4.80 x 10 3 / (33.89 / 1.084) = 154 ±9 muon/cm 2 /pC

Absolute muon flux (silicon - dE/dx) MC estimation of energy deposit in the silicon plane at the center with 1 st horn 273 kA: E loss = GeV/(15266 muon) = keV/muon Ionization yield: Q = E loss / 3.6 eV x e 0 = x 10 –3 pC/muon  Si factor: muon/ pC

Comparison between Si and emulsion Muon flux ratio at the center of Si/emulsion plane in MC 1 st horn 0 kA: ±0.018 sta (  x,y Si 170 ±4, 166 ±4,  x,y IC 177 ±5, 183 ±5 cm) 1 st horn 220 kA: ±0.016 sta (  x,y Si 157 ±3, 162 ±3,  x,y IC 165 ±4, 188 ±5 cm) 1 st horn 273 kA: ±0.014 sta (  x,y Si 128 ±2, 125 ±2,  x,y IC 136 ±2, 145 ±2 cm)  ±0.032±0.014 sta Muon reduction rate at Si by the cut for the emulsion analysis (momentum > 0.05 GeV/c, angle < 0.3 rad) by MC 1 st horn 0 kA: momentum cut 0.024%, angle cut 2.1% 1 st horn 220 kA: momentum cut 0.026%, angle cut 3.4% 1 st horn 273 kA: momentum cut 0.052%, angle cut 3.6 ±1.2 sta %  3.65 ±1.5±1.2 sta %

Absolute flux (summary table) Silicon (Si/IC)Silicon (dE/dx)Emulsionjnubeam 10a 1 st horn 0 kA 1.04 ± ± ± st horn 220 kA 1.70 ± ± ± st horn 273 kA 2.30 ± ± ±0.02 Muon flux measured by each detector at the center emulsion (10 4 /cm 2 ) Silicon (Si/IC)Silicon (dE/dx)Emulsion 1 st horn 0 kA st horn 220 kA st horn 273 kA Muon flux ratio of each detector to MC