Status of KEK-E391a and Future Prospects on K L π 0 νν at KEK. GeiYoub Lim IPNS, KEK

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1 Status of KEK-E391a and Future Prospects on K L π 0 νν at KEK GeiYoub Lim IPNS, KEK

2 E391a Collaboration Joint Institute for Nuclear Research (Dubna), Russia High Energy Accelerator Research Organization, KEK, Japan Department of Physics, Kyoto University, Japan National Defense Academy of Japan, Japan Department of Physics, National Taiwan University, Taiwan Department of Physics, Osaka University, Japan Department of Physics, Pusan National University, Korea Research Center for Nuclear Physics, Osaka University, Japan Faculty of Science and Engineering, Saga University, Japan Department of Physics, University of Chicago, USA Department of Physics, Yamagata University, Japan

3 K L π 0 νν -A golden mode of Kaon decay Very clean in theoretical calculation Important in both of SM and New physics Difficult to measure Tiny branching ratio Three body decay with two neutrinos Neutral income, neutral outcome Really possible to measure? KEK-PS E391a aiming to answer

4 Current and future of experiment π ο e + e - γ π ο γγ KTeV result; Phys. Rev. D61 (2000) KTeV Result; Phys. Lett. B447(1999)

5 Clear single π 0 What shall we do? π 0 γγ for high sensitive measurement Confirm no other accompanying particle Perfect veto system Complete understand of background Based on data with help of M.C. A huge amount K L decays High intensity K L beam line, Large acceptance

6 E391a detector

7 Detection principle π 0 with high P T Pencil beam Narrow beam P T resolution single π 0 production (from neutron halo) Low energy free from hyperon decays Detector system in vacuum π 0 production (beam neutron) Minimize materials between decay region and detectors Perfect Veto system 4π coverage veto counters including beamline Double decay chamber Reject K L decay in front of fiducial region High detection efficiency Low detection threshold Low noise, Low counting rate, good timing information

8 Pencil beam

at target Λ by n with detector π by n with residual π by ngas with detector total 0.014~0.114 at CC- <0.

9 Beam Survey Very well collimated beam profile M.C. reproduced the data well M.C. study for beam related B.G. estimation Safe at the E391a sensitivity Large ambiguity waiting data Λ at C6 γ Source No absorber Λ at target Λ by n with detector π by n with residual π by ngas with detector total 0.014~0.114 at CC- < Event#/E391a- Neutron No absorber Sensitivity gamma neutron < 0.11 < ~

10 Detector Construction Three self-standing sections Parallel preparation Match to beam time on Feb Down-stream section Electromagnetic calorimeter Up-stream section Front barrel first decay chamber Middle section Central barrel main decay chamber (Fiducial region)

11 Electromagnetic calorimeter CsI crystals 496 of Type I (70X70X300) 24 of Type II (50X50X500) 56 of Type III (deformed X 300) CC03 (Beam counter (W/Scin.) Corner Counter (Pb/Scin.) Charged Veto Fabricated at summer 2002 Beam test at Oct.-Dec (Engineering run)

DAQ using self-trigger of CsI Same scheme of real run Tuning

Cosmic test during stacking Punch-through muon Two gammas

Engineering run Gain Time (MeV/pQ) delay, ns KTeV CsI KEK

12 DAQ using self-trigger of CsI Same scheme of real run Tuning / feed-back CsI calibration Cosmic test in vacuum chamber Cosmic test during stacking Punch-through muon Two gammas from single p0 Multi-gamma decay (Kpi2, Kpi3) K L decay data Engineering run Gain Time (MeV/pQ) delay, ns KTeV CsI KEK CsI corner CsI Develop on-line/off-line software Crystal, HV, volts ID

13 Engineering run DAQ using self-trigger of CsI Same scheme of real run Tuning / feed-back CsI calibration Cosmic test in vacuum chamber Cosmic test during stacking Punch-through muon Two gammas from single p0 Multi-gamma decay (Kpi2, Kpi3) K L decay data Develop on-line/off-line software 3 π0 σmπ 0 Θ Consistent result for different σm position of π 0 π 0 0'. CsI generating target Vertex along the beam direction 0'.

Evacuation test Evacuate a large size detector Cooling system Temperature

dependency of Light Yield Find operating condition PMT temp (0C) MeV/pC Leakage

to PMT Normalized by the engineering data Cosmic Peak position dp/dt = 0.

14 Evacuation test Evacuate a large size detector Cooling system Temperature increasing at PMT. Temp. dependency of Light Yield Find operating condition PMT temp (0C) MeV/pC Leakage He leak gauge Outgas larger than leakage expected values Apply H.V. to PMT Normalized by the engineering data Cosmic Peak position dp/dt = 0.22 Pa/hr 10-1 Outgas Pa m3/s CsI temp (0C) Yield t h g Li / 0C % 3 : -1. Cosmic 10-2 Peak width Operating time (min.) Operating time (hr)

Upstream fabrication 16 modules of front barrel

, 2003 Beam Counter (CC02) 59 layers Pb/Scin.

readout 10-20 p.e. per MeV deposit Shashlyk type

readout 9-11 p.e. per MeV Assembling into barrel

15 Upstream fabrication 16 modules of front barrel 5, Sep., 2003 Beam Counter (CC02) 59 layers Pb/Scin. (~15 X0) WLS fiber readout p.e. per MeV deposit Shashlyk type Pb/Scin (~16 X0) WLS fiber readout 9-11 p.e. per MeV Assembling into barrel Without any gap between modules Assemble CC02 together Finished at last week Evacuation test will be continued y r e V! y r a n i m i l e r p

2003/2/14 2003/2/28 2003/3/14 2003/3/28 2003/4/11 2003/4/25 2003/5/9 2003/5/23 2003/6/6 2003/6/20 2003/7/4 2003/7/18 2003/8/1 2003/8/15 2003/8/29

(~14 X0) WLS fiber readout (double side) Same principle as the front barrel Longer twice Rigid structure Different assembling method Schedule Module

16 2003/2/ /2/ /3/ /3/ /4/ /4/ /5/9 2003/5/ /6/6 2003/6/ /7/4 2003/7/ /8/1 2003/8/ /8/ /9/ /9/ /10/ /10/24 Middle Section Fabrication 32 modules of Pb/Scin. 45 layers Pb/Scin. (~14 X0) WLS fiber readout (double side) Same principle as the front barrel Longer twice Rigid structure Different assembling method Schedule Module fabrication : End of Sep Vacuum chamber : End of Oct Assembling :Nov.-Dec Glued plates Weeks : /: 08 Num ber of Plates 4/: 0$9, Glued P lates

17 Schedule FB assembling CB fabrication Check Membrane Downstream vacuum test Cosmic and evacuate test for the upstream Middle section fabrication A/D Card upgrade ADC Replacement CV PMT install CB assembling Moving downstream Additional Cabling BCV Membrane Unite three sections BA and CC05 installation Beam Evacuate system Start data taking CC04/CC05 Fabrication CC04 Installation Cosmic test Aug. Sep. Oct. Nov. Dec. Jan. Feb.

Accelerator parameters 400MeV Linac Peak Current ; 50mA Pulse Length ; 0.

18 J-PAPC Japan Proton Accelerator Research Complex Newly constructing high intensity proton synchrotron at Tokai in Japan Accelerator parameters 400MeV Linac Peak Current ; 50mA Pulse Length ; 0.5msec Repetition Rate ; 50Hz 3GeV RCS Average Current ; 0.333mA Repetition Rate ; 25Hz Beam Power ; 1MW 50GeV MR Average Current ; 0.015mA Repetition Rate ; 0.3Hz Beam Power ; 0.75MW Start an experiment from 2008 KAMIOKA Diving Spots TOKYO KEK J-PARC NARITA Clamming Place

K L π 0 νν at the J-PARC Large Number of K L Decay Three orders larger K L flux Experience at KEK-PS Fast Electronics High counting rates Optimization of beam line K L

19 K L π 0 νν at the J-PARC Large Number of K L Decay Three orders larger K L flux Experience at KEK-PS Fast Electronics High counting rates Optimization of beam line K L /n/γ ratio, Λ production Detector Up-grade Calorimeter fast response Granularity Veto system Detection efficiency Become thicker (?) T.Inagaki CP Violation in K (1998)

20 Realistic approach Ultimate goal ( > 100 SM events) -- Finalized beam line/detector setup Boundary condition -- Delays in schedule Alternating option SM sensitivity -- One more step -- Share target station -- Match to J-PARC commissioning

21 Summary K L π 0 νν decay Golden mode in the both of the SM and New physics Become more important with improved measurements in future KEK-PS E391a The first dedicated experiment for the K L π 0 νν Detector is constructed on schedule for Feb Aiming to 3X10-10 S.E.S. Significant step to the precise measurement Smooth extension to the J-PARC Three orders higher K L flux Great advantage for the rare decay Many problems we have to solve Step-by-step approach Gradual up-grade guided by the E391a results Ultimate measurement for the decay

PoS(KAON09)023. Beam Hole Photon Veto For J-PARC K O TO experiment. Yosuke Maeda Kyoto University

PoS(KAON09)023. Beam Hole Photon Veto For J-PARC K O TO experiment. Yosuke Maeda Kyoto University Beam Hole Photon Veto For J-PARC K O TO experiment Kyoto University E-mail: maeda_y@scphys.kyoto-u.ac.jp The Beam Hole Photon Veto counter (BHPV) for the J-PARC K O TO experiment was designed by MC simulation.