Status of the Development of MPPC for LXe detector Upgrade Daisuke Kaneko International Seminar on Lepton Flavor Physics with Most Intense DC Muon Beam 0 1 Reminder 1 Application to LXe detector Sensitivity to VUV (λ=175nm) 1 p.e. resolve with 12x12㎟ 0 p.e. Photon Detection Efficiency 25% 3x3 ㎟ (2012-5) 12x12 ㎟ (2012-12) 20% 12x12 ㎟ (2013-2) 15% 10% 5% 0% 0 1 p.e. 1 2 Over Voltage [V] 2 p.e. Long tail (τ～200ns) How to reduce long tail ? Target is about 50ns (～Scintillation decay) Worse S/N Increase pileup etc. International Seminar on Lepton Flavor Physics with Most Intense DC Muon Beam 2 Reminder 2 • Reduce quench resistance as low as possible. • Reduce input resistance of amplifier Tail is not be reduced than expected with lower quench Decay constant [ns] How to reduce long tail of 12×12㎟ MPPC ? 400 300 200 100 0 10 • Divide and connect in series active sensor area 100 1000 10000 Quench resistance [kΩ] Waveform is distorted with long coaxial cable 200ns Most realistic plan The effect was confirmed at room temperature test. Rs = 33Ω, 10m cable International Seminar on Lepton Flavor Physics with Most Intense DC Muon Beam 3 Serial connection of MPPC Reduce sensor capacitance by subdividing 12mm×12mm of active sensor region. palarel：𝐶 = 𝑐 + 𝑐 + 𝑐 + 𝑐 = 4𝑐 serial：𝐶 = 1 1 + 𝑐 𝑐 1 𝑐 + + 1 −1 𝑐 = 𝑐 4 Signal is expected to be sharpened due to smaller capacitance, while there is anxiety that S/N become worse. International Seminar on Lepton Flavor Physics with Most Intense DC Muon Beam Serial connection test at room temp. Set up for room temp. test 4 Observed Waveform MPP C LED light, averaged 4 serial 30ns 2serial,2parallel 50 ns 4parallel 200ns LED mask International Seminar on Lepton Flavor Physics with Most Intense DC Muon Beam 5 Set up for LXe temp. test We tested 2 types of connection Simple serial and Hybrid connection in LXe. Simple serial connection 6mm Hybrid connection Serial – signal Parallel - bias preamp bias ○ Less parts × Extra parts ○ Automatically over voltage is adjusted × Gain uniformity is required × 4 times higher voltage ○ Same voltage as single MPPC × Voltage difference between each sector ○ All sectors have common voltage International Seminar on Lepton Flavor Physics with Most Intense DC Muon Beam 6 Assembly work Every time the xenon chamber needed to be open to modify connection of MPPCs. MPP C LED Yuki Nakai from Kyushu univ. International Seminar on Lepton Flavor Physics with Most Intense DC Muon Beam 7 Waveform of 1 photo electron Hybrid 4segments V→ Flashing LED and trigger with synchronized pulse. Vov = 3.0V Hybrid 2segments Vov = 3.0V Simple • Waveform is as sharp as 3×3㎟ MPPCs • 1 p.e. signal can be resolved 0 p.e. 1 p.e. Vov = 3.0V 2 p.e. Simple 3.0V Parallel Vov =1.5V ×10 amp t→ charge → Baseline RMS have no significant difference, ～2mV International Seminar on Lepton Flavor Physics with Most Intense DC Muon Beam How many segments to divide We tested 4 & 2 segments. 4 segments (C/16) 2 segments (C/4) International Seminar on Lepton Flavor Physics with Most Intense DC Muon Beam 8 9 Gain (multiplication factor) Gain is 4～10×105 2 segments Gain is lower as capacitance is smaller. Amplitude is almost the same. 4 segments Lower than that of parallel connection, but 1 p.e. is still resolved with proper voltage. C = e × Gain / V Hybrid1 : 18.7 ±1.9 [fF] Hybrid2 : 32.9 ±0.4 [fF] International Seminar on Lepton Flavor Physics with Most Intense DC Muon Beam Decay time and Connection type Calculated decay constant by fitting waveform by event. 4 segments 25ns 2 segments 46ns ↕ Parallel 200ns 2 segments 4 segments 50ns of target time constant is achieved in both cases. Estimated time constant (τ = RC) from 1.20MΩ quench resistance and previous capacitance C 4 segments : 22.4ns 2 segments : 39.4ns Consistent to observation within about 20% error. International Seminar on Lepton Flavor Physics with Most Intense DC Muon Beam 10 Leading edge and connection type Leading time constant is also shorter in smaller capacitance. 4 segments 2 segments Leading time constant seems to depend on o.v. , fitting for small waveform was difficult. ↓ To use pico sec pulse laser, Hamamatsu PLP-10 400nm. Available soon. International Seminar on Lepton Flavor Physics with Most Intense DC Muon Beam 11 12 Effect of long cable In MEG LXe detector, long coaxial cable of about 10m exists between sensor and read-out electronics. 2 segments 4 segments Cable Length [m] Gain does not change, while decay time slightly increases (1ns/m). Constant is 56ns at 11m of 2 segments, but still acceptable. International Seminar on Lepton Flavor Physics with Most Intense DC Muon Beam 13 Summary of serial connection Gain (@ 3V) Peak separation Noise rms [mV] Decay const [ns] Rise const [ns] 4 segments 4×105 ○ 2.0 – 2.5 25 ～ 33 2–3 2 segments 8×105 ◎ 2.0 – 2.5 46 ～ 56 4-5 Gain is larger and peak is clearer when number of segment is few. This makes charge calibration easier and relative gain error smaller. On the other hand, signal is sharper with finer segmentation. Timing resolution is expected to be better, and pile-up will be reduced. 4 segments is favorable, because gain error is small enough, and timing resolution should be as good as possible. In addition, if single p.e. can not be resolved, it is easier to switch 2 segments. International Seminar on Lepton Flavor Physics with Most Intense DC Muon Beam Package design (preliminary) International Seminar on Lepton Flavor Physics with Most Intense DC Muon Beam 14 15 PCB based feedthrough Slope (Charge/Voltage) Charges of 1 p.e. event are compared between usual LEMO-connector and PCB feedthroughs. = 100.8 ± 1.2 [fF] LEMO = 103.0 ± 2.0 [fF] MMCX About for charge, there is no difference. Another properties are being analyzed. International Seminar on Lepton Flavor Physics with Most Intense DC Muon Beam Summary and prospects 16 Comment Several types of serial connection were tested Hamamatsu in LXe. ・30 – 50 ns of decay constant was achieved. Low PDE of previous sample ・Single p.e. can be resolved was caused by a unwanted layer on surface, and this layer can be All basic requirements to MPPC were satisfied removed by some process. Hybrid, 4-segment connection is advantageous forsamples main design New arrive soon Next to do Confirm improvement of PDE in new technology MPPC. MC simulation with concrete MPPC parameters. Detailed assembly design of detector and prototype. Preparation of prototype test. International Seminar on Lepton Flavor Physics with Most Intense DC Muon Beam Fin. 現MEGにおける液体キセノン検出器 18 μ+→e + γ 崩壊で発生する 52.8MeVのγ線を検出する。 900ℓの液体キセノン (LXe) PMT Present 入射面に216個 他の面に630個の 有効面積の直径が46mmの 光電子増倍管(PMT) γ-ray PMT に近い位置でγが反応した場合、光 子の収集効率に場所依存性が大きくな る。 ↓ 検出器の浅い位置では分解能が悪い。 International Seminar on Lepton Flavor Physics with Most Intense DC Muon Beam 19 液体キセノン検出器の更新 より小型のセンサーを入射面に 配置してuniformityを良くし て、分解能を向上させる PMT MPPC Upgraded CG image γ γ-ray ←現在 更新後→ 浜松ホトニクス製のピクセル 光検出器(MPPC)を採用する予定 入射面に約4000個の 紫外線に感度があり有感面積 12×12mm2を持つMPPC γ xenon volume acceptance 入射面の幅を広げる → エネルギー漏れが減少 光電面を同平面上に → レスポンスがより均一に International Seminar→ on Lepton Flavor Physics with Most Intense DC Muon Beam 入射前の物質量が減少 検出効率が向上(約10%) 20 シャワーの見え方の違い 現在 更新後 MCによる、同一のγ線パイルアップイベント イメージング能力が格段に向上 International Seminar on Lepton Flavor Physics with Most Intense DC Muon Beam 更新後の性能 depth ≧ 2cm 60 % of events depth ＜ 2cm 40 % of events Upgraded Present 21 エネルギー分解能 σup 2.4% ↓ 1.1% Upgraded Present σup 1.7% ↓ 1.0% 52.8MeV(MEGで探索する信号)に対する応答 International Seminar on Lepton Flavor Physics with Most Intense DC Muon Beam Position resolution in σ [mm] 更新後の性能 位置分解能 Red : Present Blue : Upgraded Depth from inner face [cm] International Seminar on Lepton Flavor Physics with Most Intense DC Muon Beam 22 23 Raw-Waveform 25μ Low Rq 50μ Low Rq 25μ Mid Rq 50μ Mid Rq 25μ High Rq 50μ High Rq International Seminar on Lepton Flavor Physics with Most Intense DC Muon Beam pre amplifier International Seminar on Lepton Flavor Physics with Most Intense DC Muon Beam 24 25 Result : Waveform and Quench-R Fitting waveforms with a doubleexponential function works well. ・The tail time constant do not depend on Rq so much ・25µm pitch MPPC is not so different from 50µm. MPPC Type 50 25 Quench R [kΩ] Over voltage [V] R1 Low 349 R2 Mid 606 R3 High 8867 Over voltage [V] R1 Low 719 R2 Mid 1170 R3 High 21433 1 Rising & 1 Trailing component, τr ,τt Trail time constant τt [ns] 1.0 246 277 2.0 - 1.2 255 288 783 2.5 214 218 538 1.5 276 314 3.0 - Rise time constant τr [ns] 1.0 19.6 19 2.0 - 1.2 21 19.4 16.5 2.5 20.7 20.1 23.5 1.5 24.3 20.7 3.0 - International Seminar on Lepton Flavor Physics with Most Intense DC Muon Beam 26 How to shorten waveform Smaller Rs → Effective, but only in limited situation. ↓Data taken with large-area MPPC at room temperature↓ τt= 192 ns Rs = 50Ω short cable τt= 138 ns Rs = 33Ω short cable Rs = 33Ω long cable Tail is reduced with small Rs, but the waveform is distorted with a long read-out cable because of the impedance mismatch. Smaller Rp → Not effective International Seminar on Lepton Flavor Physics with Most Intense DC Muon Beam Cause of long waveform Waveform can not be shortened only by reducing the quench resistance and cell capacitance. MPPC side 27 AMP side Vb Rp bias voltage protect resistance amplifier quench resistance Rq Cd diode (sensor) Rs … C shunt resistance s stray capacitance Rs,Rp×Cs term is dominant against Rq×Cd term under small Rq condition? International Seminar on Lepton Flavor Physics with Most Intense DC Muon Beam 28 90% 80% 70% Total 60% H window 4 50% H window 3 40% H window 2 30% H window 1 relative charge 80 100% 70 60 50 40 30 20 20% 10 10% 0 0% 269 271 0 273 5 10 15 capacitance [nf] Tail constant 267 20 18 16 14 12 10 8 6 4 2 0 0 5 10 15 capacitance [nf] International Seminar on Lepton Flavor Physics with Most Intense DC Muon Beam 29 Set up for LXe temp. test We tested 2 types of connection Simple serial and Hybrid connection 6mm Simple serial connection Hybrid I (4 sectors) Hybrid II (2 sectors) preamp ○ Less parts × Extra parts ○ Automatically over bias voltage is adjusted × Gain uniformity is required × 4 times higher voltage ○ Same voltage as single MPPC × voltage difference between each sector ○ All sectors have common voltage Actual test was done with 3 MPPCs because 1 sample was broken International Seminar on Lepton Flavor Physics with Most Intense DC Muon Beam 1 p.e. ピークの広がり International Seminar on Lepton Flavor Physics with Most Intense DC Muon Beam 30 31 Detailed PDE calculation of G-type MPPC Voltage In 2013Feb-1 test 130150UM-R2 PDE 1.7 Errors 25% type-I 3x3 ㎟ (12年5月) 12x12 ㎟ (12年12月) 12x12 ㎟ (13年2月) 20% 1.4 Gain 3.1% 1.6% Alpha peak 0.26% 0.21% Correction 3.2% 1.7% Model syst. 14% 22% total 22.2% 15.3% 15% 10% voltage 1.4 1.7 PDE +/- 15.5 2.5 16.9 3.7 5% 0% 0 0.5 1 1.5 2 2.5 3 Over Voltage [V] International Seminar on Lepton Flavor Physics with Most Intense DC Muon Beam
© Copyright 2024 ExpyDoc
