7th International Conference on New Developments In Photodetection

7th International Conference on New Developments In Photodetection Development of a cylindrical tracking detector with multichannel scintillation fibers and PPD readout Yuya Akazawa Tohoku University for the J-PARC E40 collaboration

Contents Motivation for development Requirements Construction of Cylindrical Fiber Tracker Fiber construction PPD Read-out Performance evaluation Response for cosmic ray and proton Linearity Energy resolution Summary 2

Σp scattering experiment Σp scattering experiment @J-PARC, Japan ΣN interaction Measurement of dσ/dω of Σp scattering with high statistics It is difficult to use Σ as a target or a beam lifetime (~10-10s) need to produce Σ in a target ± ± ①Production π + p Σ + K + ②Scattering Σ± + p Σ±' + p' Cylindrical Fiber Tracker(CFT) Trajectory Energy deposit PID BGO calorimeter Kinetic Energy NDIP2014 poster Honda Ryotaro π± beam Liquid H2 target CFT BGO calorimeter p K+ ①Production S± ②Scattering S±' p'

Σp scattering experiment Σp scattering experiment @J-PARC, Japan ΣN interaction Measurement of dσ/dω of Σp scattering with high statistics It is difficult to use Σ as a target or a beam lifetime (~10-10s) need to produce Σ in a target ± ± ①Production π + p Σ + K + ②Scattering Σ± + p Σ±' + p' Cylindrical Fiber Tracker(CFT) Trajectory Energy deposit PID BGO calorimeter Kinetic Energy π Beam Liquid H2 target CFT BGO calorimeter S S' p' K+ n p

Σp scattering experiment Σp scattering experiment @J-PARC, Japan ΣN interaction Measurement of dσ/dω of Σp scattering with high statistics It is difficult to use Σ as a target or a beam lifetime (~10-10s) need to produce Σ in a target ± ± ①Production π + p Σ + K + ②Scattering Σ± + p Σ±' + p' Cylindrical Fiber Tracker(CFT) Trajectory Energy deposit PID BGO calorimeter Kinetic Energy π Beam Liquid H2 target S S' K+ n p' p CFT BGO calorimeter Main topic ~development of CFT~ Measurement of energy deposit by CFT with combination of scintillation fibers & MPPCs

Cylindrical Fiber Tracker (CFT) Requirements Energy resolution 400mm m 300m 35% for 70MeV proton for 1 layer Angular resolution : σθ=0.77deg Surround the target Cylindrical shape Long active region 400mm Energy deposit depends on the Mass Resolve proton and π 2 types of fiber configurations Track finding 3 dimensionally Φ layers ( straight layer ) UV layers ( spiral layer ) Φ layer measure Φ U V layer get z position using Φ

Cylindrical Fiber Tracker (CFT) Requirements Energy resolution 400mm m 300m 35% for 70MeV proton for 1 layer Angular resolution : σθ=0.77deg Surround the target Cylindrical shape Long active region 400mm Energy deposit depends on the Mass Resolve proton and π 2 types of fiber configurations Track finding 3 dimensionally Φ layers ( straight layer ) UV layers ( spiral layer ) Some challenges to overcome for development of CFT Fiber construction Special fiber configuration Many channel operation Φ layer measure Φ U V layer get z position using Φ Photon readout fiber by fiber Prototype

CFT prototype 3layers 2 straight layers + 1 spiral layer 1,100 fibers Read fiber by fiber 400mm Readout frame Reflector ESR Scintillation Fiber Kuraray SCSF-78M Diameter 0.75mm MPPC S10362-11-050P HPK MPPC size : 1 1mm2 te Pixel size : 50 50μm2 a r e op & 400 pixels/mppc ead EASIROC board R Specialized for multi-mppc readout ADC, TDC

Construction of CFT prototype Straight layer 400 mm Fiber fixing frame

Construction of CFT prototype Straight layer U層 400 mm 400 mm Fiber fixing frame Spiral layer

Construction of CFT prototype Straight layer U層 3 layers were combined. Fiber fixing frame Φ1+U+Φ2 Number of fiber : ~1100 channels 400 mm 400 mm 100mm 400mm Spiral layer

Readout ~photon sensor~ Number of fiber : 1100 channel Photon sensor MPPC fiber by fiber 30mm A circuit mounting 32 MPPCs MPPC 1 1mm2 64mm Readout frame Edge of fibers

Readout ~photon sensor~ Readout frame Number of fiber : 1100 channel Photon sensor MPPC fiber by fiber Edge of fibers A circuit mounting 32 MPPCs 30mm attach MPPC 1 1mm2 64mm contact EASIROC board fiber Readout frame spacer (rubber sheet) 0.8mm MPPC ADC, TDC, bias adjustment etc... Ref EASIROC chip : proceedings of NDIP 2011 Omega/IN2P3 EASIROC board : R. Honda PD12

MPPC operation For uniformity of MPPCs Each MPPC's gain was adjusted by changing bias voltage. EASIROC 20mV/bit, 0~4.5V for each channel 1,100 MPPCs were adjusted. pedestal MPPC output 1 photon 2 photon Operation voltage Over Voltage 1.4V ADC [ch]

Measurement of cosmic ray Uniformity for all fibers p.e. count Distribution of p.e. for cosmic ray Photon Num of typical fiber p.e. Mean value = 19 p.e. sufficient to distinguish hit Fiber No. Light yield was almost uniform.

Performance evaluation Measurement of energy deposit Linearity Between energy deposit and light yield Energy resolution Require σ/mean = 35% for 70MeV proton for 1 layer in order to resolve proton and pion with 4σ K π± beam p S± n S' ± p' + p± MIP particle Σ decay product cosmic ray

Performance evaluation for proton Test experiment in CYRIC pp scattering experiment 80MeV proton beam from cyclotron @CYRIC in Tohoku Univ. σe(bgo) =1.2% for 80MeV p beam CFT CH2target p beam θ

Performance evaluation for proton Test experiment in CYRIC pp scattering experiment 80MeV proton beam from cyclotron @CYRIC in Tohoku Univ. kinetic energy:e σe(bgo) =1.2% Kinetic energy E [MeV] Ep is selected by θ energy deposit:de Scattering angle : θ response for proton 20~70 MeV CFT CH2target p beam Scattering angle θ [degree] θ for 80MeV p beam

Linearity of light yield Experimental data p.e. compare Simulation Estimated energy deposit

Linearity of light yield Experimental data p.e. compare Simulation Estimated energy deposit detected p.e. For each layer Response function Preliminary Nout = Neff*{1- exp(-b*de/neff)} Neff = effective pixel number of MPPC = 197 cosmic ray Estimated energy deposit [MeV] pixels MPPC covering area to fiber 1mm : 400pixel*(covering ratio) 0.75mm 180pixel

Linearity of light yield Experimental data p.e. compare Simulation Estimated energy deposit detected p.e. For each layer Response function Preliminary Nout = Neff*{1- exp(-b*de/neff)} Neff = effective pixel number of MPPC = 197 cosmic ray pixels MPPC covering area to fiber 1mm : 400pixel*(covering ratio) 0.75mm 180pixel Estimated energy deposit [MeV] How much does non-linearity affect to energy resolution?

Energy resolution Energy resolution [%] Energy resolution of one layer Data Simulation Preliminary Simulation Cylinder Shape of fiber Fluctuation of Photon number MPPC Saturation suggests that resolution will become worse at high de region. Estimated energy deposit [MeV] Resolution was worse than simulation. <-- to be calibrated for each channel Energy resolution of CFT = 28% for 70MeV proton (de = 0.7MeV) satisfied our requirement (35% for 70MeV)

summary We plan to perform Σp scattering experiment at J-PARC CFT(Cylindrical Fiber Tracker) will measure the trajectory and the energy deposit Construction a Prototype consists of 3 layers Scintillation Fiber + MPPC 2 straight layers +1 spiral layer 1,100 fibers MPPCs which read each fiber were operated by EASIROC board Performance evaluation Measured cosmic ray and pp scattering Cosmic-ray Mean detected photon number = 19 p.e. Linearity MPPC saturated in high energy deposit region. Effective pixel number of MPPC = 197pixels consistent with fiber covering area Energy resolution worse than that of simulation to be improved σ/mean = 28% for 70MeV proton(de=4.7mev) satisfied our requirement

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Calibration method Response function Layer by layer (now) detected p.e. To improve the energy resolution contain the effect of the deviation of MPPC' gain fiber by fiber Energy resolution should be improved. cosmic ray Estimated energy deposit [MeV] Expand MPPC effective area Inserting a spacer between fiber and MPPC MPPC saturation will become weaker. 0.75mm MPPC fiber 1mm fiber etc... Spacer MPPC

A design of actual type Actual detectors The design have almost finished Just now constructing CFT BGO CFT+BGO CFT BGO calorimeter 4 Φ layers,4 U V layers 24 BGO(30 25 400mm3) ~5,000 fibers will be placed cylindrically 32

Efficiency actual hit? Efficiency for Φ layer (actual hit) / (expected by other 3 hit track) expected by other 3 hit y[mm] Φ=0 Φ2-① Φ1-① Φ1-③ Φ2-③ Φ Φ1 U Φ2 { x[mm] Number of photon is sufficient Position dependence efficiency = 87% Φ suggest that there were some space between some fibers to be improved

Linearity of light yield energy deposit [MeV] Linearity between energy deposit(simulation) and p.e.(actually detected) Estimated de for pp scat. Detected p.e. detected p.e. Compare via scattering angle h cosmic ray energy deposit [MeV]

angular resolution Trajectory was reconstructed by CFT ----> vertex ( beam line trajectory) vertex Target peak 13.7mm(σ) proton beam Vertex (beam line) [mm] estimated from σvertex=13.7mm σδθ=1.0 Ideal resolution (Geant4) σδθ=0.77, σvertex=9.4mm Prototype nearly realized the simulated performance to be better by improving position precision Ep'measure(BGO+CFT) [MeV] CH2target(200μm t) Angular distribution of Ep' Ep'calc (pc scattering) Ep'calc (pp) Scattering angle [degree]