A new cylindrical photon-veto detector for the KOTO...
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A new cylindrical photon-veto detector for the KOTO experiment Osaka University Manabu Togawa for the KOTO collaboration - We installed a new photon-veto detector (Inner Barrel) in April 2016. - Suppress K L ->2π 0 background to be 1/3 - First physics run with the Inner Barrel at May-June. NCC MB CV CsI calorimeter CC03 OEV CC04 C LCV BCV HINEMOS K L γ γ ee γ γ FB NCC MB CV CsI calorimeter CC03 OEV CC04 CC LCV BCV HINEMOS K L γ ee γ γ γ Trapezoidal shape x 32 ~2013 2014 2015 2016 - Sandwich Calorimeter 5 mm-thick scinti. (MS resin) x 25 1 mm-thick lead plate x 24 Read out by WLS fiber (BCF92) τ~2.7 ns Fixed specification. Fiber attachment with company Due to uncured glue. Re-cure, re-production… Module construction Installed !! MB IB Looks K L ->π 0 νν event… :( Remove by increasing efficiency :) 2016 physics run (May - June) O K T ν ν s d Timing resolution evaluated by cosmic-ray 200 250 300 350 400 450 500 550 600 650 1 10 2 10 3 10 K L -> 2π 0 reconstruction by 4 γevent w/ MB&IB veto cut ModID MB_Outer : 0.308 ± 0.006(stat) MB_inner : 0.416 ± 0.004(stat) IB : 0.219 ± 0.008(stat) Timing resolution (ns) M KL (MeV) Black : Real data Blue : KL->3π 0 (MC) 13.5 X 0 13.5 + 5 X 0 IB Background from K L ->2π 0 ~3 m ~2 m Crack appears !! Alignment of support rings Installation of modules
Transcript of A new cylindrical photon-veto detector for the KOTO...
A new cylindrical photon-veto detector for the KOTO experiment
Osaka University Manabu Togawa for the KOTO collaboration
- We installed a new photon-veto detector (Inner Barrel) in April 2016.
- Suppress KL->2π0 background to be 1/3 - First physics run with the Inner Barrel at May-June.Background from KL0-> 2π0
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• CsI calorimeter (π0 -> 2γ) + Hermetic detectors (veto)
• Pencil beam -> can reconstruct decay vertex assuming π0 mass
FB NCC MB CVCsI calorimeter
CC03OEV
CC04 CC05 CC06 BHCV BHPV
LCVBCVHINEMOS
Saturday, April 20, 2013
KL γγ
30 GeV proton
Ni, Pt, Au target
Collimator
16 degree
20 m
10 m
γ γ
New detector : Inner Barrel detector
• 内層に同様の鉛-シンチサンドイッチカロリメータをインストール
• 13.5 X0（メインバレル）+ 5 X0（インナーバレル）
• EM反応に対して十分な厚み：BGを1/3に低減5
FB NCC MB CVCsI calorimeter
CC03OEV
CC04 CC05 CC06 BHCV BHPV
LCVBCVHINEMOS
Saturday, April 20, 2013
KLγ
30 GeV proton
Ni, Pt, Au target
Collimator
16 degree
20 m
γ
γ
γ
Trapezoidal shape x 32
Inner BarrelGluing WLS fibers
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Finished gluing 12000 WLS fibers (50 km) for 30.5 modules9
2013年終わり
紫外線硬化樹脂 NOA61
~2013
2014
2015
2016
- Sandwich Calorimeter 5 mm-thick scinti. (MS resin) x 25 1 mm-thick lead plate x 24 Read out by WLS fiber (BCF92) τ~2.7 ns
Fixed specification.
Fiber attachment with company
Due to uncured glue. Re-cure, re-production…
IB construction (4)
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lifted at both ends by a crane, rotated and mounted on the ring
Detector upgrade: IB
Module construction
Installed !!
MB
IB
Looks KL->π0νν event… :( Remove by increasing efficiency :)
2016 physics run (May - June)
OK Tν
νs
d
Timing resolution evaluated by cosmic-ray
200 250 300 350 400 450 500 550 600 6501
10
210
310
410
200 250 300 350 400 450 500 550 600 6501
10
210
310
KL -> 2π0 reconstruction by 4 γevent w/ MB&IB veto cut
Module&dependence&
ModID&
Timing&resolu+on&[ns]&
MB_Outer#:#0.308#±#0.006(stat)#MB_inner#:#0.416#±#0.004(stat)#IB#:#0.219#±#0.008(stat)#
Timing resolution (ns) MKL (MeV)
Black : Real data Blue : KL->3π0 (MC)
13.5 X0 13.5 + 5 X0IBBackground from
KL->2π0
~3 m
~2 m
Crack appears !!
Alignment of support rings
Installation of modules
