K 20

1 e, e K + 2000 2005 JLab e, e K + Λ K + 2 K + Missing Mass E/E 10 4 JLab 1 e, e K + Λ K, π π +, K + Λ Λ Σ 0 Mass Mass 2000 E89-009 e, e K + 12 Λ B 750 kev FWHM Missing Mass e, e K + background K + 1.5 MeV/C FWHM 2005 E01-011 background tilt K + K + HKS background 2009 e, e K + Λ E05-115 A 6 A 50 1 background HES HES tilt S/N HES Splitter K + π + proton background E01-011 π + /K + Aerogel Cherenkov AC K + /p Water Cherenkov WC AC Aerogel 1.05 WC wavelength shifter Amino-G salt 50 mg/l : 1.33 WC 1 40 K + /p proton rejection WC 2 layer 95 layer 98 proton rejection 2 layer 4 10 4 proton survival ratio JLab 60 Co γ Amino-G salt radiation damage Amino-G salt WC Cherenkov UVT

2 UV-PMT WC electron beam number of photoelectron : NPE 75 simulation WC K+/p layer 98 proton rejection K + over kill ratio 2.7 WC WC layer 98 proton rejection K + over kill ratio 1 layer 2.8 2 layer 5.6

i 1 1 1.1 Λ................................... 1 1.2................................... 1 1.3 e, e K + Λ........................ 2 1.4......................................... 3 2 e, e K + 5 2.1 e, e K +...................... 5 2.2 e,e K +........................... 8 2.2.1 CEBAF............................... 8 2.2.2 E89-009 2000................. 8 2.2.3 E01-011 2005................. 10 3 E05-115 13 3.1 E05-115............................ 13 3.2 E05-115............................... 13 3.2.1 HES tilt.............. 14 3.2.2 HES................................... 17 3.3 HKS K +..................................... 19 3.3.1 K + HKS...................... 19 3.3.2 HKS Drift Chamber (HDC)............................ 20 3.3.3 TOF Time of Flight counter HTOF.................... 22 3.3.4 Aerogel Cherenkov AC......................... 22 3.3.5 Water Cherenkov WC......................... 22 3.3.6 Lucite Cherenkov LC......................... 22 4 K + 23 4.1........................................ 24 4.2 background singles rate................................. 24 4.2.1 singles rate..................................... 25 4.2.2 Kaon Particle ID.................................. 25 4.3................................... 25 4.3.1.................................. 27 4.3.2.................................. 28 4.4 E05-115 Water Cherenkov............. 29

ii 5 K + /p Water Cherenkov 31 5.1 Cherenkov.................................. 31 5.2 Cherenkov.................................. 32 5.2.1............................ 32 5.2.2....................................... 34 5.2.3..................................... 34 5.2.4 PMT.............................. 34 5.3 Water Cherenkov.................... 38 5.3.1 PMT.......................... 38 5.4 WC.............. 40 5.4.1 Hyper Cherenkov Simulator HYCS. 40 5.5................................ 42 5.5.1................................... 42 5.5.2...................................... 42 5.6 electron beam...................... 47 5.6.1..................................... 47 5.7............................................ 49 6 E05-115 51 6.1 Water Cherenkov............ 51 6.2 WC............................................. 52 6.2.1 E05-115................. 52 6.2.2 simulation WC K + /p.. 52 6.3............................................ 56 7 57 7.1 Water Cherenkov.............................. 57 7.2............................... 59 7.3......................................... 60 A 63 A.1............................ 63 A.2 PMT..................................... 63 A.3.......................................... 64 B WC (Water Cherenkov counter) 67 B.1 Number of Photoelectron............................... 67 B.1.1....................... 67 B.1.2......................... 68

iii 1.1 12 C..... 2 2.1 p e, e K + Λ............................... 6 2.2 p γ, K + Λ E γ......................... 6 2.3 12 C e,e K + 12 Λ B Λ K+.. 7 2.4 virtual photon flux........................ 7 2.5 CEBAF...................................... 8 2.6 E89-009 12 C e, e K + 12 Λ B.............. 9 2.7 E01-011 setup............................... 10 2.8 E01-011 12 C e, e K + 12 Λ B............ 11 3.1 E05-115 setup................................. 14 3.2... 15 3.3 virtual photon........................ 16 3.4 EHODO..................................... 19 3.5 HKS................................... 20 4.1 WC AC π + K + proton Cherenkov number of photoelectron................................. 23 4.2 Cherenkov........ 26 4.3 WC.................. 26 4.4 WC1 WC2 run number 56000 61000 1 [11]...................................... 27 4.5 Amino-G salt........................................ 28 4.6 E01-011 WC....................... 28 4.7............................. 29 5.1 Cherenkov................................... 32 5.2....................... 33 5.3.... 33 5.4...................... 35 5.5............................ 36 5.6........................................ 36 5.7 PMT.................................. 37

iv 5.8 Water Cherenkov...................... 38 5.9................................... 39 5.10 O -................ 40 5.11 µ electron Pure Water n = 1.33 NPE.................................. 41 5.12................................ 42 5.13 NPE......................................... 43 5.14 NPE............................. 44 5.15 NPE......................... 45 5.16 NPE + + UV-PMT......................................... 46 5.17 + + UV-PMT................................ 46 5.18 electron beam NPE............................ 48 6.1 Geant 4.......................... 51 6.2 simulation WC.......... 53 6.3 NPE threshold cut K + proton survival ratio......... 54 6.4 simulation WC 2 segment 55 6.5 segment K + survival rario................... 56 7.1............................... 58 A.1........................... 63 A.2 PMT.................................. 64 A.3 PMT................................ 65 A.4 PMT................................. 65 A.5................................ 65 A.6.................................... 66 A.7................................. 66 B.1 Water Cherenkov Counter.................................. 67

v 2.1 CEBAF....................................... 9 2.2 E01-011................................... 11 3.1 E05-115................................... 13 3.2 tilt....................................... 14 3.3 Enge HES................................... 16 3.4 HES EQ1 EQ2 ED........ 16 3.5 Splitter.............................. 17 3.6 EDC...................................... 18 3.7 EHOD..................................... 18 3.8 HKS......................................... 19 3.9 HKS KQ1 KQ2 KD....... 20 3.10 HKS.............................. 21 4.1 Cherenkov...................... 24 4.2 E05-115 target sigles rate...................... 25 5.1 NPE....................................... 34 5.2 K + /p Water Cherenkov............................................. 35 5.3 Water Cherenkov........ 39 5.4................................... 40 5.5 HYCS simulation NPE..... 41 5.6 NPE............................. 43 5.7 NPE..................... 47 6.1 ϵ det............... 52 6.2 K + proton NPE..... 52 6.3 simulation K + NPE peak 1 layer K + kill ratio......... 54 B.1........................... 68 B.2 NPE...................... 68

vi

1 1 1.1 Λ u, d [uud] [udd] s s 1 Λ[uds] Σ [dds] Σ 0 [uds] Σ + [uus] 2 Ξ [dss] Ξ 0 [uss] s Λ 1.2 Λ 1952 1960 BNL Λ 1970 BNL CERN K K, π Λ p Λ 1.1 K π +, K + 1.1 Λ π +, K + K, π K π + Li Ca Λ 1.5 2 MeV FWHM 1990 K + SKS KEK KEK-PS K6 SKS π +,K +

2 1 1.1: 12 C Li B C O V Y Pb 1.3 e, e K + Λ e, e K + γ + p K + + Λ Λ K + 2.1 K + e, e K + 100 nb/sr Λ e K + 1990 JLab e, e K + 1. 1 1 beam 2 π +, K + K, π 2.1 2. 400 MeV/c 3. Λ π +, K + K, π Λ e, e K + Λ

1.4. 3 π +, K + K, π 4. Λ Λ Σ 0 Mass (e, e K + ) 1.4 e, e K + JLab 2000 E89-009 2005 e, e K + K + HKS tilt E01-011 K + Water Cherenkov WC wavelenth shifter Amino-G salt radiation damage E05-115 E05-115 Λ HES E05-115 WC Amino-G salt WC number of photoelectron : NPE K + /p e, e K + 2 E05-115 3 Water Cherenkov 4

5 2 e, e K + 2 e, e K + e, e K + E05-115 2.1 e, e K + e, e K + 2.1 e + p e + Λ + K + (2.1) electro-production d 3 { σ dσt = Γ + ϵ dσ L dσ P + ϵ L cos 2ϕ K + 2ϵ L (1 + ϵ) dσ } I cos ϕ K de e dω e dω K dω K dω K dω K dω K E γ (2.2) α E e Γ = 2π 2 Q 2 (α : ) (2.3) 1 ϵ E e ϵ = {1 + q 2 Q 2 tan2 ( θ } 1 e 2 ) (2.4) ϵ L = ω + Q2 ω 2 ϵ (2.5) E γ = ω + q2 2m p (2.6) q = p e p e ω = E e E e (2.7) q = (q, ω) Q 2 = q 2 > 0 [2][3] 2.1 Ω e Ω K + K + Γ virtual photon flux ϵ ϵ L virtual photon ω T ω L ω P ω I ϕ K + Λ K + m p 2.3 E γ proton-photon virtual photon p γ,k + Λ E γ 2.2 E γ 1.5 GeV/c Baryon Mass = 1.92 GeV E e = 2.5 GeV/c E γ = 1.5 GeV/c DWIA 12 C e,e K + 12 Λ B Λ K+ 2.3 virtual photon flux 2.4 virtual photon K +

6 2 e, e K + 2.1: p e, e K + Λ γ γ p, K + Λ 2.2: p γ, K + Λ E γ Baryon Mass, W GeV [7] ω = 1.5 GeV W = 1.92 GeV

2.1. e, e K + 7 (e,e K + ) kaon angular distribution, harm. osci, DWIA Ground state of 12 ΛB Hypernuclei Total (1 - +2 - ) E e =2.5 GeV E e =1.0 GeV θ e =3.5 deg. Spin-flip (2 - ) Spin-nonflip (1 - ) 2.3: 12 C e,e K + 12 Λ B Λ K+ [15] 2.4: virtual photon flux [15] virtual photon flux virtual photon

8 2 e, e K + 2.2 e,e K + e, e K + 2000 E89-009 2005 E01-011 JLab JLab Continuos Electron Beam Accelerator Facility CEBAF 2.2.1 CEBAF e,e K + Λ e,e K + 100 nb/sr K,π 10 mb/sr π +,K + 10 µb/sr µa e,e K + K + duty factor 100 beam size 100 µm FWHM beam energy E/E 10 4 JLab CEBAF CEBAF 2.5 2 0.6 GeV 5 6 GeV A B C 3 499 MHz 499 MHz 2 ns 2.1 0.6 GeV linac (20 cryomodules) 1497 MHz 67 MeV injector (2 1/4 cryomodules) 1497 MHz RF separators 499 MHz A B C 2.5: CEBAF 2.2.2 E89-009 2000 2000 JLab Hall C e, e K + Λ [5][6] E89-009 Λ K + Hall C Shrot Orbit Spectrometer SOS Enge Split-Pole Spectrometer Enge

2.2. e,e K + 9 Maximum Beam Energy Maximum Beam Intensity Beam Size Beam Energy Spread Beam Bunch 6 GeV 200 µa / Hall 100 µm FWHM E / E 1 10 4 2 ns 499 MHz 2.1: CEBAF 2.6: E89-009 12 C e, e K + 12 Λ B [5]

10 2 e, e K + 12 Λ B 2.6 Λ S 1/2 750 kev FWHM [5] e, e K + SOS K + p/p 4.0 10 4 background - Mϕller 2005 2.2.3 E01-011 2005 2005 E01-011 [11] K + HKS tilt 2.7 2.2 2.7: E01-011 setup

2.2. e,e K + 11 Beam Energy 1.8 GeV Virtual Photon Energy 1.5 GeV e Momentum Acceptance 0.35 ± 0.15 GeV/c e Solid Angle 5 msr Enge Momentum Resolution p/p 4.0 10 4 K + Momentum Acceptance 1.2 ± 0.15 GeV/c K + Solid Angle 16 msr HKS Momentum Resolution p/p 2.0 10 4 2.2: E01-011 tilt background E01-011 12 Λ B 2.8 Λ S 1/2 490 kev FWHM E89-009 760 kev FWHM [11] E01-011 HKS K + JLab Hall C Enge 2.8: E01-011 12 C e, e K + 12 Λ B [11]

13 3 E05-115 E05-115 setup K + 3.1 E05-115 e, e K + 12 C 28 Si 6 Li 7 Li 10 B 11 B 40 Ca 52 Cr 89 Y Λ Core + Λ beyond p - shell ΛN - ls splitting 28 Si 40 Ca 52 Cr 89 Y 3.2 E05-115 3.1 E05-115 3.1 Splitter target HES K + HKS Beam Energy 2.5 GeV Virtual Photon Energy 1.5 GeV e Momentum Acceptance 1.0 ± 0.15 GeV/c e Solid Angle 10 msr HES Momentum Resolution p/p 2.0 10 4 K + Momentum Acceptance 1.2 ± 0.15 GeV/c K + Solid Angle 8 msr HKS Momentum Resolution p/p 2.0 10 4 3.1: E05-115

14 3 E05-115 3.1: E05-115 setup 3.2.1 HES tilt HES Virtual Photon Mϕller background 3.2 1 tilt tilt 3.2 Virtual Photon Mϕller background tilt Splitter K + background Enge 7.75 background 250 background 1/200 3.2 tilt HES tilt tilt method Beam current target thicness rate E89-009 without 0.6 µa 22 mg/cm 2 200 MHz E01-011 with 30 µa 100 mg/cm 2 1 MHz 3.2: tilt tilt 250 1/200 tilt

3.2. E05-115 15 HES tilt tilt background virtual photon Mϕller background S/N HES [15] 3.3 Enge HES 3.2 x, y z virtual photon Mϕller tilt Enge HES background HES central momentum Enge 0.35 GeV/c HES 1.0 GeV/c beam energy 1.8 GeV 2.5 GeV 3.2 background ϕller virtual photon 3.3 beam energy 3.2 HES Enge 2 3.3 tilt HES 8 [15] 3.2: x, y virtual photon Mϕller Enge HES [15] tilt background

16 3 E05-115 3.3: virtual photon [15] beam energy = 2.5 GeV central momentum = 1.0 GeV/c beam energy = 1.8 GeV central momentum = 0.35 GeV/c 3.2 background Mϕller Enge HES Configuration Split Pole Q-Q-D and horizontal 50 deg bend e momentum Acceptance 0.35 ± 0.15 GeV/c 1.0 ± 0.15 GeV/c e Solid Angle 5 msr 10 msr Momentum Resolution p/p 4.0 10 4 2.0 10 4 3.3: Enge HES EQ1 Pole length EQ1 Maximum Field Gradient EQ1 Bore Diameter EQ2 Pole length EQ2 Maximum Field Gradient EQ2 Bore Diameter Maximum Field Strength Gap Bending Angle Total Weight 60 cm 7.8 T/m 10 cm 50 cm 5.0 T/m 12.5 cm 1.64 T 19.4 cm 50 deg 38.5 t 3.4: HES EQ1 EQ2 ED

3.2. E05-115 17 Maximum Field Strength 1.65 T Gap 19 cm 1.0 GeV/c e Bending Angle 30.64 deg Total Weight 31.7 t 3.5: Splitter Splitter Splitter K + HKS HES 3.5 HES HKS [15] 3.2.2 HES HES 2 EDC1 EDC2 EHODO HES EDC1 EDC2 3.6 EDC1 E01-011 EDC2 E01-011 HDC1 HKS Drift Chamber HES Hodoscope EHODO EHODO PMT 3.7 3.4 2 layer 29 segment segment PMT

18 3 E05-115 EDC1 Sensitive area Layer Distance between Layers Cell size Resolution 100 cm 12 cm 30 cm xx, uu 30 deg, xx, vv -30 deg, xx 7.5 cm 1.0 cm Position Resolution horizontal ; x σ = 86 µm Position Resolution vertical ; y σ = 210 µm Position Resolution horizontal ; x σ = 0.7 mrad Angle Resolution vertical ; y σ = 2.8 mrad EDC2 Sensitive area Layer Resolution 120 cm 30 cm 14 cm xx, uu 30 deg, xx, vv -30 deg, xx 5mm drift distance, σ = 150 µm Position Resolution horizontal ; x σ = 162 µm Position Resolution vertical ; y σ = 163 µm Angle Resolution horizontal ; x σ = 0.33 mrad Angle Resolution vertical ; y σ = 0.33 mrad 3.6: EDC name sensitive area [cm] construction EHOD 1 117 30 1 3 W cm 29 segments PMT : HAMAMATSU H6612 EHOD 2 117 30 1 3 W cm 29 segments PMT : HAMAMATSU H6612 3.7: EHODO

3.3. HKS K + 19 3.4: EHODO size 117 30 1 cm 5 cm 1 cm 29 segment 3.3 HKS K + 3.3.1 K + HKS HKS E01-011 E89-009 background HKS Q-Q-D 3.8 HKS 3.9 Configuration K + Momentum Acceptance K + Solid Angle Momentum Resolution K + Path length Q-Q-D 1.2 ± 0.15 GeV/c 8 msr 2.0 10 4 10 m 3.8: HKS HKS 3.5 E01-011 setup HDC1 HDC2 TOF Time Of Flight HTOF 1X 1Y e + π + rejection Aerogel Cherenkov AC TOF HTOF 2X proton rejection Water Cherenkov WC proton rejection TOF Lucite Cherenkov LC

20 3 E05-115 KQ1 Pole length KQ1 Maximum Field Gradient KQ1 Bore Diameter KQ2 Pole length KQ2 Maximum Field Gradient KQ2 Bore Diameter Maximum Field Strength Gap Bending Angle Radius 84 cm -5.8 T/m 13 cm 60 cm 3.4 T/m 12 cm 1.53 T 20 cm 70 deg 325 cm 3.9: HKS KQ1 KQ2 KD 3.10 HKS 3.5: HKS beam HDC 1, 2 HTOF 1 AC 1, 2, 3 HTOF 2 WC 1, 2 LC 3.3.2 HKS Drift Chamber (HDC) K + HDC 1 2 HDC 2 HDC 1 2 3.10

3.3. HKS K + 21 name sensitive area [cm] construction Drift Chamber HDC1 120 30 14 xx, uu +30 deg, vv -30 deg 5mm drift distance, σ = 150 µm HDC2 120 30 14 xx, uu +30 deg, vv -30 deg 5mm drift distance, σ = 150 µm TOF counter HTOF1X 125 30 2 7.5 W 17 segments PMT ; HAMAMATSU H1949 2 inch HTOF1Y 125 30 2 3.5 W 9 segments PMT ; HAMAMATSU H1949 2 inch HTOF2X 170 35 2 9.5 W 18 segments PMT ; HAMAMATSU H1949 2 inch Aerogel Cherenkov n = 1.05 Silica Aerogel AC1 169 46 31 20 W 7 segments PMT ; photonics 14 5 tube AC2 169 46 31 20 W 7 segments PMT ; photonics 14 5 tube AC3 169 46 31 20 W 7 segments PMT ; photonics 14 5 tube Water Cherenkov n = 1.33 Water WC1 187.2 35 8 15.6 W 12 segments PMT ; HAMAMATSU H7195 or H7195UV 2 inch WC2 187.2 35 8 15.6 W 12 segments PMT ; HAMAMATSU H7195 or H7195 UV 2 inch Lucite Cherenkov n = 1.45 Lucite LC 189 35 8 13.5 W 13 segments PMT ; photonics 3 tube 3.10: HKS

22 3 E05-115 3.3.3 TOF Time of Flight counter HTOF HTOF HKS π + K + proton Particle ID Identification HTOF off line Particle ID 1X 2X 1.5 m KEK-PS T1 HTOF 77 ps HTOF 170 ps JLab Hall C 3.3.4 Aerogel Cherenkov AC HKS background π + reject Cherenkov c/n 1.2 GeV/c π + K + n = 1.05 Silica Aerogel π + 10 4 99 π + rejection 3.3.5 Water Cherenkov WC AC proton refection 1.2 GeV/c proton K + 1.08 n 1.28 n = 1.33 E01-011 K + 5 10 4 1 97.5 proton rejection 4 3.3.6 Lucite Cherenkov LC WC proton rejection TOF Hampton Univ. WC TOF TOF path length WC on line off line Particle ID

23 4 K + K + Particle ID Water Cherenkov WC E05-115 4.1: WC AC π + K + proton Cherenkov number of photoelectron HKS 1.05 1.35 GeV/c PMT 20 30 4.1 Water n = 1.33 Aerogel n = 1.05 π + K + proton Cherenkov number of photoelectron PMT 20 30 π + /K + AC HKS momentum acceptance 1.2 ± 0.15 GeV/c π + K + Cherenkov Particle ID K + /p WC HKS momentum acceptance K + proton Cherenkov 6 Particle ID Particle ID 1

24 4 K + index π + K + p AC Aerogel n = 1.05 WC Water n = 1.33 4.1: Cherenkov Particle ID 4.1 grouping grouping segment group group groupe K + [12] Cherenkov D dispersion group threshold n group e K + coincidence HKS K + HES coincidence e, e K + ( 6 HTOF1X n HTOF2X n AC n WC n ) (EHOD1 EHOD2) (4.1) n K + HKS single arm trig. HKS K + e, K + 6 HTOF1X n HTOF2X n AC n WC n (4.2) n p/π + /K + HKS Unbiased trig. HKS TOF proton K + π + proton π + singles rate HT OF1X HT OF2X (4.3) NIM Tohoku Universal Logic Module TUL TUL E01-011 [12] 4.2 background singles rate E05-115 singles rate background proton π + cut K + Particle ID

4.3. 25 4.2.1 singles rate E05-115 HKS singles rate 4.2 target π + K + proton single rate [8] 10 khz K + π + proton rate 1 2 Cherenkov on line Particle ID π + proton cut target Beam Intensity π + [khz] K + [khz] proton [khz] 7 Li 15 µa 5.4 0.068 7.6 10 B 30 µa 44 0.164 33 12 C 50 µa 13 0.161 21 40 Ca 30 µa 3.2 0.027 4.9 52 Cr 30 µa 9.7 0.079 13 4.2: E05-115 sigles rate target 100 mg/cm 2 [8] 4.2.2 Kaon Particle ID K + Particle ID WC proton rejection WC proton AC π + on line cut K + off line WC AC TOF K + WC AC K + 1.2 ± 0.15 GeV/c Cherenkov 4.2 Cherenkov Aerogel n = 1.05 1.2 0.15 GeV/c π + K + π + /K + K + /p n = 1.15 n = 1.33 Water proton K + Cherenkov β 5.3 proton K + 4.3 K + /p WC PMT number of photoelectron : NPE on line Particle ID WC K + /p K + /p 4.3 4.4 WC K + NPE run number 1 40 KEK

26 4 K + 4.2: Cherenkov Aerogel n = 1.05 1.2 0.15 GeV/c K + π + /K + K + /p n = 1.15 n = 1.33 Water proton K + 4.3: WC ϵ col = 10 PMT ϵ det = 25 PMT : 300 650 nm 1.2 0.15 GeV/c proton K + /p

4.3. 27 proton 99 K + over kill ratio 5 K + over kill ratio proton reject proton rejection 2 layer 95 4.2 proton K + 2 proton 5 K + S/N WC 4.4: WC1 WC2 run number 56000 61000 1 [11] 4.3.1 Amino-G salt 50 mg/l Amino-G salt Amino-G salt : 7-Amino-1. 3 naphthalenedisulfonic - acid. monopotassium salt hydrate : C 10 H 9 NO 6 S 2 248.0 308.0 355.0 nm 455.0 nm [10] Cherenkov PMT 300 650 nm Amino-G salt wavelength shifter PMT Cherenkov 4.5 Amino-G salt

28 4 K + 4.5: Amino-G salt 4.6 1 2 4.4 JLab Hall C Amino-G salt radiation damage [16] 4.6: E01-011 WC [13] 1 2 4.3.2 60 Co γ Amino-G salt radiation 4.7 wavelength shifter Amino-G salt radiation damage JLab Hall C WC 1 MHz 1 mgy/h 3 2 Gy beam dump radiation Gy

4.4. E05-115 Water Cherenkov 29 10 Gy 40 radiation damage 4.7: NPE 0 Gy NPE NPE [16] radiation damage Water Cherenkov 4.4 E05-115 Water Cherenkov 4.2 E05-115 singles rate Cherenkov CEBAF beam current 100 µa proton 250 khz 100 Hz proton rejection WC proton survival rato 4 10 4 1 rayer 98 proton rejection 6 HKS central momentum 1.2 GeV/c K + 50 NPE

31 5 K + /p Water Cherenkov Water Cherenkov WC proton rejection WC wavelength shifter Amino-G salt JLab Hall C radiation damage wavelength shifter radiation damage Water Cerenkov 5.1 Cherenkov Cherenkov Cherenkov WC Cherenkov Cherenkov c/n n : β 1/n Cherenkov 5.1 Cherenkov Cherenkov θ c cos θ c = ct/n βct = 1 nβ Cherenkov λ 1 λ 2 Cherenkov dn/dl dn dl = 2πα sin 2 θ c λ2 λ 1 dλ dn λ 2 dl (5.1) = 2πα(1 1 λ2 n 2 β 2 ) dλ λ 1 λ 2 (5.2) PMT ϵ col ϵ det dn dl = 2πα(1 1 λ2 n 2 β 2 ) dλ λ 1 λ 2 ϵ det(λ)ϵ col (λ) (5.3) number of photoelectron : NPE [9]

32 5 K + /p Water Cherenkov 5.1: Cherenkov 5.2 Cherenkov WC wavelength shifter 4.7 0 Gy radiation damage wavelength shifter 4 5.2.1 5.5 electron beam 5.1 NPE electron beam 1.0 GeV/c electron beam 1.2 GeV/c K + NPE 50 6 Water Cherenkov Cherenkov 5.3 2 1/λ 2 wavelength shifter wavelength shifter PMT

5.2. Cherenkov 33 5.2: 5.3:

34 5 K + /p Water Cherenkov particle β cosmic ray 0.97 31 25 electron beam 1.00 41 35 5.1: NPE β cosmic ray 0.6 GeV/c electron beam 1.0 GeV/c 5.2.2 SHIMAZU UV-2500PC 400 nm 5.5 5.4 5.5 5.2.3 PMT 5.6 UV-2500 PC 3 mm UVT UVT 300 nm WC 5.2.4 PMT PMT UV-PMT HAMAMATSU H7195 2 inch H7195UV 5.7 UV-PMT UV [17] UV-PMT PMT PMT PMT PMT

5.2. Cherenkov 35 5.4: 0.1 mm 150 mm 100 m 35 H 15.6 W 8 T cm PMT UVT UVT PMT HAMAMASTU : H7195 H7195 H7195 UV Amino-G salt 5.2: K + /p Water Cherenkov

36 5 K + /p Water Cherenkov 5.5: seal tape 1 2 3 100 5.6: UVT UVT 280 nm

5.2. Cherenkov 37 5.7: PMT [17] PMT UV-PMT 300 nm

38 5 K + /p Water Cherenkov 5.3 Water Cherenkov Cherenkov 5.8 5.3 5.8: Water Cherenkov A 5.3.1 PMT PMT UVT O - PMT O - 5.10 35 cm 60 cm A

5.3. Water Cherenkov 39 PMT PMT Cherenkov 37.6 H 15.2 W 8.1 T cm 34.6 H 15.6 W 8.7 T cm 3 mm HAMAMASTU : H7195 UV pure water n = 1.33 ; 18.2 MΩcm 5.3: Water Cherenkov 5.9:

40 5 K + /p Water Cherenkov 5.10: O - 60 cm 5.4 WC NPE simulation 5.11 µ electron 10 25 100 NPE 5.4.1 Hyper Cherenkov Simulator HYCS Hyper Cherenkov Simulator HYCS simulation HYCS Cherenkov simulation Cherenkov NPE PMT 5.5 PMT 5.7 5.6 90 /3 mm 5.4 [20] 96 /m 5.5 wavelength nm tranceparency m transmission rate /m 337 67.1 98.5 400 103.1 99.03 500 34.25 97.12 580 10.32 90.76 5.4: [20]

5.4. WC 41 5.11: µ electron Pure Water n = 1.33 NPE 10 PMT 300nm 650nm 25 particle cosmic ray electron β = 0.97 β = 1.0 PMT Normal UV-PMT Normal UV-PMT 17 17 18 18 134 143 142 152 5.5: HYCS simulation NPE

42 5 K + /p Water Cherenkov 6 5.5 1.2 GeV/c K + NPE 50 K + /p 5.5 Water Cherenkov WC 18.2 MΩcm 5.5.1 5.12 Water Cherenkov coinsidense UVT PMT Normal PMT UV-PMT 5.12: 5.5.2 NPE 5.14 5.15 PMT ADC Analog to Dedital Converter : LECROY RESARCH SYSTEMS 2249W

5.5. 43 12ch ADC one photoelectron peak gaussian NPE 5.14 5.15 peak gaussian 5.6 5.13 NPE NPE 2 5.16 + + UV-PMT NPE 5.15 2 Cherenkov 5.17 NPE 1.7 NPE 3 4.7 NPE 5 2.3 PMT Normal Normal UV-PMT UV-PMT Window UVT Acryl Quatz Glass UVT Acryl Quatz Glass 17 18 19 18 99 108 100 114 5.6: NPE NPE 2 wavelength shifter 140 150 NPE [13] 5.13: NPE wavelength shifter 140 150 NPE [13]

44 5 K + /p Water Cherenkov 5.14: NPE UVT + Normal PMT UVT + UV-PMT + Normal PMT + UV-PMT PMT 1 NPE 2 NPE

5.5. 45 5.15: NPE UVT + Normal PMT UVT + UV-PMT + Normal PMT + UV-PMT PMT 1 NPE 2 NPE

46 5 K + /p Water Cherenkov 5.16: NPE + + UV-PMT 5.16 2 5.17: + + UV-PMT 5.15

5.6. electron beam 47 5.6 electron beam 2008 3 12 STB electron beam 1.0 GeV/c WC B 5.7 5.18 beam NPE 5.18 NPE = 0.7 NPE 41 35 97 5.7: NPE 5.6.1 5.6 NPE 114 electron beam 97 0.6 GeV/c β 0.97 electron beam 1 GeV/c β 1.0 5.1 electron beam Cherenkov NPE 1 electron beam 1/cosθ Cherenkov HYCS simulation 130 140 200 nm HYCS PMT UVT 1 NPE PMT Normal PMT UV-PMT

48 5 K + /p Water Cherenkov 5.18: electron beam NPE NPE 97 NPE NPE = 0.7

5.7. 49 5.7 UV-PMT HYCS simulation 1 NPE UV-PMT HYCS 5.7 wavelength shifter Amino-G salt radiation damage K + /p Water Cherenkov Cherenkov UV-PMT PMT 2 5 NPE UVT UVT 1 2 HAMAMATSU H7195 H7195 UV 5 NPE 5.6 simulation

51 6 E05-115 WC Geant 4 [18] Geant 4 CERN HKS TOSCA [19] target proton K + HKS momentam acceptance 1.05 1.35 GeV/c 6.1: Geant 4 Splitter HKS Q-Q-D D Vaccum Extention HDC 1 HDC 2 TOF AC WC LC EDC 1 EDC 2 HKS 1.2 GeV/c Focal plane ) 6.1 Water Cherenkov electron beam 100 NPE E05-115 WC NPE 5.3 Cherenkov N NPE = N(λ)ϵ col ϵ det (λ) (6.1) ϵ col ϵ det (λ) PMT 5.1 N(λ) 5.7 ϵ det (λ) NPE ϵ col 6.1

52 6 E05-115 1.0 GeV/c electron beam simulation electron beam 5.11 10 MeV/c β 1.0 β N(λ)ϵ det (λ) NPE ϵ col cosmic ray β 0.95 533 31 ± 1 5.8 electron beam β 1.0 565 41 ± 1 7.3 N(λ)ϵ det (λ) NPE ϵ col cosmic ray 07/03 533 25 ± 1 4.7 cosmic ray 07/12 533 17 ± 1 3.4 electron beam 565 35 ± 2 6.2 N(λ)ϵ det (λ) NPE ϵ col cosmic ray Normal PMT 533 108 ± 3 20 comic ray UV PMT 884 114 ± 3 *13 electron beam UV PMT 938 97 ± 2 10.3 6.1: ϵ det * PMT ϵ col Normal PMT : 300 650 nm UV-PMT : 185 650 nm [17] 6.2 WC 6.2.1 E05-115 HKS momentum acceptance 1.2 ± 0.15 GeV/c K + proton NPE 6.2 NPE K + proton β momentum : 1.15 1.35 GeV/c 0.84 0.88 0.60 0.67 ϵ col = 7.3 31 34 5.5 15 ϵ col = 6.2 27 29 4.7 13 ϵ col = 10.3 74 80 13 36 6.2: K + proton NPE 6.2.2 simulation WC K + /p WC K + /p simulation 6.2 simulation NPE layer 1 segment

6.2. WC 53 Geant4 Cherenkov ϵ col = 10.3 ϵ det = 0.25 NPE K + peak 70 80 HKS centeral momentum 1.2 GeV/c K + NPE 75 6.2: simulation WC K + proton layer 1 segment NPE threshold cut K + proton survival ratio 6.3 K + /p layer 98 proton rejection K + kill ratio 1 layer 2.8 K + NPE peak K + kill ratio 6.3 K + NPE peak 50 K + kill ratio 2.8 segment K + survival ratio 6.4 segment 2 K + proton NPE K + NPE segment proton NPE high momentum high momentum K + /p 6.5 12 segment high momentum 7 segment proton 98 cut 1 layer K + survival ratio NPE segment HKS high momentum K + over kill ratio momentum segment No. 01 K+ over kill ratio 1 layer 15 8.6 segment No. 06 NPE 30 K + over kill ratio 2.2 NPE 32 No.06 low momentum proton rejection

54 6 E05-115 6.3: NPE cut WC K + proton survival ratio layer segment proton 98 cut K + over kill ratio 2.8 K + NPE peak K + kill ratio 90 2.8 75 2.8 60 2.8 54 2.8 36 3.8 30 5.1 24 6.0 15 13 6.3: Geant4 simulation K + NPE peak 1 layer K + kill ratio NPE 50 K + kill ratio

6.2. WC 55 6.4: simulation WC count 2 segment segment 01 + 02 03 + 04 05 + 06 07 + 08 09 + 10 11 + 12 segment high momentum K + segment high momentum segment proton high momentum K + /p

56 6 E05-115 6.3 Water Cherenkov 1 layer 98 proton rejection segment high momentum 5 NPE K + /p low momentum NPE 30 K + /p WC high momentum 5 segment 2 Layer 10 low momentum 98 proton rejection K + kill ratio high momentum 8.6 2.2 low momentum 2.2 1.0 segment K + 1 layer 2.9 K + over kill ratio 2 layer 5.6 4 10 4 proton rejection 6.5: segment proton 98 cut K + survival rario segment HKS high momentum high momentum K + /p HKS momentum acceptance 1.05 1.35 GeV/c K +

57 7 2 e,e K + Λ 89-009 E01-011 HKS tilt 12 Al Λ B 28 Λ E05-115 Ca Cr - background HES E01-011 HKS proton rejection WC 60 Co γ wavelength shifter Amino-G salt radiation damage 7.1 Water Cherenkov Amino-G salt WC Cherenkov PMT UVT PMT UV-PMT NPE 114 electron beam NPE 98 PMT UVT 1 UV-PMT PMT 5 7.1 PMT Cherenkov Cherenkov 1/λ 2 7.1 280 400 nm 400 nm 280 nm UVT Normal PMT NPE electron beam 41 97 Cherenkov

58 7 7.1: PMT Cherenkov

7.2. 59 1/λ 2 280 400 nm 400 650 nm Cherenkov 1300 2 7.1 200 280 nm 200 nm UV-PMT UV-PMT 1 UV-PMT 5 Cherenkov 200 280 nm 1800 UV-PMT Nϵ det (λ = 200 280) 400 10 40 NPE 10 1/4 5.5 99 200 nm 200 nm 5.4 400 nm 100 m [20] 99 /m 200 nm Cherenkov 280 nm 650nm 400 nm 280 nm NPE 2 UVT 5 UV-PMT 5 7.2 E05-115 HKS central momentum 1.2 GeV/c K + NPE 76 K + /p 1 layer 98 proton rejection K + kill rario 2.8 segment K + /p high momentum 5 K + /p low momentum NPE 30 K + /p WC high momentum 5 segment 2 Layer 10 low momentum layer segment 98 proton rejection K + over kill ratio low momentum 2.2 1.0 high momentum 8.6 2.2 K + 1 layer 2.9

60 7 K + over kill ratio 2 layer 5.6 proton 4 10 4 proton rejection 7.3 PMT wavelength shifter Amino-G salt 2008 12 18 60 Co 60 Co 320 MBq 2005 6 : 500 MBq 1 10 mgy Amono-G salt JLab Hall C Amino-G salt

61 TA Water Cherenkov 1

62 7 2009 2

63 A 5 PMT A.1 A.1 A.1: A.2 PMT PMT UVT PMT O - A.2 O - 1 mm

64 A A.2: PMT mm O - 1 mm A.3 A.4 A.3 A.5 A.6 A.7

A.3. 65 A.3: PMT A.4: PMT A.5:

66 A A.6: A.7:

67 B WC (Water Cherenkov counter) B.1 Number of Photoelectron B.1: Water Cherenkov Counter B.1.1 2008 3 Water Cherenkov counter WC Amino-G salt 200 mg/l 100 mg/l 50 mg/l 10 mg/l Pure Water Pure Water Number of Photoelectron NPE B.1 - PMT Photon 8.1 cm 15.6 cm Photon

68 B WC (Water Cherenkov counter) NPE Old Pure Pure 10mg 50mg 100mg 200mg 8.1 cm 41 35 118 116 87 89 15.6 cm 83 75-226 167 176 B.1: Number of Photoelectron B.1.2 2008 12 3 B.2 box NPE 41 35 98 B.2: NPE 3 12

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70 B WC (Water Cherenkov counter) [16] e,e K + K 2007 [17], http://jp.hamamatsu.com/ [18] http://geant4.web.cern.ch/geant4/ [19] http://www.vectorfields.co.uk/ [20], http://www-sk.icrr.u-tokyo.ac.jp/sk/index.html [21] 3 2002