The development and performance evaluation of a hybrid photo- - PowerPoint PPT Presentation

The development and performance evaluation of a hybrid photo- detector for Hyper-Kamiokande M. Jiang, Y. Nishimura A , Y. Suda B , Y. Okajima C , R. Akutsu A , D. Fukuda D , S. Hirota, M. Yokoyama B , M. Nakahata A , M. Shiozawa A , Y. Hayato A , S. Nakayama A , H. Tanaka A , T. Nakaya, A. Minamino, A.K. Ichikawa, M. Kuze C , A. Taketa E , Y. Kawai F , T. Ohmura F , M. Suzuki F Kyoto.U, ICRR A , U.Tokyo B , Tokyo Tech C , Okayama.U D , ERI E , HPK F 2015/7/7 Photo Det 2015 @ Moscow 1

Hyper Kamiokande experiment & PD candidate • A proposed next generation underground water Cherenkov detector • 1Mt Water tank (Super K × 25) • 100, 000 PDs (Super K × 9) • Three candidates of 50cm PD • Better energy • Performance is • Simpler resolution known well structure • Better time • Stable • Much better resolution resolution Venetian Blind PMT Box & Line PMT Hybrid Photo-detector (B&L PMT) (Super Kamiokande (Super-K) PMT) (HPD) (Hamamatsu R3600 NQE) (Hamamatsu R12860 HQE) (Hamamatsu R12850 HQE) High performance 2015/7/7 Photo Det 2015 @ Moscow 2

Principle of HPD • Using an Avalanche Diode (AD) instead of dynode to multiply Typical values in an HPD prototype photoelectron Avalanche Diode (AD) • Simpler structure ~300V → Cost reduction • Fast and low fluctuation process of ｅ Amp electron convergence and ΔV Vacuum ~ -300V multiplication Tube AD gain Total gain Bombardment gain → Good timing resolution × ~1600 × ~200 ~10 5 ~8kV × Gain of Amp • High first stage gain → Good 1 p.e. detection capability 2015/7/7 Photo Det 2015 @ Moscow 3

Outline • Introduction • Development status • HPD system • Performance Evaluation of 50cm HPD with 5mm AD • Development of 50cm HPD with 20mm AD • Development status and issues due to large area AD • Some solutions proposed • Multi-ch AD • New preamplifier with decoupling transformer • Summary 2015/7/7 Photo Det 2015 @ Moscow 4

Introduction 2015/7/7 Photo Det 2015 @ Moscow 5

Development of 50cm HPD 50cm High QE HPD (w/ 20mm AD) • Target design. • High noise level due to large AD stray Capacitance • Some solution has been proposed Collection Efficiency ~ 90% C AD ~ 800pF QE: ~30% @ Maximum (~400nm) 50cm High QE HPD (w/ 5mmAD) • Operate properly 20cm HPD (w/ 5mm AD) • Performance has been evaluated • Operate properly Theme of today’s talk • Performance has been Collection Efficiency ~ 40% evaluated fully C AD ~ 60pF • Testing in a 200t tank QE: ~30% @ Maximum(~400nm) • QE: ~22% @ Maximum (~400nm) 2015/7/7 Photo Det 2015 @ Moscow 6

HPD System • Equipped with • a preamplifier • a HV power supply. surge protection Low pass filter to reduce the noise from HV 2015/7/7 Photo Det 2015 @ Moscow 7

Evaluation of 50cm HPD with 5mm ΦAD 2015/7/7 Photo Det 2015 @ Moscow 8

Condition Pulse shape and 1p.e charge response HV:8kV AD Bias V:293V AD:5mm Pulse Shape 1PE Charge Distribution Peak HPD B&L PMT 50 cm HPD w/5mm AD Super-K PMT 50 cm Box&Line PMT (B&L PMT) Valley 50 cm Super-K PMT 50 HPD w/ 5mm AD (w/ preamp) Super-K PMT Rise Time 7.4 10.6 Fall Time 11.5 13.1 Pulse width (FWHM) 17.1 18.5 1pe resolution (σ/μ) 16% 53% Peak / Valley Ratio 4.0 2.2 In the 3 candidates of PDs, HPD (w/ 5mm AD) has • fast response The performance of HPD is mainly determined by preamplifier • the best 1p.e. resolution in charge distribution 2015/7/7 Photo Det 2015 @ Moscow 9

Condition HV:8kV AD Bias V:293V AD:5mm Time resolution After the time walk correction σ FWHM Super-K PMT Super-K PMT Better time resolution for higher luminosity • 1p.e. ： 1.0ns (σ) 3.6ns(FWHM) • High luminosity ：～ 120ps(σ) ~400ps(FWHM) Time resolution of 50cm HPD w/5mm AD is better than that of Super-K PMT (Hamamatsu R3600) and Box & Line PMT 2015/7/7 Photo Det 2015 @ Moscow 10

Condition HV:8kV AD Bias V:293V AD:5mm Linearity • We use two laser diodes to Charge (pC) evaluate the linearity of the It is limited by the maximum output output of preamplifier • We fixed the output luminosity ( ～ 800mV) of A and change the one of B The expected output according to gain calculated from 1 p.e from 1 p.e to several hundred p.e. by to check the linearity of wide region We confirmed the linearity is kept in 6% from 1p.e. to 140 p.e. Output Laser Diode A+B lighting at the same time p.e. The expected output is O(A+B) O(A+B)=O(A)+O(B) Laser Diode B (Variable) O(B) The intrinsic linearity of HPD is better than that Laser Diode A (Fixed) of PMT because it is harder to saturate for AD O(A) than for dynode. A B i A+B i Number of Photon 2015/7/7 Photo Det 2015 @ Moscow 11

Condition HV:8kV AD:5mm Temperature dependency 50 cm HPD (w/preamp) 20 cm HPD (w/preamp) Gain Gain × 10 6 AD Bias V Temperature coefficient @20 ℃ 16 HK Temperature :13 ℃ HK Temperature :13 ℃ Temperature coefficient @20 ℃ 14 -3.1%/ ℃ -2.1%/ ℃ 12 10 339V -2.4%/ ℃ 8 AD Bias 253V 6 -2.2%/ ℃ 300V 280V Temperature ℃ Temperature ℃ • Both of them use an AD with a diameter of 5mm, their temperature coefficient also has a similar value. • The temperature dependency of HPD is stronger for higher Bias voltage. • In Hyper-K, surrounding water temperature is expected be 13 ℃ and stable. 2015/7/7 Photo Det 2015 @ Moscow 12

Development of 50cm HPD with 20mmΦ AD 50cm HPD with 5-ch 20mm AD New preamplifier with decoupling transformer (tested in a 15mm AD) 2015/7/7 Photo Det 2015 @ Moscow 13

Development status of 50cm HPD with large AD • Large photocathode (50cm HPD) Photocathode → Large AD → Large Stray Capacitance → Low S/N • Some solution • Multi-ch AD (Segmented AD) • Avalanche Improvement on Preamp • Diode(AD) Decoupling Transformer • Bootstrap type Preamplifier • Low capacitance AD HV module: • In: 5V~10V • Out: 8kV 2015/7/7 Photo Det 2015 @ Moscow 14

50cm HPD with 5ch 20mmΦ AD 2015/7/7 Photo Det 2015 @ Moscow 15

5ch AD Multi-ch 20mmΦ AD Ch3 Ch2 • A smaller area leads a smaller noise Ch4 Ch1 Ch5 • The area of each channel is same. • For the 5ch AD, the noise level is expected to be the same as √ 5 × 8.9mm AD ~ 44% of 20mm AD 2015/7/7 Photo Det 2015 @ Moscow 16

Condition HV:8.4kV AD Bias V: 415V AD: 5ch 20mm BW: 20MHz 5-ch 20mm AD of HPD • The performance of 5-ch 20mm AD is tested in a 50cm HPD 50ns • For the readout electronics, a sum amp is 5mV used to combine the output signal of each channel 1pe Signal Output of 5ch AD … … Ch3 … filter I-V HV Power Sum amp Signal out Ch2 （ +8kV - V AD ） I-V filter V AD Ch1 （ +8kV ） filter protection 5-ch AD 50V/mA I-V inverted amplifier 2015/7/7 Photo Det 2015 @ Moscow 17

Condition HV:8.4kV AD Bias V: 415V Pulse shape and 1p.e charge response AD:5-ch 20mm Voltage (mV) Entries Pedestal 1pe 2pe 3pe 5.57mV pC Time (ns) -4 0 4 8 12 16 20 24 28 50cm HPD w/ 5ch 20mm AD 50 cm HPD w/ 5mm AD Super-K PMT Rise Time (ns) 11.7 7.4 10.6 Fall Time (ns) 18.9 11.5 13.1 Pulse width (FWHM)(ns) 32.3 17.1 18.5 1pe resolution (σ/μ) 28% 16% 53% Peak / Valley Ratio 3.08 4.0 2.2 HPD (w/ 5ch 20mm AD) has • a slow response (even comparing with Super-K PMT) • better 1 p.e. resolution than the Super-K PMT, but lower than that of 50cm HPD w/ 5mm AD 2015/7/7 Photo Det 2015 @ Moscow 18

New amplifier with decoupling transformer Tested on a 50cm HPD w/ 15mmΦ AD 2015/7/7 Photo Det 2015 @ Moscow 19

New amplifier with decoupling transformer • A usual capacitor coupling for deriving a signal from AD at 8 kV brings a large noise due to a large AD stray capacitance. As a result, another coupling transformer is added to suppress the noise by reducing the capacitance seen by the amplifier. • The prototype circuit of the amplifier with decoupling Circuit w/o trans transformer has been made and tested on HPD NEW! with 15mm AD. Circuit w/ trans In this study, the impedance ratio of the transformer is 1:9 2015/7/7 Photo Det 2015 @ Moscow 20

w/o trans Condition HV:11kV AD Bias V:415V AD:15mm Performance in a 50cm HPD w/ trans BW: 20MHz 5mV Charge Distribution 20ns Pulse Height Distribution w/o trans w/o trans w/ trans w/ trans mV pC -2 0 2 4 6 8 10 -2 -1 0 1 2 3 4 5 6 Distribution noise signal (μ) P/V 1p.e. resolution w/ trans Charge 0.31pC (σ) 1.63pC 4.90 26.9% Pulse Height 0.92mV (μ) 3.54mV 11.31 29.5% w/o trans Charge 0.55pC (σ) 2.62pC 1.38 49.1% Height 0.69mV (μ) 4.47mV 2.59 64.1% Decoupling transformer can improve the performance • Faster response and better 1p.e. resolution 2015/7/7 Photo Det 2015 @ Moscow 21