1219

˙ ‫঺ڀݚ‬հ

ILC-TPC ͷͨΊͷߴ։‫ ཰ޱ‬GEM ‫ܕ‬ήʔτ૷ஔͷ։ൃ૯߹‫ڀݚ‬େֶӃେֶ

The Graduate University for Advanced Studies (SOKENDAI)খ ઒ ஐ ‫ٱ‬0
ogawat@post.kek.jp
2017 ೥ (ฏ੒ 29 ೥) 2 ݄ 6 ೔

͸͡Ίʹ

1

࣮‫Ͱݧ‬΋ར༻͞Ε͍ͯΔɻTPC ͸෺ཧ͔Βͷཁ‫ʹٻ‬ରͯ͠े෼ͳӡಈྔ෼ղೳΛ࣋ͭɻ·ͨ࿈ଓτϥοΩϯά

ࠃࡍϦχΞίϥΠμʔʢInternational Linear Collider:Λߦͳ͏ͷͰଟ਺ͷϋυϩϯδΣοτͷࣄ৅ʹ͓͍ͯ΋

ILCʣ‫ܭ‬ը͸ɼશ௕໿ 30 km ͷ௚ઢ‫ܕ‬Ճ଎‫ʹث‬ΑΓిߴ͍ඈ੻ೝࣝೳྗΛ࣋ͭɻ·่ͨյ఺‫ݕ‬ग़‫ث‬Λӽ͑ͯඈࢠɼཅిࢠʢૉཻࢠʣΛՃ଎িಥͤ͞ɼ‫ࡏݱ‬ୡ੒Մೳͳ

Ϳ௕ण໋தੑཻࢠɼ‫ݕ‬ग़‫಺ث‬૚ͰΧʔϧ͢Δ௿ӡಈྔཻ࠷ߴΤωϧΪʔͰӉ஦૑੒ 1 ஹ෼ͷ 1 ඵ‫ޙ‬Λ࡞Γग़࣮͢ࢠͷࣝผͳͲɼ༷ʑͳࣄ৅ʹରͯ͠ରԠՄೳͰ͋Δɻ༰‫ܭݧ‬ըͰ͋Δɻ࣌ؒͱۭؒɼ෺࣭ͱྗͷ౷Ұతཧղͷͨ‫಺ث‬͸ΨεͰຬͨ͞Ε͍ͯΔͷͰ௿෺࣭ྔͰ͋ΔҰํɼΊɼඪ४ཧ࿦Λ௒͑Δ৽෺ཧΛ໌Β͔ʹ͠ɼͲͷΑ͏ʹΘ͔ͣͳΤωϧΪʔଛࣦ͔Βཻࢠࣝผ΋Մೳͱ͢Δɻ͜Ӊ஦͕ੜ·Εɼ෺࣭͕ੜ·Εͨͷ͔ͱ͍͏Ӊ஦૑ੜͷಾΕΒͷಛ௃ʹΑΓɼILC ࣮‫༻ݧ‬ͷఏҊ‫ݕ‬ग़‫ث‬ͷ 1 ͭͰ͋ʹഭΔ΋ͷͰ͋ΔɻILC ͷՃ଎‫ؔ͢ʹث‬Δٕज़ઃ‫ܭ‬ใࠂ
ॻʢTechnical Design Report: TDR [1] ʣ͓Αͼଌఆ‫ؔ͢ʹث‬Δৄࡉ‫ج‬ຊઃ‫ॻܭ‬ʢDetailed Baseline Design:

Δ ILD ( ΞδΞɾϤʔϩούؒͰ‫ڞ‬ಉઃ‫ܭ‬தͷଌఆ‫໊ث‬শ International Large Detector ) ʹ͓͍ͯ΋தԝඈ੻‫ݕ‬ग़‫͞༻࠾ͯ͠ͱث‬Ε͍ͯΔɻ

DBD [2]ʣ͕͢Ͱʹ 2012 ೥ʹൃද͞Ε͓ͯΓɼ2016 ೥‫ࡏݱ‬ɼߋʹৄࡉͳ‫ݕ‬౼͕จ෦Պֶলʹ͓͍ͯ༗ࣝऀձٞ
ʹΑΓਐΜͰ͍Δɻ֤ࠃͷ‫ʹऀڀݚ‬ΑͬͯՃ଎‫͓ث‬Αͼ‫ݕ‬ग़‫ث‬ͷ࠷ऴઃ‫ܭ‬΋ߦͳΘΕ͓ͯΓɼILC ࣮‫͚ͨ޲΁ݱ‬ٕज़‫ݕ‬౼͸࠷ऴஈ֊ʹདྷ͍ͯΔɻࠓճɼࢲࣗ਎͕ؔΘͬ
͍ͯΔ ILC-TPC ͷ‫ڀݚ‬։ൃʹ͍ͭͯ‫঺ڀݚ‬հͷ‫ػ‬ձΛ͍͚ͨͩͨͷͰɼILC-TPC ͷ࠷ॏཁ՝୊ͷ 1 ͭͰ͋Δ

GEM ‫ܕ‬ήʔτ૷ஔͷ։ൃʹؔ͢Δ‫ʹڀݚ‬য఺Λ౰ͯͯ঺հΛߦ͍͍ͨͱࢥ͏ɻʢILC ͷ෺ཧ [3]ɼଞ‫ݕ‬ग़‫[ ث‬4]ʹؔͯ͠͸ա‫ߴʹڈ‬ΤωϧΪʔχϡʔεʹ‫͞ࡌܝ‬Εͨ‫ݚ‬‫঺ڀ‬հΛ‫͍ͩͯ͘͞ݟ‬ɻ·ͨ ILC ͷͨΊͷ TPC ͱͯ͠ॻ͔Εͨ‫঺ڀݚ‬հʹ [5] ͕͋Γ·͢ɻʣਤ 1: TPC ͷ໛ࣜਤɻίϥΠμʔ࣮‫Ͱݧ‬͸িಥ఺Λऔ

1.1Time Projection Chamber: TPC

TPC ͸ີด༰‫ʹ಺ث‬ΞϧΰϯɼωΦϯͳͲͷ୯‫ࢠݪ‬෼ࢠΨεΛओ੒෼ͱͨࠞ͠߹Ψε෧ೖ͠ɼՙిཻࢠͷ௨ΓғΉΑ͏ʹઃஔ͞ΕΔɻฏߦʹ഑ͨ͠ి৔ɼ࣓৔ʹΑΓి཭ిࢠͷԣ֦ࢄΛ཈͑ͳ͕Β୺෦΁υϦϑτͤ͞૿෯͓ΑͼಡΈग़͠Λߦ͏ɻաʹΑΔి཭աఔΛར༻͠ 2 ࣍‫ݩ‬ͷฏ໘৘ใͱ 1 ࣍‫ݩ‬ͷ࣌ؒ৘ใʹΑΓ 3 ࣍‫ݩ‬ͷඈ੻Λ࠶ߏ੒Մೳͱ͢Δଌఆ
‫͋Ͱث‬Δʢਤ 1ʣɻ1985 ೥ʹ David R. Nygren ͕ͦͷ‫ݪ‬ཧ [6] ΛఏҊ͔ͯ͠Βɼಛʹ TPC ͕࣋ͭಛ௃ͷͨΊʹɼίϥΠμʔ࣮‫͍༻ʹݧ‬ΒΕ͖͍ͯͯΔɻٕज़ͷൃలͱͱ΋ʹ TPC ࣗମͷվྑ΋ਐΈɼ‫ݱ‬୅ͷଟ͘ͷૉཻࢠ
0 LC-TPC ೔ຊάϧʔϓΛ୅දͯ͠

1.2

ILC ͷͨΊͷ TPC ͱͦͷ໨ඪੑೳ

ILC ࣮‫Ͱݧ‬͸‫ج‬ຊཻࢠϨϕϧͰੜ੒ࣄ৅ͷ࠶ߏ੒Λߦ
͏ɻILC ͷ໨తͷ 1 ͭͰ͋ΔώοάεηΫλʔΛ‫ؚ‬Ήిऑ૬‫༻࡞ޓ‬աఔͷਫ਼ີଌఆʹ͸ɼW ͓Αͼ Z ཻࢠͷෆม࣭ྔ͕෼཭Մೳͳ΄ͲͷδΣοτΤωϧΪʔ෼ղೳ͕

2
220

ඞཁͱͳΔɻ͜ΕΛ࣮‫͢ݱ‬ΔͨΊʹ͸δΣοτதͷཻࢠిࢠͷυϦϑτ଎౓, ి৔ʣΛද͢ɻి৔ͱ࣓৔͕ฏߦ

Λ෼཭͠ɼ֤ʑʹରͯ͠ΤωϧΪʔ෼ղೳͷྑ͍‫ݕ‬ग़‫ث‬ʹ͔͚ΒΕΔ TPC Ͱ͸ɼ࣓৔ʹΑΔϩʔϨϯπྗ͕৴ͷ৘ใΛ༻͍Δඞཁ͕͋Δ ( Particle Flow Analysis [3]߸ిࢠʹಇ͖ɼਐߦํ޲ʹର࣓ͯ͠৔ʹ‫Ͱܗ͖ͭ͘ר‬ԣ)ɻΑͬͯ ILC ͷதԝඈ੻‫ݕ‬ग़‫ʹث‬͸ɼଟ਺ͷδΣοτ

֦ࢄ͕཈͑ΒΕͳ͕ΒҠಈ͢Δɻߴ͍Ґஔ෼ղೳ͕‫ٻ‬ΊΛ‫ؚ‬Ήࣄ৅ʹ͓͍ͯ΋ՙిཻࢠΛඈ੻‫ݕ‬ग़‫ޙث‬ஈʹઃΒΕΔ ILC-TPC Ͱ͸ߴ࣓৔Ͱԣ֦ࢄ͕খ͘͞ͳΔΨεஔ͞ΕΔΧϩϦϝʔλ಺ͷཻࢠΫϥελͱɼॏෳͳ͠Ͱ

͕ඞཁͱ͞Εɼ࣓৔தͰԣ֦ࢄ͕খ͍͜͞ͱ͕஌ΒΕΔ

ҰରҰରԠΛ࣮‫ͤ͞ݱ‬ΔͨΊͷߴ͍ඈ੻෼཭ೳྗɼ൓௓

CF4 ɼϖχϯάޮՌ1 ʹΑΓΨε૿෯཰Λ૿΍ͤΔͱ‫ظ‬࣭ྔ๏ʹΑΔώοάεཻࢠͷ࣭ྔͷߴਫ਼౓ଌఆͷͨΊͷ଴Ͱ͖Δ iC4 H10 ͕ࠞ߹͞Εͨ Ar ϕʔεΨεʢT2K Ψߴ͍ӡಈྔ෼ղೳ͕ཁ‫͞ٻ‬ΕΔɻͱΓΘ͚ӡಈྔ෼ղೳ

ε2 ɼωτ ∼10(3.5 T)ʣ͕‫ࡏݱ‬ͷͱ͜Ζީิͱͳ͍ͬͯ

ʹؔͯ͠‫͑ݴ‬͹ɼILC ͕໨ࢦ͢෺ཧ͔Βͷཁ‫ͯ͠ͱٻ‬

[GeV

−1

] ͕۩ମతʹࣔ͞Ε͓ͯΓʢ͜Ε͸಺֎૚ͷγϦίϯτϥοΧʔͷ৘ใ΋༻͍ͨ৔
߹Ͱ͋ΔɻTPC ୯ಠͰ͸ 1 × 10

−4

[GeV

−1

Δɻ T2K Ψεͷಛ௃Λਤ 2 ʹࣔ͢ɻ3.5 T ͷ࣓৔Լʹ͓√͍ͯɼυϦϑτ଎౓͕࠷େ෇ۙͰԣ֦ࢄ͸ 30 µm/ cm
ఔ౓ͱͳΔɻ

]ʣɼ͜Ε͸

ա‫ڈ‬ͷిࢠཅిࢠিಥ࣮‫ݧ‬ʢLEPʣɼ·ͨ‫ߦࡏݱ‬ΘΕ͍ͯΔେ‫ܕ‬ϋυϩϯিಥ࣮‫ݧ‬ʢLHCʣͷӡಈྔ෼ղೳΑΓ΋͓Αͦ 1 ܻྑ͍ਫ਼౓ͱͳΔɻ࣍ࣜ [8] ͷΑ͏ʹӡಈྔ෼ղೳ͸ՙిཻࢠ͕௨ͬͨҐஔͷଌఆਫ਼౓ʹґଘ͢ΔͷͰɼਫ਼౓ྑ͍ӡಈྔ෼ղೳΛಘΔͨΊʹ͸ՙిཻࢠʹΑ
Δి཭͕ൃੜͨ͠ҐஔΛਫ਼౓Α͘ଌఆ͢Δඞཁ͕͋Δɻ
!
720
σrφ
2
(1)
σpt /pt =
2
0.3BL
N +4

µm/ cm (µm/ns)

σ(1/pt ) = 2 × 10

−5

Ar:CF4:isoC4H10=95:3:2

3

10

Longi Diffusion
Trans Diffusion @ 0.0T

Trans Diffusion @ 1.0T

102
Trans Diffusion @ 3.5T্ࣜʹ͓͍ͯ pt , σpt , σrφ ͸ͦΕͧΕՙిཻࢠԣํ޲ӡ

Drift Velocityಈྔɼଌఆ‫ث‬ͷԣํ޲ӡಈྔ෼ղೳͱҐஔ෼ղೳΛࣔ

10

͢ɼN ͸ଌఆ఺ͷ਺ɼB[T] ͓Αͼ L[m] ͸࣓৔ͷ‫͞ڧ‬10ͱଌఆ‫ث‬ͷඈ੻‫ݕ‬ग़௕Ͱ͋Δʢ͜͜Ͱ͸ଟॏࢄཚͷ‫د‬༩࣓৔ͳͲΛߟ͑ͨ৔߹ɼILC-TPC ʹཁ‫͞ٻ‬ΕΔҐஔ෼ղೳ σrφ ͸ 2.2 m ͷ࠷େυϦϑτ‫ ͯͬ౉ʹ཭ڑ‬100 µm

102

103

E [V/cm]͸ແࢹ͍ͯ͠ΔʣɻILC-TPC ʹཁ‫͞ٻ‬ΕΔӡಈྔ෼ղೳɼ·ͨ‫͑ߟࡏݱ‬ΒΕ͍ͯΔ‫ݕ‬ग़‫ث‬αΠζɼՃ͑ΒΕΔ(20°C, 1atm)

ਤ 2: Magbolts [7] Ͱ‫͞ࢉܭ‬Εͨ T2K ΨεதͰͷిࢠͷυϦϑτ଎౓ͱ֦ࢄఆ਺ͷి৔ґଘʹ͍ͭͯɻҎԼʹ͢Δඞཁ͕͋Δɻ

1.3

1.4

T2K ΨεཅΠΦϯͷӨ‫ͱڹ‬ήʔτ૷ஔͷඞཁੑ

TPC ʹ͸ͦͷ։ൃ౰ॳ͔ΒɼՙిཻࢠʹΑΔి཭͓

TPC ͷҐஔ෼ղೳ͸ॆర͢ΔΨεʹΑͬͯେ͖͘ࠨ

Αͼిࢠ૿෯Ͱੜ͡ΔཅΠΦϯ‫͕܈‬υϦϑτྖҬͷిӈ͞ΕΔɻυϦϑτ‫཭ڑ‬ͷ௕͍େ‫ ܕ‬TPC Ͱ͸ɼՙిཻ৔Λཚ͠ɼଌఆ͞ΕΔ 3 ࣍‫ݩ‬ඈ੻Λ࿪·ͤΔ‫ݹ‬యతͳࢠͷ௨աʹΑΔిࢠͷి཭͔ΒΞϊʔυ໘ͰͷಡΈग़͠
·Ͱɼ৴߸ిࢠ͕υϦϑτ͍ͯ͠Δؒ͸Ψεதͷ෼ࢠͱিಥΛ‫܁‬Γฦ͢ͷͰɼॎ͓Αͼԣํ޲ʹ֦ࢄͷӨ‫ڹ‬Λड໰୊͕͋ΔɻΑͬͯ TPC Λ࣮‫͏࢖ʹݧ‬৔߹͸ͦͷ࣮‫ݧ‬‫ͯؔ͠ʹڥ؀‬΋ߟྀ͢Δඞཁ͕͋ΔɻILC ࣮‫ݧ‬ͷ৔߹ʹ͸ిࢠɼཅిࢠϏʔϜͷ࣌ؒߏ଄ʹ஫ҙ͠ͳ͚Ε͹

͚Δɻಛʹԣํ޲ͷ֦ࢄ͸݁Ռͱͯ͠ॳ‫཭ిظ‬ͷൃੜҐͳΒͳ͍ɻྫ͑͹ϏʔϜͷ੍ಈ์ࣹʹΑΔେྔͷిࢠཅஔΛ΅΍͔͠ɼҐஔ෼ղೳΛѱԽͤͯ͞͠·͏ɻ͔͠͠

ిࢠରόοΫάϥ΢ϯυ͕ߟ͑ΒΕɼ͜ΕΒՙిཻࢠ͕

ͳ͕Βɼԣํ޲ͷ֦ࢄʹؔͯ͠͸࣍ࣜͷΑ͏ʹ࣓৔ͷޮΨεதΛ௨ա͢Δͱి཭ʹΑΓυϦϑτྖҬதʹిࢠՌ͕ೖΔ͜ͱ͕஌ΒΕ͓ͯΓɼ৴߸ిࢠͷԣ֦ࢄͷӨ‫ڹ‬Λ཈੍͢Δ͜ͱ͕Ͱ͖Δɻԣํ޲֦ࢄఆ਺ Cd ͸ɼ

Cd (B, E) = "1
1 + (ωτ )2

Cd (0, E)(2)ω ͸αΠΫϩτϩϯৼಈ਺ ( ω=eB/m, e, B, m ͸ૉిՙ, ࣓৔, ిࢠ࣭ྔ )ɼτ ͸ిࢠ͕‫ͱࢠݪ‬িಥͯ࣍͠ͷ෼ࢠͱিಥ͢Δ·Ͱͷฏ‫ࣗۉ‬༝࣌ؒ ( τ =mv̄/eE, v̄, E ͸

1 ࠞ߹ΨεதͰҰํͷ෼ࢠ A ͕ྭ‫ى‬ঢ়ଶͰ͋ΓɼA ͷ४҆ఆ४ҐΑΓ΋ి཭ϙςϯγϟϧͷ௿͍෼ࢠ B ʹিಥ͠ B ͕ి཭Λ͓͜͢ޮՌɻ
AX + B → A + B + + e− ɻAr ͷ४҆ఆྭ‫ى‬ঢ়ଶ͸͓Αͦ 11.6eVʹର͠ɼiC4 H10 ͷి཭ϙςϯγϟϧ͸ 10.8eV
2 T2K Ψεͷ੒෼ൺ͸ Ar : CF : iC H
44 10 = 95 : 3 : 2 Ͱ͋Δɻԣ֦ࢄΛ཈͑ΔͨΊʹ͸্‫ه‬ͷ ωτ ͕େ͖͍ΨεͰ͋Ε͹ྑ͍ɻω ͸ Bͷେ͖͞Ͱܾ·ΔͷͰɼτ ͕େ͖͍Ψε͕๬·ΕΔɻτ ∝ l(ฏ‫ࣗۉ‬༝ߦఔ) Ͱ͋Γɼ͜ͷ஋͸෼ࢠͱͷஅ໘ੵʹ൓ൺྫ͢Δɻిࢠͷ CF4 ෼ࢠͱͷ࠷େஅ໘ੵ͸ Ar ෼ࢠͱͷஅ໘ੵ͕େ͖͘ͳΔલʹ͋ΔͷͰɼిࢠΛ Ar ෼ࢠͱͷஅ໘ੵ࠷খ෇ۙʹཹ·ΒͤΔ͜ͱ͕Ͱ͖ΔɻΑͬͯ τ ΛҰൠతͳΨεΑΓ΋େ͖͘͢Δ͜ͱ͕Ͱ͖Δ [13]ɻ

3221

ཅΠΦϯର͕ੜ੒͞ΕΔʢ1 ࣍ཅΠΦϯʣɻ Ξϊʔυ໘Φϯःณޮ཰ͷྑ͍ήʔτ૷ஔΛ࢖༻͢Ε͹ɼे෼ʹ 2ʹ౸ୡͯ͘͠Δ৴߸ిࢠ͸୺෦‫ݕ‬ग़‫͍͓ͯʹث‬Ψε૿࣍ཅΠΦϯ‫܈‬ͷޮՌΛଧͪফ͢͜ͱ͕ՄೳͰ͋Δ͜ͱ΋෯͞Εɼ͜ͷաఔͰ΋େྔͷཅΠΦϯ͕ੜ੒͞Ε (2 ࣍ࣔ͞Ε͍ͯΔʢਤ 4ʣɻཅΠΦϯ)ɼి৔ʹԊͬͯυϦϑτྖҬʹ‫͍ͯ͘͠ྲྀٯ‬(Ion Back Flow: IBF)ɻཅΠΦϯͷυϦϑτ଎౓͸ిࢠͷ O(10−4 ) ∼ O(10−3 ) ఔ౓ͱඇৗʹ஗͘ɼAr ΠΦϯͷ৔߹ɼ300 K Ͱͦͷқಈ౓͸ 1.6 cm2 /(V · sec) ఔ౓Ͱ͋ΓɼυϦϑτి৔ 230 V/cm ͷઃఆͰ͸υϦϑτ଎౓ ∼ 370 cm/sec ఔ౓ͱͳΔʢT2K Ψεதʹ͸ ArΠΦϯͱ iC4 H10 ʹΑΔΠΦϯަ‫׵‬ͷͨΊ iC4 H10 ΠΦϯ͕ଘࡏ͍ͯ͠Δͱߟ͑ΒΔɻͦͷқಈ౓΋͓͓Αͦ

1.6 cm2 /(V · sec) ఔ౓Ͱ͋Δ [9] ʣɻઃ‫ ্ܭ‬ILC ͷϏʔϜ‫܁‬Γฦ͠प೾਺͸ 5 Hz ͱઃఆ͞Ε͓ͯΓɼ200 msec

ຖʹ 1 ࣍ཅΠΦϯ‫͕܈‬ੜ੒͞ΕΔͱ૝ఆͰ͖Δɻ͜ͷ 1࣍ཅΠΦϯ‫܈‬͸ɼTPC ͷυϦϑτྖҬதʹԁ౵ঢ়ʹॏͳΓ߹ͬͯɼ֓Ͷ 3 ‫ݸ‬ଘࡏ͢Δ͜ͱ͕༧૝͞ΕΔʢ4 ͭ໨͕ੜ੒͞ΕΔࠒʹ͸ 1 ͭ໨͸தԝΧιʔυʹ‫ٵ‬ऩ͞Ε
Δʣɻੜ੒͞ΕΔ 2 ࣍ཅΠΦϯ͸ 1 ‫ݸ‬ͷ৴߸ిࢠʹ૿෯෦ͰͷΨε૿෯཰Λֻ͚ͨ΋ͷʹͳΔɻઃ‫ ্ܭ‬ILC ͷ

1 όϯντϨΠϯʢ0.73 msecʣதʹ͸ 1312 όϯν͋Δ
ͷͰɼް͞ 0.5 cm ఔ౓ͷඇৗʹߴີ౓ͳԁ൘ঢ়ͷཅΠΦϯ‫͕܈‬ɼ1 ࣍ཅΠΦϯ‫܈‬ಉ༷ɼ‫ܧ‬ଓతʹ 3 ‫ݸ‬ଘࡏ͢Δ
ͱߟ͑ΒΕΔɻͦͷུ֓ਤΛਤ 3 Ͱද͢ɻ͜Ε·Ͱʹήʔτ૷ஔͳ͠

ήʔτ૷ஔ͋Γ̍࣍ཅΠΦϯ

8.5 µm

8.5 µm̎࣍ཅΠΦϯ

60.0 µm

0.01 µm

߹‫ܭ‬

70 µm

8.5 µmਤ 4: ԁ൘ঢ়ͷ 2 ࣍ཅΠΦϯ‫ʹ܈‬ΑΔඈ੻࿪ΈͷӨ‫ڹ‬༧૝ਤͱɼੜ੒ཅΠΦϯ‫ʹ܈‬ΑΔҐஔ෼ղೳ΁ͷӨ‫ڹ‬ɻIon

Back Flow=3 ͱԾఆͯ͠ͷධՁɻ

1.5

GEM ‫ܕ‬ήʔτ૷ஔ

LEP ͓Αͼ LHC ࣮‫Ͳͳݧ‬ͷ‫ݕ‬ग़‫͍͓ͯʹث‬ɼϫΠϠʔνΣϯόʢMulti Wire Proportional Chamber:

MWPCʣ͕༻͍ΒΕͨେ‫ܕ‬ͷ TPC Ͱ͸ɼυϦϑτి৔Λ‫ܗ‬੒͢ΔϑΟʔϧυϫΠϠʹɼ͋Δ͍͸ྡ઀͢ΔϫΠϠؒʹిҐࠩΛ༩͑ͯཅΠΦϯͷ‫ٵ‬ऩΛߦ͍ͬͯͨ (ҰछͷཅΠΦϯήʔτ)ɻILD-TPC Ͱ͸૿෯‫ʹߏػ‬ϚΠΫϩύλʔϯΨε‫ݕ‬ग़‫( ث‬Micro Pattern Gaseous Detec-

tor: MPGD) Λ༻͍Δઃ‫ܭ‬ͷͨΊɼଟ਺ͷϫΠϠΛ‫ݕ‬ग़‫୺ث‬෦ʹுΔߏ଄͸ɼϫΠϠΛுΔͨΊͷे෼ͳுྗ
͕ඞཁͱͳΓɼ‫ࡏݱ‬ͷ MPGD Λ༻͍ͨ‫ݕ‬ग़‫ث‬ͷߏ଄ʹਤ 3: TPC υϦϑτྖҬதʹ͓͚Δ 2 ࣍ཅΠΦϯ‫܈‬ͷ෼෍ͱ৴߸ిࢠͷυϦϑτʹ༩͑ΔӨ‫ڹ‬ɻ

LC-TPC ೔ຊάϧʔϓ͸ɼILC ‫ڥ؀‬ԼͰੜ੒͞ΕΔ͜ΕΒԁ౵ঢ় 1 ࣍ཅΠΦϯ‫܈‬ɼ͓Αͼԁ൘ঢ় 2 ࣍ཅΠΦϯ‫܈‬ͷҐஔ෼ղೳ΁ͷӨ‫͍ͯͭʹڹ‬γϛϡϨʔγϣϯ‫ࢉܭ‬߹Θͣɼͦͷ޻ֶతઃ‫ܭ‬Λ‫ݟ‬௚͢ඞཁ͕ग़ͯ͘Δɻ·ͨ

E × B ͷӨ‫ʹڹ‬ΑΔҐஔ෼ղೳѱԽ΋‫ݒ‬೦͞ΕΔɻͦ

Μͳதɼ2006 ೥ʹΨεిࢠ૿෯‫( ث‬Gas Electron Multi-

plier: GEM) ͷൃ໌ऀͰ΋͋Δ F. Sauli ʹΑͬͯ GEM
Λ༻͍ͨήʔτ‫͕ߏػ‬ఏҊ͞Εͨɻ GEM ͸͜Ε·ͰΨε૿෯૷ஔͱͯ͠ͷΈೝࣝ͞Ε͍͕ͯͨɼ਺ V ఔ౓Λߦ͖ͬͯͨɻͦͷ݁Ռ 1 ࣍ཅΠΦϯ‫܈‬͸Ґஔ෼ղೳͷͷ௿ిѹͰ࢖༻͢Δ͜ͱʹΑΓɼཅΠΦϯ્ࢭບͱͯ͠

ѱԽ͸ແࢹͰ͖Δ΄Ͳখ͍͕͞ɼ2 ࣍ཅΠΦϯ‫ʹ܈‬ΑΔ

࢖͑ΔՄೳੑΛࣔͨ͠ [10]ɻཅΠΦϯ͸ిࢠʹൺ΂ͯेҐஔ෼ղೳͷѱԽ͸ TPC ͷ࠷಺૚Ͱ͸͓͓Αͦ 60 µm

෼ʹॏ͍ͨΊ֦ࢄ͕গͳ͘ి‫ྗؾ‬ઢʹԊͬͯӡಈ͢Δɻ

ʹୡ͠ɼ‫ٻ‬ΊΒΕΔੑೳʹରͯ͠ແࢹͰ͖ͳ͍Ө‫ڹ‬Λ‫ٴ‬΅͢͜ͱ͕ࣔ͞Εͨ (IBF=3 ͱԾఆ3 )ɻͱಉ࣌ʹɼཅΠ
3 Ion Back Flow(IBF)=3 ͱ͸ిࢠ͕ 1 ‫ݸ‬ೖͬͨ৔߹ʹ 3 ‫ݸ‬ཅΠΦϯ͕໭ͬͯ͘Δͱ͍͏ఆٛɻ͜Ε͸ྫ͑͹ΨεήΠϯ 3000ɼཅΠΦϯ્ࢭ཰ 10−3 ͱ૝ఆ͢Δ͜ͱͱ౳͍͠ɻ͔͠͠ͳ͕Β 10−3 ͱ͍͏஋͸ 3 ஈ GEM ΍ Micromegas Λ༻͍ͯɼυϦϑτి৔Λे෼ʹऑͨ͘͠৔߹ʹୡ੒Մೳͳ஋Ͱ͋Γɼ2 ஈ GEM ͷ৔߹Ͱ͸਺%͔Β
10%ͷϨϕϧͰ͋Δɻ͜ͷ৔߹্‫ه‬ͷ࿪Έ͸ 100 ഒۙ͘ʹͳΔՄೳ
ੑ͕͋Δɻ͜ͷ఺΋ཅΠΦϯήʔτ͕ඞཁͱͳΔେ͖ͳཧ༝Ͱ͋Δɻ4
222

GEM ʹ਺ V ఔ౓ͷ‫ిٯ‬ѹΛҹՃ͢Δ͚ͩͰɼ΄΅ཅΠΦϯΛ GEM ද໘ʹ‫ٵ‬ऩ͢Δ͜ͱ͕Ͱ͖Δͱ͞ΕΔɻલड़ͷ௨Γ ILC-TPC ‫ڥ؀‬ԼͰ͸‫࣓ڧ‬৔͕ՃΘΓిࢠͷ֦ࢄΛ཈͑Δඞཁ͕͋ΔɻҰํͰ௨ৗͷ GEM ͷ։‫཰ޱ‬͸͍͍ͤͥ 30 %ఔ౓Ͱ͋Δɻ໰୊ͱͳΔͷ͸࣓৔ʹ‫͖ר‬ͭ͘‫Ͱܗ‬ԣ֦ࢄ͕཈͑ΒΕ͍ͯΔ৴߸ిࢠ͕ɼυϦϑτྖҬʹઃஔ͞ΕΔ GEM ‫ܕ‬ήʔτΛಁա͠ɼཁ‫͞ٻ‬ΕΔ
Ґஔ෼ղΛୡ੒͠ಘΔఔͷ৴߸Λ֬อͰ͖Δ͔Ͳ͏͔Ͱ
͋Δɻਤ 5: ॳ‫ظ‬ͷബ͍ GEM ‫ܕ‬ήʔταϯϓϧͷ֦େਤͱϚάωοτΛ༻͍ͨిࢠಁա཰ଌఆɻGEM ઈԑ෦ͷް͞͸΄΅੡଄‫ݶ‬քͷ 14 µm Ͱ͋Δɻ͜Ε·Ͱͷ‫ڀݚ‬։ൃ

2࣓৔தͰిࢠಁա཰ͷଌఆΛߦͬͨ (ਤ 5 ӈ)ɻ 1 T ͷϦχΞίϥΠμʔͷͨΊͷ TPC ͷ։ൃ‫ڀݚ‬͸ LC-࣓৔Լʹ͓͍ͯɼ5 V ΛҹՄ͠ήʔτΛ։͍ͨঢ়ଶͰͷ

TPC άϧʔϓͱ‫ݺ‬͹ΕΔࠃࡍίϥϘϨʔγϣϯͷԼͰిࢠಁա཰͸ 60 %ఔ౓ͱͳΓɼγϛϡϨʔγϣϯΛ࠶ਐΊΒΕ͍ͯΔɻLC-TPC άϧʔϓ಺Ͱɼ೔ຊάϧʔϓ‫͢ݱ‬Δ΋ͷͱͳͬͨɻଞͷαϯϓϧ΋ಉ༷ʹ͓͓Αͦγ͸ཅΠΦϯήʔτ૷ஔͷ։ൃΛ೚͞Ε͍ͯΔɻILC ࣮‫ݧ‬ϛϡϨʔγϣϯΛ࠶‫͢ݱ‬Δ΋ͷͱͳͬͨ (ਤ 6)ɻ͔͠͠

ʹ͓͍ͯɼIBF ͷ໰୊Λ๷͙ͨΊͷཅΠΦϯήʔτ૷ஔͳ͕Βɼిࢠಁա཰ 60 %ͱ͍͏஋͸ɼՙిཻࢠͷ௨ա͕ཁ‫͞ٻ‬ΕΔੑೳΛຬͨ͢͜ͱ͸ɼILC ࣮‫ݧ‬ͷओඈ੻‫ݕ‬ʹΑͬͯੜ੒͞Εͨి཭ిࢠ͕ 60 %ʹ‫ݮ‬গ͢Δ͜ͱͰग़‫ ͯ͠ͱث‬TPC ͕੒ཱ͢Δ͔Ͳ͏͔Λࠨӈ͢Δ࠷ॏཁ͋Γɼ‫ޙ‬ड़͢ΔҐஔ෼ղೳࣜΑΓ෼ղೳ͕໿ 30 %ྼԽ

՝୊ͷ 1 ͭͱͳ͍ͬͯΔɻ͜͜Ͱ͸೔ຊάϧʔϓ͕ߦͬ

͢Δͱ͍͏͜ͱΛҙຯ͢Δɻ೔ຊάϧʔϓ͸͜ͷ໰୊Λ͖ͯͨʮ͜Ε·ͰʯͷཅΠΦϯήʔτ૷ஔͷ‫ڀݚ‬։ൃʹղܾ͢ΔͨΊʹɼ͞Βʹ։‫཰ޱ‬Λ্͛ΔͳͲͷ GEM ‫ܕ‬͍ͭͯ঺հ͢ΔɻήʔτͷϞσϧͷ࠶‫ݕ‬౼͕ඞཁʹͳͬͨɻ

2.1

GEM ‫ܕ‬ήʔτϓϩτλΠϓ

2007 ೥ࠒ͔Β೔ຊάϧʔϓ͸ɼ༗‫ݶ‬ཁૉ๏ʹΑΔి৔
‫ࢠిͱࢉܭ‬ͷ༌ૹγϛϡϨʔγϣϯ4 Λߦ͍ͳ͕Β GEM‫ܕ‬ήʔτͷϞσϧͷ‫ݕ‬౼Λ࢝ΊͨɻGEM ݀ͷ௚‫ܘ‬Λ޿͛։‫཰ޱ‬Λ͋͛ͨํ͕ɼిࢠ͕ GEM ݀ʹೖΓ΍͘͢ͳΔ
ͷͰɼେ෯ʹిࢠಁա཰͸্ঢ͢Δɻ։‫཰ޱ‬Λ্͛Δͩ
͚Ͱͳ͘ɼGEM ͷް͞Λബͨ͘͠৔߹ʹ͸ɼGEM ݀ͷଆ໘ʹ͍ۙ৔ॴͷి৔͕‫ͳ͘ڧ‬Γɼి‫ྗؾ‬ઢ͸ GEM ݀಺ʹ޲͔͏޲͖ʹ࡞ΒΕΔͷͰɼGEM ݀ͷଆ໘΍ GEM
ͷද໘ʹ౸ୡͯ͠͠·͏ిࢠΛ‫ݮ‬Β͢͜ͱ΋Ͱ͖Δɻྫ͑͹ඪ४తͳ GEM ͷϞσϧͰɼઈԑମ෦Λ 50 µm ͔Βਤ 6: GEM ‫ܕ‬ήʔτϓϩτλΠϓΛ༻͍ͯߦΘΕͨి

25 µm ʹബͨ͘͠৔߹ɼిࢠಁա཰Λ͓͓Αͦ 50%ճࢠಁա཰ଌఆͷ݁Ռɻ਺ V ͷిѹ‫࠷Ͱڅڙ‬େಁա཰͸

෮ͤ͞Δ͜ͱ͕Ͱ͖Δɻಋମ෦΋ಉ༷ʹബͨ͘͠৔߹

։‫ͱ཰ޱ‬ಉఔ౓ͷ 60 %લ‫ͳͱޙ‬Δɻ

ʹ͓͍ͯ΋ɼGEM ಋମ෦ଆ໘ʹ‫ؼ‬ண͢Δి‫ྗؾ‬ઢΛ‫ݮ‬ΒͤΔͷͰɼిࢠಁա཰Λճ෮ͤ͞Δ͜ͱ͕Ͱ͖ΔɻҎ্ͷΑ͏ͳ݁ՌΛ౿·͑ɼ‫ͯ͠ྗڠʹۀا‬΋Β͍ɼඪ४

GEM Ϟσϧ͔Β։‫཰ޱ‬Λ্͛ɼ֨ஈʹബ͍ GEM αϯ

2.2ཁ‫͞ٻ‬ΕΔిࢠಁա཰

೔ຊάϧʔϓ͕༻͍͍ͯΔ TPC ୺෦‫ݕ‬ग़‫ث‬͸ 100 µm

ϓϧΛ࡞੒ͨ͠ʢਤ 5 ࠨ͸݀‫ ܘ‬90 µm, ઈԑ෦ 14 µm,

ްͷ 2 ૚ͷ૿෯ GEM Ͱߏ੒͞Ε͍ͯΔɻGEM ‫ܕ‬ήʔ

ಋମ෦ 2 µm, ϐον 140 µm ͷࣸਅʣɻ͜ͷॳ‫ظ‬αϯϓτͷϞσϧͷ‫ݕ‬౼ͱಉ࣌ฒߦͰɼ೔ຊάϧʔϓ͸ 2 ૚ͷϧͷੑೳධՁͷͨΊʢ࣮ࡍͷͱ͜Ζɼ࠷େͷ໨త͸ଌఆ૿෯ GEM ͔ΒͳΔ୺෦‫ݕ‬ग़‫ͲͰ͚ͩث‬Ε΄ͲͷҐஔ෼஋͕γϛϡϨʔγϣϯΛ࠶‫͢ݱ‬Δ͔Ͳ͏͔ͷ֬ೝͰ͋ͬ

ղೳΛಘΔ͜ͱ͕Ͱ͖Δ͔ɼ·ͨ ILC-TPC ͱͯ͠ཁ‫ٻ‬ͨʣɼKEK ͷ௿Թ޻ֶηϯλʔʹઃஔ͞Ε͍ͯΔ௒఻͞ΕΔੑೳΛຬͨ͢͜ͱ͕Ͱ͖Δͷ͔Ͳ͏͔Λௐ΂ΔͨಋιϨϊΠυϚάωοτΛ༻͍ɼT2K Ψεɼ1 T ͷߴΊʹɼ਺ճʹ࿱ΓυΠπɾDESY ‫ࢠిͰॴڀݚ‬ϏʔϜΛ༻͍ͨࢼ‫ݧ‬Λߦ͖ͬͯͨɻ

4 ౰࣌͸ Maxwell 3D ͱ Garfield8 Λར༻5

ILC-TPC ༻ͷଌఆ‫ิީث‬ͷੑೳΛ͔֬ΊΔͨΊʹ͸ߴ࣓৔ԼͰߴΤωϧΪʔిࢠϏʔϜ͕࢖͑Δ‫͕ڥ؀‬ඞཁͰ͋ΓɼDESY ‫ʹॴڀݚ‬͸͜ͷ TPC ͷੑೳࢼ‫ݧ‬ͷͨΊʹඞཁͱ͞ΕΔେ‫ܕ‬ϓϩτλΠϓϞδϡʔϧʢLPʣͱ௒఻ಋιϨϊΠυϚάωοτʢPCMAGʣɼ·ͨ‫ڞ‬௨ͷ

σx [mm]

223
0.3
0.25

- Neff = 28.5

0.05
0
0

‫ࣜݱ‬͸Α͘஌ΒΕ͓ͯΓɼ؆қతͳ৔߹Ͱ͸ҎԼͷΑ͏

σrφ (Z) =- Cd = 30 µm/ cm (E = 230V/cm, B = 3.5T)

0.1

TPC ͷҐஔ෼ղೳͷ௕‫཭ڑ‬υϦϑτͰͷ઴ۙతͳද

Cd2
σ02 +
·Z
Nef f

- σPRF = 0.260 mm- Polyaθ = 0.5

0.15಺ͷ֤άϧʔϓ͸‫ڞ‬௨ͷ‫ڥ؀‬Λ࢖ͬͯɼҐஔ෼ղೳ౳ͷͳ̎ͭͷ߲Ͱද‫͞ݱ‬ΕΔ5 ɻ!

- Ar:CF4:iC4H10 = 95:3:2- Finite pad width = 1.15 mm

0.2ಡΈग़͠ΤϨΫτϩχΫε͕ઃඋ͞Ε͍ͯΔɻLC-TPC‫ج‬ຊੑೳͷ࣮ূࢼ‫ݧ‬Λߦ͍ͬͯΔɻ

• Extrapolation to 3.5T based on 1.0T data

500

1000

1500

2000

Drift Length [mm]
ਤ 7: ిࢠϏʔϜࢼ‫ݧ‬σʔλʹ‫֎͍ͯͮج‬ૠ͞Εͨ 3.5 T(3)σrφ ͸ํҐ֯ (rφ) ํ޲ʹ͓͚ΔҐஔ෼ղೳɼୈ 1 ߲ σ0 ͸υϦϑτ‫ʹ཭ڑ‬ґΒͳ͍ఆ਺߲ɻCd ͸֦ࢄఆ਺ɼNef f͸ଌఆʹ‫د‬༩͢Δ༗ޮిࢠ਺ɼZ ͸υϦϑτ‫཭ڑ‬Λද͢ɻຊདྷͳΒ͹࣮‫͋Ͱڥ؀ػ‬Δ 3.5 T ͱ͍͏ߴ࣓৔ͰͷͰͷҐஔ෼ղೳʢήʔτͳ͠ͷ୺෦‫ݕ‬ग़‫ث‬ʣɻͯ͠-10 V ఔ౓Ͱ O(10−4 ) ͷཅΠΦϯ્ࢭ཰͕ಘΒΕ

Δ͜ͱ͕ࣔ͞ΕͨɻҰํͰਤ 8 ʹࣔ͢Α͏ʹɼैདྷͷ

GEM ͷΑ͏ͳ‫ؙ݀‬ϗʔϧͰ͸ɼϦϜ෯Λ‫͍ͬͯ͘͠ڱ‬ͯ΋໨ඪ։‫ʹ཰ޱ‬͸ಧ͔ͳ͍͜ͱ͕Θ͔ͬͨͷͰɼ໨ඪҐஔ෼ղೳΛධՁ͍͕ͨ͠ɼͦΕʹ߹͏࣮‫ڥ؀ݧ‬͸·։‫཰ޱ‬Λຬͨͨ͢Ίʹ࿡֯‫ܗ‬ͷϋχΧϜߏ଄ΛऔΔΑ͏ͩ੔උ͞Εͯͳ͍ͷͰɼ࣮ࡍʹ͸͜ΕΒͷύϥϝʔλΛͳ‫( ͨͬͳͱܗ‬ਤ 8)ɻ ͜͏ͯ͠࡞੒͞Εͨɼߴ։‫཰ޱ‬ͷ

1 T தͰͷ࣮‫ݧ‬ΑΓධՁ͠ɼ3.5 T ʹ֎ૠͯ͠Ґஔ෼ղೳΛಘΔ͜ͱʹͳΔɻୈ 2 ߲͸υϦϑτ‫ʹ཭ڑ‬ൺྫ͢Δ
ύϥϝʔλͰ͋ΔͷͰɼೖࣹిࢠϏʔϜҐஔΛมߋ͠ɼిࢠΛυϦϑτͤ͞Δ‫཭ڑ‬Λม͑ͯ‫཭ڑ‬ґଘͷଌఆΛߦ͍ܾఆ͢Δ΋ͷͰ͋Δɻਤ 7 Ͱࣔ͢Α͏ʹɼ2010 ೥ʹߦΘΕͨϏʔϜࢼ‫͍͓ͯʹݧ‬ɼ2 ૚ͷ૿෯ GEM Ͱߏ੒͞ΕΔ TPC ୺෦‫ݕ‬ग़‫ث‬ͷిࢠϏʔϜΛ༻͍࣮ͨ‫݁ݧ‬Ռ͔ΒɼGEM ‫ܕ‬ήʔτ͕౥ࡌ͞Εͳ͍৔߹Ͱ͸ɼ2.2 m
Ͱ͓͓Αͦ σrφ (σX ) =85 µm ఔ౓Ͱ͋Γɼ100 µm ҎԼͷҐஔ෼ղೳ͕ୡ੒͞Ε͍ͯΔɻిࢠಁա཰ͷ‫͔఺؍‬Βਤ 8: ԁߏ଄ɼϋχΧϜߏ଄ʹΑΔ౸ୡՄೳͳ‫ز‬Կֶత‫ݟ‬Δͱɼ100 µm ҎԼΛຬͨ͢ʹ͸ 80 %ఔ౓ͷಁա཰։‫཰ޱ‬ͷҧ͍ɻԁߏ଄Ͱ͸ 75 %ఔ౓͕‫ݶ‬քͱͳΔɻ͕ඞཁʹͳͬͯ͘Δ͜ͱ΋ࣔ͞ΕΔɻ
ࢼ࡞ GEM ‫ܕ‬ήʔτͷ֦େࣸਅΛਤ 9ɼϦϜͷஅ໘ͱ࣮2.3

ߴ։‫ ཰ޱ‬GEM ‫ܕ‬ήʔτͷ։ൃࡍͷ‫ݕ‬ग़‫ث‬αΠζͷϞδϡʔϧΛਤ 10 ʹࣔ͢ʢ݀ͷ಺઀ԁͷ௚‫ ܘ‬304 µmɼϐον 335 µm ޫֶ։‫ ཰ޱ‬82.3 %ʣɻ

૿෯ GEM ͚ͩΛ౥ࡌͨ͠ TPC ୺෦‫ݕ‬ग़‫ث‬ͷҐஔ෼

ਤ 10 ӈʹ͓͍ͯԿ΋͍ࣸͬͯͳΑ͏ʹ‫͑ݟ‬Δͱ͜Ζ͕ɼղೳͷ݁ՌΑΓɼ80 %ఔ౓ͷిࢠಁա཰͕ཁ‫͞ٻ‬ΕΔ

࣮ࡍʹ GEM ͕݀։͚ΒΕ͍ͯΔ༗‫ྖײ‬ҬͰ͋Δɻ͜ͷ͜ͱ͕ࣔ͞Εͨɻ·ͨॳ‫ظ‬αϯϓϧΛ༻͍ͨଌఆΑΓɼ

GEM ‫ܕ‬ήʔτͷੑೳΛ͔֬ΊΔͨΊɼ10×10 cm2 ͷ

T2K ΨεΛ༻͍ͨߴ࣓৔தͰ͸ɼಁա཰͸։‫ͱ཰ޱ‬ಉఔࢼ࡞඼Λ࡞੒͠࠶౓ KEK ͷϚάωοτΛ༻͍ͯߴ࣓৔

౓ͱͳΔ͜ͱ΋ࣔ͞Ε͍ͯΔɻҎ্ͷ͜ͱ͔ΒɼࠤլେԼͰଌఆͨ͠ిࢠಁա཰ͷ݁ՌΛਤ 11 ʹࣔ͢ɻ੨ͷ఺ɼֶΛத৺ʹ‫ۀا‬ʢϑδΫϥʣͱ‫ ͍͠৽ͯ͠ྗڠ‬GEM ‫ܕ‬࣮ઢ͸ͦΕͧΕిࢠಁա཰ͷ࣮ࡍͷଌఆ஋ɼϞσϧΛ༻ήʔτͷϞσϧͷ࠶‫ݕ‬౼Λߦͬͨɻ໨ඪ։‫཰ޱ‬͸ 80 %ఔ͍ͨγϛϡϨʔγϣϯ6 ͷ݁ՌΛද͢ɻ0 T ʹ͓͍ͯ͸γ

౓Ͱ͋Δ͕ɼྡΓ߹͏݀ͷϐον͕୹͗͢Δͱٕज़తʹϛϡϨʔγϣϯ͸ଌఆΛ࠶‫͍ͯ͠ݱ‬Δɻᒵ৭ͷ఺͸ 1 T೉͘͠ͳͬͯ͘Δɻ࠶౓γϛϡϨʔγϣϯΛ༻͍ͯ‫ݕ‬౼ͷ࣓৔தͰଌͬͨిࢠಁա཰Ͱ͋ΔɻVgate =3 V લ‫ޙ‬

ͨ͠ͱ͜Ζ [11]ɼϐον 300 µm ఔ౓Ͱ͋Ε͹ɼґવͱͰಁա཰ 82 %લ‫ͳʹޙ‬Δࣄ͕ࣔ͞ΕΔ͍ͯΔɻಉ༷ʹᒵ৭ͷ࣮ઢ͸ 1 T ԼͰͷγϛϡϨʔγϣϯͷ݁ՌΛද͠

5 ‫ݕ‬ग़‫͚͓ʹ཭ڑۙث‬ΔϗυείʔϓޮՌ΍ɼಡΈग़͠ύουߏ଄ͷӨ‫ڹ‬Λߟྀ͍ͯ͠ΔΑΓ‫׬‬શͳৼΔ෣͍Λද‫͢ݱ‬Δ͕ࣜ͜Ε·Ͱʹཧղ͞Ε͓ΓɼੑೳධՁͷͨΊͷߴ࣓৔΁ͷ֎ૠ͸ͦͪΒͰߦ͏ඞཁ
͕͋Δ [14]ɻ

͍ͯΔɻ‫ࡏݱ‬ͷͱ͜Ζߴ࣓৔ԼͰͷγϛϡϨʔγϣϯ͸
6 ͜͜Ͱ༻͍͍ͯΔιϑτ΢ΣΞ͸ɼANSYS ͱ Garf ield++ Ͱ

͋Δɻ

6
224

ͨɻࠓճͷ࣮‫ݧ‬ͷ࠷େͷ໨త͸ɼGEM ‫ܕ‬ήʔτΛ౥ࡌͨ͠‫ݕ‬ग़‫ͯ͠ͱͨͬ͋Ͱث‬΋ిࢠυϦϑτ‫ ཭ڑ‬2.2 m Ͱɼ
100 µm ҎԼͷҐஔ෼ղೳ͕ୡ੒ՄೳͰ͋Δͱ͍͏ূ໌
σʔλΛऩू͢Δ͜ͱͰ͋Δɻ

3.1

DESY-II Ճ଎‫ث‬ਤ 9: ԁߏ଄ʢࠨʣͱϋχΧϜߏ଄ʢӈʣΛϞσϧʹ࡞੒͞Εͨࢼ࡞ GEM ‫ܕ‬ήʔτͷ֦େਤɻਤ 12: DESY-II Ճ଎‫ث‬Λ༻͍ͨςετϏʔϜΤϦΞͷ
ུ֓ਤ [15]ɻ
ਤ 10: ߴ։‫ ཰ޱ‬GEM ‫ܕ‬ήʔτͷஅ໘ਤͱ TPC ୺෦‫ݕ‬ग़‫༻ث‬Ϟδϡʔϧɻ࣮ଌఆΛ‫׬‬શʹ͸࠶‫͍ͳ͍ͯ͠ݱ‬ɻ3.5 ͋Δ͍͸ 4 T Ͱͷిࢠಁա཰Λਪఆ͢ΔͨΊʹ͸ɼ͞ΒͳΔվળ͕ඞཁ
ͳঢ়‫͋Ͱگ‬Δɻਤ 13: TPC ੑೳࢼ‫ݧ‬ઃඋͷͨΊʹ௒ిಋιϨϊΠυϚ
άωοτ͕ஔ͔Εͨࢼ‫ݧ‬ΤϦΞɻ‫ݕ‬ग़‫ث‬ͷੑೳࢼ‫ʹݧ‬͸ DESY-II Ճ଎‫͔ث‬ΒͷిࢠϏʔϜΛ༻͍Δ (ਤ 12)ɻDESY-II Ճ଎‫ʹ಺ث‬͸ࡉ͍୸ૉણҡ͕ஔ͔Εɼిࢠ͋Δ͍͸ཅిࢠ͕୸ૉણҡΛଧͭ͜ͱͰ੍ಈ์ࣹʹΑΓޫࢠ͕ੜΈग़͞ΕΔɻ͜ͷޫࢠΛۚଐඪతͰిࢠཅిࢠͷϖΞʹίϯόʔτ͠ɼμΠϙʔϧ࣓ੴͰ͜ΕΒͷཻࢠΛઔ‫͛޿ʹܗ‬ɼిࢠΛΤωϧΪʔਤ 11: ߴ։‫( ཰ޱ‬82.3 %) ͷ GEM ‫ܕ‬ήʔτΛ༻͍ͨి͝ͱʹ෼ྨ͢Δɻͦͷ‫ޙ‬ίϦϝʔλͰϏʔϜΤϦΞ (ਤࢠಁա཰ͷଌఆ [12]ɻ࣓৔ͳ͠Ͱ͸γϛϡϨʔγϣϯ͸13) Ͱ࢖༻͢ΔͨΊͷϏʔϜΛબ୒͢ΔɻDESY-II ͸ଌఆΛ࠶‫͍ͯ͠ݱ‬Δɻ1 T ͰͷධՁ͸վળ͕ඞཁͳঢ়‫گ‬

1 ͔Β 5 GeV ఔ౓ͷΤωϧΪʔͷిࢠΛ‫͖Ͱڅڙ‬Δ͕ɼ

Ͱ͋Δɻ

TPC ֎นͷϑΟʔϧυέʔδͳͲͷ෺࣭தͰͷిࢠͷࢄཚͷӨ‫ڹ‬Λ‫ݮ‬Βͨ͢Ίʹɼଌఆʹ͸ 5 GeV ͷߴΤωϧΪʔిࢠϏʔϜΛ༻͍Δɻ

3

DESY ͰͷిࢠϏʔϜςετ
LC-TPC άϧʔϓʹࢀՃ͢Δ೔ຊͷ֤େֶɼதࠃͷ

IHEP ‫ॴڀݚ‬ͷ‫ऀڀݚ‬Λ‫ؚ‬Ίͨ೔ຊ/ΞδΞάϧʔϓ͸ɼ
2016 ೥ 10 ݄຤͔Β 11 ݄த०·ͰɼDESY ‫ॴڀݚ‬ͷ
TPC ੑೳࢼ‫ݧ‬ઃඋΛ࢖͍ɼ։ൃ͖ͯͨ͠ߴ։‫ ཰ޱ‬GEM‫ܕ‬ήʔτ͕౥ࡌ͞Εͨ TPC ୺෦‫ݕ‬ग़‫ث‬ͷੑೳࢼ‫ݧ‬Λߦͬ

3.2

ੑೳࢼ‫ݕ༻ݧ‬ग़‫ث‬ੑೳଌఆʹ͸ɼILD-TPC Ͱ༧ఆ͞Ε͍ͯΔ࣮‫ػ‬αΠζͷ૷ஔΛ༻͍Δ (ਤ 14)ɻ୺෦‫ݕ‬ग़‫ث‬ͷ PC Ϙʔυ͸ઔ‫ܕ‬ͷߏ଄Λ͍ͯ͠ΔɻPC Ϙʔυ্෦΁ͷ 2 ஈ૿෯ GEMɼ͓Αͼ GEM ‫ܕ‬ήʔτΛ‫ݻ‬ఆ͢ΔͨΊɼ·ͨ H.V. ‫څڙ‬

7
225

Ͱ͋Δɻ্ड़ͨ͠୺෦‫ݕ‬ग़‫ث‬ͷ PC Ϙʔυͷཪ໘͔ΒΧϓτϯέʔϒϧ͕ Front End Card(FEC) ʹ઀ଓ͞Εɼ͜ͷ FEC ্ʹ PASAɼALTRO νοϓ͕౥ࡌ͞Ε͍ͯ
ΔɻALTRO νοϓ͸ 20(25) MHz, 10 bit ͷ ADC ͕࢖༻͞Ε͓ͯΓɼϖσελϧิਖ਼ɼθϩαϓϨογϣϯ
ͳͲͷ‫ػ‬ೳ͕࢖༻ՄೳͰ͋ΔɻಡΈग़͠ΤϨΫτϩχΫ
εΛ઀ଓ͠ऴ͑ͨঢ়‫͕ࣸگ‬ਅ (ਤ 15) ͷΑ͏ʹͳΔɻΤϨΫτϩχΫε͕ಥ͖ग़ͨ֨޷ͷͨΊࢧ࣋ߏ଄͕ඞཁͱͳ͍ͬͯΔ͕ɼॾʑͷ໰୊Λճආ͢ΔͨΊຊདྷ PASAɼALTRO νοϓ͸ PC Ϙʔυͷཪ໘ʹ௚઀౥ࡌ͞ΕΔ΂
͖Ͱ͋Δɻ࢒೦ͳ͕Βվྑνοϓͷ։ൃ͸஗Ε‫ؾ‬ຯͰ͋Δɻਤ 14: ࠨਤ্͸ TPC ୺෦‫ݕ‬ग़‫ث‬ͷಡΈग़͠ύουɻӈਤ্͸೔ຊάϧʔϓ͕༻͍͍͍ͯΔ 2 ૚૿෯ GEM ͷଆ໘ࣸਅͰ͋Δɻ͜ͷ্෦ʹҎԼͷΑ͏ͳ௥ՃϞδϡʔϧ͕౥ࡌ͞ΕΔɻࠨਤԼ͸ి৔੔‫͕ثܗ‬౥ࡌ͞Εͨ‫ݕ‬ग़‫ث‬ɼલ໘͓Αͼଆ໘͸ి৔Λ‫ۉ‬Ұʹ‫ܗ‬੒͢ΔͨΊʹి‫ۃ‬͕औΓ෇͚ΒΕɼద੾ͳిҐ͕༩͑ΒΕΔΑ͏ʹͳͬͯ
͍ΔɻӈਤԼ͸ GEM ‫ܕ‬ήʔτ͕౥ࡌ͞Εͨ‫ݕ‬ग़‫ث‬ɻϥΠϯ༻ͷͨΊͷҰ෦ͷεϖʔεΛ࢒ͯ͠΄΅શ໘ɼಡΈग़͠ύουͰ෴ΘΕ͍ͯΔɻύου 1 ຕͷେ͖͞͸͓͓Αͦɼ෯ 1.2 mm ॎ 5.26 mm Ͱ͋Γɼԁ౵ (r) ํ޲ʹ

28 ྻɼํҐ֯ (φ) ํ޲ʹ಺ଆ 176 ຕɼ֎ଆ 192 ຕ͕഑ஔਤ 15: ‫ݕ‬ग़‫ث‬Λ TPC ʹ૊ΈࠐΜͩ‫ޙ‬ɼಡΈग़͠ΤϨ͞Ε͍ͯΔɻ1 ‫ݕ‬ग़‫ͨ͋ث‬Γɼ5×103 νϟϯωϧఔ౓ͱΫτϩχΫεΛ౥ࡌͨ͠ঢ়ଶɻ͜ͷ‫͞ޙ‬ΒʹΤϨΩ༻ʹ

7

ͳΔɻ2 ஈ૿෯ GEM ͷ 9 mm ্෦ ʹ͸։ൃ͖ͯͨ͠

L.V. έʔϒϧͳͲ͕લ໘ʹ౥ࡌ͞ΕΔɻ։‫ ཰ޱ‬80 %Ҏ্ͷ GEM ‫ܕ‬ήʔτ૷ஔ͕౥ࡌ͞ΕΔɻ։‫ ཰ޱ‬100 %ͷσʔλͱͷൺֱͷͨΊɼGEM ‫ܕ‬ήʔτ૷ஔͷ୅ΘΓʹి৔੔‫͕ثܗ‬౥ࡌ͞Εͨ‫ݕ‬ग़‫ث‬΋༻ҙͨ͠ɻ૿෯ GEMɼGEM ‫ܕ‬ήʔτʹిѹΛ‫͢څڙ‬Δͨ
ΊɼH.V. ϥΠϯ͸ GEM ͷΞΫςΟϒΤϦΞͷۙ͘·Ͱ৳͹͢ඞཁ͕͋Δ͕ɼ͜Ε͸૿෯ GEM ্෦ͷυϦϑτྖҬͷి৔Λ࿪ΊΔͷͰి཭ిࢠͷ‫ܦ‬࿏Λ࿪ΊΔ͜ͱʹͳΔɻ͜ͷঢ়‫گ‬Λվળ͢ΔͨΊʹి৔੔‫ثܗ‬Λ༻͍ͯ‫׈‬Β͔ͳి৔Λ࠶‫ܗ‬੒ͤ͞Δɻ࣮ࡍͷͱ͜ΖɼGEM‫ܕ‬ήʔτͷଆ໘ʹ΋ి৔੔‫༻ثܗ‬ͷճ࿏Λ‫ܗ‬੒͢Δ༧ఆ
͕ͩͬͨɼ͜ͷ෦෼͸ࠓճͷϏʔϜςετʹ͸ؒʹ߹Θ
ͳ͔ͬͨɻ

3.3

ಡΈग़͠ΤϨΫτϩχΫε

3.4

࣮‫ݧ‬४උͱσʔλऩूա‫਺ڈ‬ճͷϏʔϜςετͷ‫͔ݧܦ‬Βࣄલ४උ͕؊৺Ͱ
͋Δ͜ͱΛֶΜͰ͍ͨͷͰɼKEK ࣮‫ݧ‬౩Ͱ࢖༻༧ఆͷ૿෯ GEM ͱ GEM ‫ܕ‬ήʔτΛ༻͍ͯɼͲΕ͚ͩͷిѹΛ‫͢څڙ‬Ε͹ͲΕ΄ͲͷΨε૿෯཰ΛಘΒΕɼͲ͔͜Βඍখ์ి͕࢝·Δ͔ɼ·ͨͲͷఔ౓ͷిѹͰ࠷େಁա཰ΛಘΒΕΔ͔ͳͲͷࣄલଌఆΛೖ೦ʹߦ͔ͬͯΒɼDESYʹ޲͔ͬͨɻσʔλऩू͸ 10 ݄ 31 ೔ΑΓ 11 ݄ 14 ೔·Ͱɼ͓Αͦ 2 िؒʹΘͨͬͯߦͬͨɻ࠷ॳͷ਺೔͸ LP
γεςϜ‫ؚ‬Ίͨ‫ݕ‬ग़‫ث‬ͷࢼӡసͱͯ͠ɼϊΠζ֬ೝ΍‫ݕ‬ग़‫ث‬ͷԠ౴ଌఆͳͲ‫ૅج‬తͳσʔλͷऩूΛߦͬͨɻͦ
ͷ‫ޙ‬ɼߴ࣓৔தͰͷҐஔ෼ղೳͷධՁ༻ʹɼ‫ݕ‬ग़‫͔ث‬Β

DESY ʹઃஔ͞Ε͍ͯΔ LP γεςϜͰ༻͍ΔಡΈग़ͷిࢠϏʔϜͷ‫཭ڑ‬Λม͑ɼి཭ిࢠͷυϦϑτ‫཭ڑ‬Λ͠ΤϨΫτϩχΫε͸ɼALICE-TPC [16] Ͱ༻͍ΒΕͯม͑ͳ͕Βσʔλऩू (Z ํ޲εΩϟϯ) Λߦͬͨɻ·͍ͨΔγεςϜʮALTRO [17]ʯΛ‫ج‬ຊͱ͓ͯ͠Γɼిՙ

GEM ‫ܕ‬ήʔτ૷ஔ͕‫ظ‬଴͢ΔΑ͏ʹಈ࡞͍ͯ͠Δ͔ͷ૿෯ɼ೾‫ܗ‬੔‫ܗ‬෦ (PASA) Λ GEM ༻ʹ࡞Γม͑ͨ΋ͷ֬ೝͷͨΊɼGEM ‫ܕ‬ήʔτؒʹ͔͚ΔిѹΛม͑ͨଌ

7 9 mm ্෦ͱ͍͏ͷ͸ɼILC ϏʔϜͷτϨΠϯ௕Ͱܾ·Δɻ૿෯ GEM ͱήʔτ૷ஔͷؒʹ͸‫ٵ‬ऩલͷ 2 ࣍ΠΦϯ͕ଘࡏ͢ΔɼτϨΠϯ௕͸ઃ‫ ্ܭ‬0.73 msec ఔ౓ͳͷͰɼ5 mm ఔ౓্෦Ͱे෼͔
΋͠Εͳ͍͕ɼ͜ͷ෦෼͸ٞ࿦ͷ༨஍͕͋ΔͱࢥΘΕΔɻ

ఆ΋ߦͬͨɻཉ͍͠σʔληοτ͸ࣄલʹ͋Δఔ౓ܾΊͯߦ͕ͬͨɼϏʔϜλΠϜ͸‫ݶ‬ΒΕ͍ͯΔͷͰɼ࠷ऴత
ʹ͸‫ݱ‬৔ͰσʔλΛऔΓͳ͕Βɼ؆қղੳΛߦ͍ɼ݁Ռ

8226Λ‫͕ͳݟ‬Βࠓ‫ޙ‬ͷํ਑ΛܾΊ͍ͯͬͨΑ͏ʹࢥ͏ɻ޾͍

͜ͷ஋͸খ‫ܕ‬αϯϓϧΛ༻͍ͨ 1 T தͰͷిࢠಁա཰ଌ

ͳ͜ͱʹɼϏʔϜςετ‫ؒظ‬த΄΅େ͖ͳτϥϒϧʹ͸

ఆͷ࠷େಁա෇ۙʹҰக͠ɼ͓͓Αͦ 82 %͕ಘΒΕΔ

ऻΘΕͣɼॱௐʹσʔλऩूΛߦ͏͜ͱ͕Ͱ͖ɼ༧ఆΑͱ‫ظ‬଴Ͱ͖Δɻ(ਤ 17) ӈ͸ GEM ‫ܕ‬ήʔτΛ౥ࡌͨ͠Γ΋ 1 ೔ૣ࣮͘‫ݧ‬Λऴྃͤͨ͞ɻDESY Ͱऩूͨ͠ 1 T‫ݕ‬ग़‫ిͱث‬৔੔‫ثܗ‬Λ౥ࡌͨ͠‫ݕ‬ग़‫ͱث‬ͷ MPV ͷ஋ͷ࣓৔தʹ͓͚Δࣄ৅ྫΛਤ 16 ʹࣔ͢ɻ

ൺֱͰ͋Δʢ‫͔ͭز‬ͷϨΠϠʔͷฏ‫ۉ‬஋ʣɻશυϦϑτ‫ʹ཭ڑ‬ରͯ͠‫ظ‬଴͢Δ 82 %ͷ‫ݮ‬গ͕֬ೝͰ͖ΔɻҐஔਤ 17: શυϦϑτ‫ ͯؔ͠ʹ཭ڑ‬2 ୆ͷ‫ݕ‬ग़‫Ͱث‬औΒΕਤ 16: ෺ཧղੳʹ༻͍͸͠ͳ͍͕ɼిࢠ͕֎นͰγϟϫʔΛ‫ͨ͜͠ى‬৔߹ͷΠϕϯτɼ࣓৔தͰ͋ΔͷͰɼ௿ΤωϧΪʔՙిཻࢠ͕Χʔϧ͍ͯ͠Δ༷ࢠ͕Θ͔Δɻ

ͨ MPV ஋ͷൺɻ෼ղೳࣜͷதͷύϥϝʔλ Nef f Λ༻͍Δ͜ͱʹΑͬͯ΋ GEM ‫ܕ‬ήʔτͷಈ࡞֬ೝ͸ߦ͑ΔɻNef f ͸ੜ੒͞Εͨి཭ిࢠ਺ N ʹ͓͓Αͦൺྫ͢ΔͷͰɼNef f ͷ

3.5‫͔ͭز‬ͷσʔλղੳൺֱ͔Βిࢠಁա཰ΛධՁͰ͖ΔɻGEM ‫ܕ‬ήʔτʹҹՃ͢ΔిѹΛม͑ͯ Z ํ޲εΩϟϯΛߦ͍ɼҐஔ෼ղ͜ͷχϡʔεͷ‫ߘݪ‬Λॻ͍͍ͯΔ 12 ݄‫ࡏݱ‬ɼσʔλೳࣜͰϑΟοτͯ͠ Nef f ͷύϥϝʔλΛ‫ੵݟ‬΋ͬͨ݁ղੳΛ࢝Ίͨ͹͔ΓͰ͋Γɼσʔλͷଟ͘͸ະͩे෼ՌΛਤ 18 ʹࣔ͢ɻਤͰ͸ +3.55 V ͷͱ͖ͷ N ͓Αͼʹཧղ͍ͯ͠Δঢ়‫Ͱگ‬͸ͳ͍ɻ‫ࡏݱ‬ಘΒΕ͍ͯΔ݁Ռ

Nef f Λ 1 ͱ‫֨ن‬Խ͍ͯ͠Δɻ55 Fe ઢ‫ݯ‬Λ༻͍ͨ KEK

͸ Preliminary ͳ΋ͷͰ͋Δ͕ɼࠓճ։ൃͨ͠ GEM ‫ܕ‬ʹ͓͚Δࣄલଌఆͷ݁Ռ͔Βɼ+3.55 V → +0.00 V ͷήʔτΛ౥ࡌͨ͠‫ݕ‬ग़‫͕ث‬ɼզʑͷ‫ظ‬଴௨Γʹಈ͍͍ͯมԽͰ ಁա཰ 25 % ఔ౓ͷ‫ݮ‬গɻ+3.55 V → −3.55 VΔࣄΛද͢ϓϩοτɼߴ࣓৔ 3.5 T தͰ౸ୡ͠ಘΔͱ

ͷมԽͰ ಁա཰ 65 % ఔ౓ͷ‫ݮ‬গ͕‫ظ‬଴͞ΕΔ͕ɼՙ‫ظ‬଴Ͱ͖ΔҐஔ෼ղೳΛද͢ϓϩοτͳͲΛࣔ͢͜ͱʹిཻࢠΛ༻͍ͯಘΒΕΔ݁Ռ͔Β΋ಉ༷ͷมԽ͕֬ೝͰ

͢Δɻ

͖Δɻ

3.5.1

ՙిཻࢠʹର͢Δ GEM ‫ܕ‬ήʔτͷಈ࡞‫ݕ‬ग़‫ث‬Πϯετʔϧ‫ޙ‬ͷ 1 ͭͷ৺഑ࣄ͸ɼGEM ‫ܕ‬ήʔτ͕‫ظ‬଴͍ͯ͠ΔΑ͏ʹಈ࡞͍ͯ͠Δ͔ͱ͍͏ࣄͰ
͋Δɻਤ 10 Ͱࣔͨ͠Α͏ʹɼ։‫ ཰ޱ‬82 %ͷ GEM ‫ܕ‬ήʔτͷް͞͸ 25 µm ఔ౓Ͱ͋ΓɼϦϜ෯΋ 30 µm ఔ౓Ͱ͋ΔͷͰɼจࣈͲ͏ΓͷϖϥϖϥͷεΧεΧঢ়ଶͰ͋Δɻ࠷େ‫ݶ‬஫ҙͯ͠ѻͬͯ͸͍Δ͕ɼ‫ݕ‬ग़‫ث‬ͷΠϯετʔϧதɼ͋Δ͍͸ॳΊͯߴిѹΛҹՃͨ࣌͠ʹɼৼಈ΍ඍখͳνϦΛ͖͔͚ͬʹ GEM ‫ܕ‬ήʔτͷҰ෦͕୹བྷͯ͠͠·͏Մೳੑ͕͋Δɻ͔͠͠ɼGEM ‫ܕ‬ήʔτ͸୹བྷͨ͠৔߹Ͱ΋ 70 %͍ۙಁա཰ͷͨΊʢ࣓৔ͳ͠࠷େ
ಁա 85 %ఔ౓ͱൺֱͯ͠΋ʣɼҰ‫ʹݟ‬ਖ਼ৗಈ࡞͍ͯ͠

ਤ 18: GEM ؒిѹΛมߋͨ࣌͠ͷ༗ޮిࢠ਺ Nef fΔͷ͔൑அͮ͠Β͍ɻΑͬͯɼGEM ‫ܕ‬ήʔτ͕ࡌͬͯʢ੺ʣɼ͋Δ͍͸ి཭ిࢠ਺ N ʢࠇʣͷมԽʹ͍ͭͯɻ͍ͳ͍৔߹ͷిՙྔͱൺֱ͢Δ͜ͱ΍ɼిՙྔ͕࣮֬ʹ࣓৔ͳ͠Ͱͷଌఆ݁Ռɻ

มΘΔͱ͜Ζ·ͰήʔτΛดͯ͡ൺֱ͢Δඞཁ͕͋Δɻిՙྔͷൺֱʹ͸৴߸ిࢠΛ૿෯ͨ͠‫ޙ‬ͷిՙྔͷ෼෍ͷ MPV (Most Provable Value) Λ༻͍Δ (ਤ 17) ࠨɻ࣮‫ݧ‬த GEM ‫ܕ‬ήʔτʹҹՃ͍ͯͨ͠஋͸ 3.55 V Ͱ͋Δɻ

9227

Γେ͖͘ɼ͍ΘΏΔ Fermi plateau ʹҐஔ͠ɼMIP ʹൺࠓճͷిࢠϏʔϜςετͷ࠷େͷ໨త͸લड़ͷ௨Γɼʮ GEM ‫ܕ‬ήʔτΛ౥ࡌͨ͠‫ݕ‬ग़‫ث‬Λ༻͍ͯɼυϦϑτ‫ ཭ڑ‬2.2 m Ͱ΋Ґஔ෼ղೳ 100 µm ҎԼ͕ୡ੒Մೳʢ֎ૠʣͰ͋Δ͜ͱΛূ໌͢ΔσʔλΛͱΔɻʯͱ͍͏͜ͱ
Ͱ͋ͬͨɻ3.5 T ʹ֎ૠ͢ΔͨΊʹඞཁͳύϥϝʔλ͸ɼಡΈग़͠ύουͷߏ଄΍૿෯ GEM ͚ͩʹΑΔ৴߸ిՙͷ޿͕Γ͔Βܾ·Δ σ0 ɼΨεʹΑΔ֦ࢄͷӨ‫ڹ‬Λද͢

Cd (3.5 T ͱ 1.0 T)ɼͦͯ͠ ଌఆʹؔ༩͢Δ༗ޮిࢠ਺ Nef f Ͱ͋ΔɻGEM ‫ܕ‬ήʔτ૷ஔͷϑϨʔϜۙล͸ి৔੔‫૷͕ثܗ‬ண͞Ε͓ͯΒͣɼ‫ܗ‬੒͞ΕΔి৔ͷঢ়‫گ‬͕ෆಁ໌Ͱ͋Δɻࠓճͷใࠂʹ͓͍ͯɼҎԼʹࣔ͢Ґஔ෼ղೳͷղੳʹ͸தԝ෇ۙͷ͋Δ 1 ϨΠϠʔΛ༻͍ͨ΋ͷͰ͋Δʢ΋ͪΖΜ‫ݕ‬ग़‫ڥث‬ք෇ۙͷτϥοΫͷ࿪ΈͳͲΛ‫ݟ‬Δ৔߹ʹ͸ɼϑϨʔϜۙลͷσʔλ΋ҙຯͷ͋Δ
΋ͷͱͳΔɻ·ͨ‫ݕ‬ग़‫ث‬શମͷੑೳΛߟྀ͢Δ৔߹ɼ֤΂ଟ͘ͷి཭ిࢠΛൃੜͤ͞Δɻ(c) ͸ 5 GeV ిࢠͷ݁ՌΛ MIP ʹম͖௚ͨ͢Ίʹ Nef f ʹ 1/1.48 Λֻ͚ͨ΋ͷͰ͋Δɻ؆қղੳͰ͸͋Δ͕ɼ‫ࡏݱ‬ͷͱ͜ΖҐஔ෼ղೳ͸ 100 µm ΛԼճͬͨ݁Ռ͕ಘΒΕ͍ͯΔɻύϥϝʔλͷධՁʹؔͯ͠͞ΒʹղੳΛվળ͢Δඞཁ͕͋Δ͜ͱ͕Θ͔͍ͬͯΔͷͰɼ৴པͰ͖Δ࠷ऴ݁ՌΛ଴͍ͪͨͱࢥ͏ɻి৔੔‫͕ثܗ‬౥ࡌ͞Εͨ‫ݕ‬ग़‫ͱث‬ͷ Nef f ͷ஋ͱͷൺֱʹؔͯ͠͸ɼਤ 19 ΑΓ GEM ‫ܕ‬ήʔτ‫ݕ‬ग़‫ث‬Ͱ Nef f =25.0ɼి৔੔‫ݕثܗ‬ग़‫ Ͱث‬Nef f =29.1ɼมԽ
͸ 17 %ఔ౓ͱͳΓɼ͓͓Αͦ‫ظ‬଴͢ΔมԽ཰͕ࣔ͞Ε͍ͯΔɻ

σx [mm]‫ظ‬଴͞ΕΔҐஔ෼ղೳ

3.5.2

ϨΠϠʔͷҐஔ෼ղೳͷঢ়‫گ‬΋‫ݟ‬Δ΂͖Ͱ͋Δʣɻ

0.3• Extrapolation to 3.5T based on 1.0T data
- Ar:CF4:iC4H10 = 95:3:2- Finite pad width = 1.20 mm- (a) σPRF = 0.277 mm (2016 configuration) 5GeV
- (b) σPRF = 0.334 mm (2016 measure σPR(0)=481 µm) 5GeV
- (c) σPRF = 0.334 mm (2016 measure σPR(0)=481 µm) MIP- Polyaθ = 0.6- Cd = 27 µm/ cm (B = 3.5T)- Neff = 25

0.25
0.2
0.15

தԝ෇ۙͷ͋ΔϨΠϠʔʹରͯ͠ɼ৴߸ిՙͷ޿͕Γ͔

σx [mm]0.1

GeometricMean_Resolutin_Row38

0.18

0.05
σ0 = 63.1 ± 1.1 [µm]0CD/ Neff = 17.4 ± 0.15 [µm/ cm]

0.14

Prel

σ0 = 61.2 ±

1500

2000

MIP ʹର͢ΔҐஔ෼ղೳͷ༧૝஋ɻ

1 [µm]

CD/ Neff = 16.4 ± 0.15 [µm/ cm]

0
p1

1000

‫ʹݩ‬ɼ3.5 T ʹ֎ૠͨ݁͠ՌಘΒΕͨ 5 GeV ిࢠ͓Αͼ

Field Shaper

0.06

p0

500

ਤ 20: GEM ‫ܕ‬ήʔτ౥ࡌ‫ݕ‬ग़‫Ͱث‬ଌఆ͞ΕͨσʔλΛ

0.1
0.08

0

Drift Length [mm]

ry
imina

0.12

ary

Prelimin(b)

Gate GEM

0.16

χ2 / ndf(c) Neff * 1/1.4

(a)

100
5.128 / 7

χ 2 / ndf

200
27.24 / 7

0.06313 ± 0.001107

p0

0.06118 ± 0.001017

0.005516 ± 4.896e-05

p1

0.005176 ± 4.606e-05

300

400

500

Drift Length: Z [mm]

ਤ 19: 1 T ͷ࣓৔தͰଌఆ͞Εͨ GEM ‫ܕ‬ήʔτ౥ࡌ‫ݕ‬ग़‫ిͱث‬৔੔‫ثܗ‬౥ࡌ‫ݕ‬ग़‫ث‬ͷҐஔ෼ղೳͷҧ͍ɻΒ‫ੵݟ‬΋ΒΕͨ Cd ͸͓͓Αͦ 87ɼZ ํ޲εΩϟϯ͔ΒಘΒΕͨσʔλΛ༻͍ͯɼਤ 19 ͷΑ͏ʹҐஔ෼ղೳࣜ
ͰϑΟοτΛߦ͍ɼZ ํ޲ʹԊͬͯ Nef f Λಘͨɻ·ͨɼ

1 T ʹ͓͚Δ Cd =87 ΛγϛϡϨʔγϣϯ͔Β 3.5 T ʹ֎ૠ͢Δͱ Cd ͸͓͓Αͦ 27 ʹͳΔɻ͜ͷΑ͏ʹ‫ٻ‬ΊΒΕͨ Nef f ͓Αͼ Cd Λ༻͍ͯɼ1 T ͷ৚݅ԼͰଌఆ͞Ε4ཅΠΦϯ્ࢭ཰ͷධՁ
࢒Δ LC-TPC άϧʔϓͷ՝୊ͷҰͭͱͯ͠͸ɼ։ൃ͞Εͨߴ։‫ ཰ޱ‬GEM ‫ܕ‬ήʔτ૷ஔΛ༻͍ͯཅΠΦϯʹ
ର͢Δಁա્ࢭ཰Λ࣮ଌ͠ɼͦͷੑೳΛূ໌͢ΔࣄͰ͋
Δɻ͜Ε·Ͱ͸γϛϡϨʔγϣϯΛ༻્͍ͯࢭ཰Λ༧ଌ͖͓ͯͯ͠Γɼ-10 V ఔ౓Ͱ O(10−4 ) ͷ્ࢭ཰͕ཅΠΦϯʹରͯ͠‫ظ‬଴͞Ε͍ͯΔ [11]ɻࠓճɼKEK ࣮‫ݧ‬౩Ͱ

GEM ‫ܕ‬ήʔτ૷ஔΛ༻͍ͯཅΠΦϯʹର͢Δ્ࢭ཰ͷ࣮ଌΛߦͬͨɻ࣮ࡍͷͱ͜ΖཅΠΦϯ્ࢭ཰ଌఆ༻ͷಛผͳ‫ثػ‬͸ઃஔ͞Ε͍ͯͳ͍ͷͰɼిࢠͷ્ࢭ཰ΑΓཅͨҐஔ෼ղೳΛ 3.5 T ʹ֎ૠ͢Δͱɼਤ 20 ͷΑ͏ʹͳΠΦϯͷ્ࢭ཰ͷԼ‫ݶ‬஋Λ‫ੵݟ‬΋Δ͜ͱʹͳΔɻલड़ͷΔɻͨͩ͠ɼCd ͸Ψεͷঢ়‫گ‬ɼઃఆిѹʹΑΓେ͖͘ม௨ΓɼཅΠΦϯ͸ిࢠʹൺ΂ͯे෼ʹॏ͍ͨΊ֦ࢄͷӨಈ͢ΔͷͰɼCd ͷ஋ͷৄࡉͳධՁ͸ॏཁʹͳΔ͕ɼࠓ‫͕ڹ‬খ͘͞ɼΑΓి‫ྗؾ‬ઢʹԊͬͯಈ͘ࣄʹͳΔͷͰɼճ͸࣌ؒͷ౎߹্؆қతͳධՁ͚ͩΛߦ͍ͬͯΔ͜ͱΛిࢠͷ્ࢭ཰͕ཧղͰ͖Ε͹ɼཅΠΦϯͷ્ࢭ཰΋ͦͷิ଍͓ͯ͘͠ɻ(a), (b) ͸ͦΕͧΕ 5 GeV ిࢠʹΑΔ݁

Լ‫ͯ͠ͱݶ‬ಘΔࣄ͕Ͱ͖Δɻਤ 21 ࠇઢ͸࣮ࡍʹమઢ‫ݯ‬ՌΛ֎ૠͨ͠΋ͷͰ͋Δɻ2 ͭͷҧ͍͸ి‫ۃ‬ύουʹର΍ UV ϨʔβʔΛ༻͍ͯ৴߸ͷେ͖͞ͷൺ͔Βిࢠͷಁ͢Δిՙͷ޿͕ΓΛද͢ σP RF ʹߏ଄ͱిѹઃఆͰܾ·Δ஋Λ࢖༻͔ͨ͠ɼଌఆ஋Λ࢖༻͔ͨ͠Ͱ͋Δɻ5 GeVిࢠͷి཭ଛࣦ͸ MIP (Minimum Ionizing Particle) Αա્ࢭ཰ΛධՁͨ͠΋ͷͰ͋Δɻ-15 V Ͱ O(10−4 ) ఔ౓
8 1.4 ͱ͍͏஋͸ Heed[18] ʹΑΔి཭ଛࣦͷγϛϡϨʔγϣϯΛߦͬͯಘͨ΋ͷͰ͋Δɻ

10Electron Transmission

228

1

AvalancheMC (step 8µm)
AvalancheMicroscopic

10-1• Geometrical Parameters

10-2- Diele. 12.5µm / HolePitch 335µm

Measurement- UpCopp. 9.2µm / LwCopp. 2.8µm- UpRim. 27µm / LwRim. 31 µm-310ਤ 22: 2016 ೥ळɼϏʔϜςετࢀՃऀͨͪɻ

- Protrusions of Diele. 1 µm
- E-feild 230V/cm

10-4

-20

-15

-10

-5

0

5

10

15

20

Vgate [V]

ਤ 21: ήʔτ૷ஔʹ‫ిٯ‬ѹΛҹՃ͍ͯͬͨ͠৔߹ͷిࢠಁա཰ʢ> ཅΠΦϯ્ࢭ཰͕‫ظ‬଴Ͱ͖Δʣɻύϥϝʔλ͸γϛϡϨʔγϣϯʹ༻͍ͨϞσϧͷ஋ɻͷిࢠ્ࢭ཰͕ಘΒΕ͍ͯΔɻ͜Ε͸ྫ͑͹༗ޮΨεήΠϯ9 ͕ 3000 ఔ౓ͱԾఆͨ͠৔߹ɼ1 ‫ݸ‬ͷυϦϑτిࢠͰυϦϑτྖҬதʹ‫͢ྲྀٯ‬ΔཅΠΦϯ͸ 1 ‫ͳͱݸ‬Δɻి
ࢠͷ્ࢭ཰ʹؔ͢ΔγϛϡϨʔγϣϯͷ݁ՌΛ੨ɼ੺ઢͰද͍ͯ͠Δ͕ɼࠓͷॴσʔλͷ࠶‫ݱ‬͸Ͱ͖͍ͯͳ͍ɻ
དྷ೥౓ʹ͸࣮ࡍʹཅΠΦϯ્ࢭ཰ଌఆΛߦ͍ɼ਺ V ͷҹՃͰ્ࢭ཰ O(10−4) ͷূ໌Λߦ͏༧ఆͰ͋Δɻ࣮ࡍ͸૿෯ GEM ࣗମʹ΋ཅΠΦϯͷ‫ٵ‬ऩ࡞༻͕͋Γ O(10−2)͕‫ظ‬଴Ͱ͖ΔͷͰɼ΄ͱΜͲཅΠΦϯ͸‫͍ͳͯ͜͠ྲྀٯ‬ͱ‫ظ‬଴͞ΕΔɻਤ 23: ϏʔϜςετ‫ ͨͬߦʹؒظ‬GEM ‫ܕ‬ήʔτʹؔ͢ΔϫʔΫγϣοϓͷ‫ه‬೦ࣸਅɻࢀߟจ‫ݙ‬[1] https://www.linearcollider.org/ILC/Publications/TechnicalDesign-Report.

[2] http://www.linearcollider.org/ILC/physicsdetectors/Detectors/Detailed-Baseline-Design.

[3] ాล༑඙, ILC ͷ෺ཧ, ߴΤωϧΪʔχϡʔε 32 (2014) 247.
[4] ILC ೔ຊάϧʔϓ, ILC ͷ‫ݕ‬ग़‫ث‬, ߴΤωϧΪʔχϡʔε 335͜Ε͔Βͷ‫ڀݚ‬։ൃ
ILC-TPC ͷͨΊͷߴ։‫ ཰ޱ‬GEM ‫ܕ‬ήʔτͷ։ൃͱͯ͠͸ɼ΋ͪΖΜ‫͔ͭز‬ͷ௥Ճଌఆ΍૷ஔ౥ࡌͷͨΊͷ޻ֶઃ‫Ͳͳܭ‬͸࢒͍ͬͯΔ͕ɼ‫ۀا‬ͷଟେͳ‫ྗڠ‬΋͋Γɼͻͱ·ͣཁ‫ٻ‬ੑೳΛຬͨ͢ʢͱࢥΘΕΔ@12 ݄‫ࡏݱ‬ʣ૷ஔ͕‫׬‬੒ͨ͠ঢ়‫͋Ͱگ‬ΔɻILC-TPC ͷ࣮‫ݱ‬Λࠨӈ͢Δ‫ݕ‬ग़‫ث‬։ൃΛߦ͍ɼLC-TPC ίϥϘϨʔγϣϯʹ͓͍ͯ΋ॏཁͳ໾ׂΛՌͨͨ͠ͱࢥ͏ɻ‫ ࡏݱ‬LC-TPC ಺Ͱ͸υΠπɾϑϥϯεͷάϧʔϓ͕ͦΕͧΕͷσβΠϯʹ‫ ͍ͨͮج‬TPC ୺෦‫ݕ‬ग़‫ث‬Λ։ൃ͍ͯ͠Δ͕ɼࠓ‫Ͳޙ‬ͷάϧʔϓ΋զʑ͕։ൃͨ͠ߴ։‫ ཰ޱ‬GEM ‫ܕ‬ήʔτΛ౥ࡌ͠ɼੑೳࢼ‫ݧ‬Λߦ͏༧ఆͰ͋Δɻ·ͨ ILC-TPC ͕࣮‫ͨ͠ݱ‬৔߹ɼ֤άϧʔϓ͕౷߹͞Ε 1 ͭͷ‫ݕ‬ग़‫ث‬ΛσβΠϯ͢Δ͜ͱʹͳΔͱࢥΘΕΔɻGEM ‫ܕ‬ήʔτͷ։ൃͷաఔͰզʑ͕ಘͨ஌‫ݟ‬Λ֤άϧʔϓͱ‫ڞ‬༗͠ɼΑΓચ࿅͞Εͨ‫ݕ‬ग़‫ث‬ͷ։ൃΛߦ͍ͬͯ͘͜ͱ͕೔ຊάϧʔϓͷ໾ׂͷ 1 ͭͰ͋Δͱࢥ͏ɻ

(2014) 32.

[5] ਿࢁߊ, ࠷ۙͷ TPC, ߴΤωϧΪʔχϡʔε 26 (2007) 225.
[6] David R. Nygren, The Time-Projection Chamber,
http://lss.fnal.gov/conf/C740805/p58.pdf[7] http://magboltz.web.cern.ch/magboltz/[8] RL Gluckstern, NIM A, 24, p.381-389.
[9] S.C. Curran and J.D. Craggs,”Counting tubes, theory
and applications, London: Butterworths”.

[10] F. Sauli, L. Ropelewski and P. Everaerts, NIM A 560(2006) 269.

[11] P. Gros et al.,
”Blocking positive ion backflow using a GEM gate: experiment and simulations”,
DOI:10.1088/1748-0221/8/11/C11023.

[12] K. Ikematsu, DOI: 10.1109/NSSMIC.2014.7431237.
[13] M. Kobayashi et al., NIM A 641 (2011) 37.
[14] R. Yonamine et al.,
DOI: 10.1088/1748-0221/9/03/C03002.

[15] https://particle-physics.desy.de/e252106/e252106/e252211.
[16] http://aliceinfo.cern.ch/Public/en/Chapter2/Chap2 TPC.html.
[17] http://ep-ed-alice-tpc.web.cern.ch/ep-ed-alicetpc/altro chip.htm.

9 ҰൠʹΞϊʔυͰଌఆͰ͖Δ෼͸༗ޮΨεήΠϯͱ‫ݺ‬͹ΕɼGEM݀ͰΨε૿෯͞Εͨશిࢠ‫܈‬ΛઈରΨεήΠϯͱ‫Ϳݺ‬ɻ[18] http://consult.cern.ch/writeup/heed/