Photosensors and Front-end Electronics for the Hyper … · 2018. 7. 31. · Photosensors and...

Photosensors and Front-end Electronics for

the Hyper-Kamiokande ExperimentMarcin Ziembicki

for the Hyper-Kamiokande Proto-Collaboration

10th International Workshop on Ring Imaging Cherenkov DetectorsRussian Academy of Sciences

July 29 – Aug 4, 2018, Moscow, Russia

260 kton

Hyper-Kamiokande PhotosensorsHyper-Kamiokande (HK)

40%photo-

coverage

New high-QE 20” Box&Line PMT

High detection efficiency, very good time & charge resolutions

Pressure tolerance for min. 60 m depth

8” PMTs or 3” PMTsPotentially WLS (under study)

(190 ktonFiducial

Mass)for 1 tank

×2 tanks

60 m

⚫ Rich physics programs ν oscillations

▶Leptonic CP violation, ν mass hierarchy, …

Nucleon decay discovery

ν astrophysics▶Supernova burst ν, …

→ Wide dynamic range

→ High rate tolerance→ Clear photon counting,

→ ns time resolution,

→ Good time&charge resolutions,high detection efficiency, ..

low background

Requirements

Multi-PMT modules (3” PMTs)Smaller PMTs → better timing responseAdditional directional informationMain building block of intermediate detector (E61)

Inn

er

De

tect

or

(40

00

0 s

en

sors

)

Outer Detector (6700 sensors)

2

Hyper-K 20” Photodetector System

• Event Trigger▪ Sum of hits can be used to make events.

▪ Dark rate has a significant impact on the lowest energy, in both trigger and reconstruction ➢ Registering low energy events requires lowering dark rate and increasing

detection efficiency

• Recording both hit time and charge. ▪ Time walk can be corrected using charge.

All channels are triggered independentlyby setting a threshold below single photoelectron level.

Slowflow

deep

water

Vacuum ImplodedBulb is pressurized.

Cover is pressurized.

Usual case Implosion

Slow water flow through cover holessuppresses the shockwave.

Shockwave prevention cover Electronics in the tank

… ~24 photo-sensors

To avoid chain reaction of implosion

3

Improved Dynode Structure / HV Supply SchemeBox&Line PMT

+2kV, 107gain

Box & Line

New

Efficient collectionUniform drift path→ High charge&time resolutions

+High QE

BoxLin

e

Hamamatsu R12860

A mesh to make flat electric potential on surface has 95% aperture.

Effective gain(δ)δ１= 18.6

δ1 = （Bombardment gain on Dy1)×(CE of secondary electron from 1st to 2nd dynode）

→ Improvemed 1PE charge resolution (down to 35%)

• Positive HV is necessary to minimize dark rate.

• Parameters optimized for• Less ringing• Wide dynamic range• Constant collection efficiency

• Tuning finished.

Max. +2600VTotal Resistance 5.9 MΩTypical Divider Current 339 μA at +2000V

Ratio 13 : 1 : 3.5 : 4 : 2 : 2 : 1 : 1 : 1 : 1.5 : 1.5 : 1.2

4

Performance

Time ChargeBox&Line PMTSK PMT

Box&Line PMTSK PMT

50% → 35% σ2.1ns → 1.1ns σ7.3ns → 4.1ns FWHM

at Single PE

94 I I.2 HYPER-KAMIOKANDE DETECTOR

Super-K PMT within the 46 cm area, the HQE B&L PMT reaches 95% in the same area and st ill

keeps a high efficiency of 87% even in the full 50 cm area. This high CE was achieved by opt imizing

the glass curvature and the focusing elect rode, as well as the use of a box-and-line dynode. In the

Super-K Venet ian blind dynode, the photoelect ron somet imes misses the first dynode while the

wide first box dynode of the box-and-line accepts almost all the photoelect rons. This also helps

improving the single photoelect ron (PE) charge resolut ion, which then improves the hit select ion

efficiency at a single PE level. By a measurement at the single PE level, we confirmed the CE

improvement by a factor of 1.4 compared with the Super-K PMT, and 1.9 in the total efficiency

including HQE. Figure 58 shows that the CE response is quite uniform over the whole PMT surface

in spite of the asymmetric dynode st ructure.

A relat ive CE loss in case of a 100 mG residual Earth magnet ic field is at most 2% in the worst

direct ion, or negligible when the PMT is aligned to avoid this direct ion on the tank wall. The

reduct ion of geomagnet ism up to 100 mG can be achieved by act ive shielding by coils.

Position angle [degree]-90 -80 -70 -60 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90R

ela

tive s

ingle

ph

oto

ele

ctr

on h

it e

ffic

iency

0

1

2

R12860-R3600_カウントグラフ（Y軸）

17

各ポジションでのカウントをグラフ化（標準球のカウントを同じにした場合）

このデータのカウント値は入射光子数が一定になる様補正してあるが、QEとCEの固体差が含まれている。R12860とR3600では、同一光子数を入射したと仮定した場合のカウント値に歴然と差があることが分かる。 FIG. 58. Relat ive single photoelect ron detect ion efficiency as a funct ion of the posit ion in the photocathode,

where a posit ion angle is zero at the PMT center and ± 90◦ at the edges. The dashed line is the scan along

the symmetric line of the box-and-line dynode whereas the solid line is along the perpendicular direct ion of

the symmetric line. The detect ion efficiency represents QE, CE and cut efficiency of the single photoelect ron

at 0.25 PE. A HQE B&L PMT with a 31% QE sample shows a high detect ion efficiency by a factor of two

compared with normal QE Super-K PMTs (QE = 22%, based on an average of four samples).

Total Detection Efficiency of 1peQuantum Efficiency (QE)

high-QEs (HQE)

SK → 30% at peak22%

×2

(~35% in recent products)

Box&Line PMTSK PMT

Confirmed sufficient performance for Hyper-K

5

Y. Nishimura, et. al..

Dark Rate

• Still trying to reduce dark rate by optimizing design/production.

By temperature

(HV at 107 gain)

Hyper-K water temp.

SuperK PMT

Old type

By bias voltage

(Rate at 1/4 PE threshold)5 Box&Line PMTs

(Old type in 2015)

1 Super-K PMT

5 samples

Stabilization in days

Dar

k ra

te (

at 1

.5m

V)

[kH

z]

7.6 kHz avg.at 1.5 mV thre.

Dependency by Schottky effect, CE is almost constant.

By time

North

Dark room w/ cooling

at 15deg.

ICRR, Univ. of Tokyo, Japan

Measuring many ~20 PMTs for a long time to confirm stabilized performance.

10]´ Threshold [mV0 10 20 30 40 50 60 70

Da

rk R

ate

[kH

z]

2

4

6

8

10EA0225

EA0241

EA0248

EA0250

EA0270

0 2 4 6 8 10 12 14[mV]

(HV at 107 gain)

By hit threshold

5 Box&Line PMTs

Dar

k R

ate

[kH

z]

6


2103

10Expcted Charge [PE]

210

310

Me

asure

d C

ha

rge

[P

E]

Rate Tolerance and Linearity

for supernova burst detection(10MHz at max in low PE)

Sufficient high rate tolerance

Pulse frequency [kHz]

2103

10

Mea

su

red C

ha

rge [

au

]

0

0.2

0.4

0.6

0.8

1

1.2

25 PEs

50 PEs

100 PEs

Within 5% up to 170 μA

→ 78 MHz at single PE

Rate Tolerance of Gain 25 PE

50 PE

100 PE

Baseline shift

High current

Voltage shift due to a coupling capacitor

All deficiencies of positive bias can be solved in electronics, while lower dark rate provided by positive HV is essential for HK physics.

The shift is subtracted

Good linearity over 1000 photoelectrons

Expected Charge [PE]

Linearity

7


Other 50-cm Photodetector Candidates• HPD (Hybrid Photo-Detector)

• MCP PMT• Originally for JUNO

• Using micro channel plate

• Confirmed comparable performance with the Box&Line PMT.

Time [ns]-10 0 10 20

SK 7.3 ns

Box&Line 4.1 ns

HPD 3.6 ns(w/ TQ correction 3.2 ns)

PhotoelectronsCharge [photoelectron]-1 0 1 2 3

Entr

ies (

a.u

.)

HPD 15%Box&Line 35%Super-K 53%[σ / peak]

(--- 1/2ch AD)

FWHMSingle PE transit time spreadSingle PE peak

1 20” HPD was installedin 200-ton water tank.

Highest 1PE resolutions

Box&Line PMT

SK PMT

Time [nsec]

Even

ts

+ MCP PMT orig. for JUNO /

for Hyper-K after improvement

spot light at center

+8kV, 105gain

AD ×1600

×100+ preamp

20mmΦ

high QE

Electrode added for HK

Significantly improved TTS

8


Covers⚫ Accidental implosion of bulb

in water might cause a chain implosion by a shock pulse. A shockwave prevention cover

made of FRP was developed for Super-K for 40m depth.

⚫ New covers were developed for a deep Hyper-K tank up to 60 m with clean materials.

Slowflow

deep

water

Vacuum ImplodedBulb is pressurized.

Cover is pressurized.

Usual case Implosion

3RD HYDROSTATIC TEST RESULT (V2.2)

•Removed stiffening ring to see if bottom would colapse again in

spite of the repaired section

•This time, no visible damage happened up until 7 bar, where the

test was stopped to verify no deformation had indeed occurred.

•Just in time for delivery to Hokkaido implosion tests

Super-K coverfor 40 m water depth Hyper-K Cover

Stainless steel (3 mm)

13mm acrylic15 mm acrylic

FRP(fiber reinforced plastic)

22kg

Slow water flow through cover holessuppresses the shockwave.

17kg

13 mmacrylic

Stainless steel(2.5 mm)

30kg6.4kg

Weight w/o acrylic (~6kg)

1. Improved cover 3. Stainless steel tube cover2. Resin coverPPS (Poly Phenylene Sulfide)with carbon fiber

Cheap and simple, Developed in Spain

New 3 covers were also tested with bulb implosion inside in 2018.

Cover pressurizedtest in water→ 1 MPa 0.5-0.57 MPa 0.7 MPa

Light weight,fast and easy mass production

Stainless steel

FRONT VIEW SIDE VIEW

Unit : mm

(Pitch Circle Diameter) UV transparent acrylic cover

Photomultiplier tube

Stainless steel cover

Cable hole

Reinforcing ring

Improved covers for light weight or low costBaseline design established by tests

Cover pressurizedtest in water→ 1.2-1.5 MPa

High pressure

water vessel

Cover pressurizedin vessel

9


Implosion Tests

1. Improved cover(Stainless steel) →Success at 80 m three times

Shock wavemonitor

(70 cm front)

Pre

ssu

re[M

Pa]

1. Improved SUS cover(1st test) at 80m

2. Resin cover at 40m3. Stainless steel tube cover at 60m

→ 1/100 suppression

3. Stainless steel tube cover

2. Resin cover

Success at 40 m (1 test only), but failed at 60 m

Success at 60 m (1 test only)

Next: To be reinforced with optimizing design and injection material.

Next: Reduce weight, reach easy mass production/assembly design

~ 6 MPa peakshock wave

Pre

ssu

re[M

Pa]

in 60m water

w/o cover, only 1 PMT at center

Test in 2018 for improved covers

Test in 2016 for baseline design

(Success as well in 80m depth)

Pre

ssu

re[M

Pa]

1/100 suppressionwithout any damage for cover and neighboring PMTs

→Established as HK cover

→ Established10


Multi-PMT for Hyper-K and E61• Adaptation of concept originally invented

by KM3NET

• Instead of using one large PMT (i.e. 20”), use multiple small PMTs (3” to 3.5”)• Small PMTs are cheap – medical industry uses

a lot of them

• Better timing properties

• Better pressure rating (due to external case)

• Directionality of sensor – potentially better reconstruction near walls

• Larger number of channels, more expensiveand power-hungry electronics

• Currently working on mPMT design, characterization of 3” PMTs and designing electronics (both digitization and HV)

11

mPMT Design• Modular – view to mass

production• Aluminium outer structure• Inner support frame / heat

transfer• Optional scintillator disc• 3” PMT sub-assemblies +

support• Acrylic dome• Motherboard + daughter

boards

Acrylic Transparency Tests

Pressure Tests (Acrylic Dome)

Crashed at 85 bar!

12200 300 400 500 600 700 800 (nm)

120

100

80

60

40

20

0

T (%

)

time (s)

0 500 1000 1500 2000

P (

bar

) 60

100

80

40

20

0

M. Scott, A. Ruggeri, et. al.

3” PMT Characterization• Multiple institutions involved• All test sites use pulsed light

source and high speed waveform digitizers

• For dark rate tests, PMTs are stored in dark for min. 48h prior to test; temperature is either controlled or at least measured.

• Recently improved setups to allow for detailed surface scans

Old setup

New setup with XYZ stage and pan & tilt

HamamatsuR14374

HZC XP82B20

ET Enterprise D793KFL

3” 3.5”

3”

13

3” PMT – Gain and TTSTTS, Hamamatsu R14347, S/N BC0032, -HV

PMT TT TTS (FWHM) Gain (x106) Q Resolution

BC0032, -1159V 40.97 ns 1.34 ns 5.19 +/- 0.07 0.36

BC0036, +1113V 45.88 ns 1.52 ns 5.12 +/- 0.04 0.37Ham

amat

su

R1

43

47

PMT TT TTS (FWHM) Gain (x106) Q Resolution

80148, -1324V 49.68 ns 3.62 ns 4.88 +/- 0.04 0.33

80149, +1229V 51.26 ns 3.75 ns 5.16 +/- 0.05 0.35

HZC

X

P8

2B

20

TTS, HZC XP82B20, S/N 80148, -HV

14

A. Fiorentini

3” – Dark Rate

R14374, S/N BC0032 (-HV) R14374, S/N BC0036 (+HV)

XP82B20, S/N 80148, -HV

XP82B20, S/N 80149, +HV

Concept of p.e. efficiency:Ratio of pulses with charge over threshold to total amount of events

Pedestal

> thr

Clearly observable benefit of using positive HV. Currently testing methods of reducing dark rate at negative HV.

15

A. Fiorentini

R14347 – Waveforms

Normalized templates Rise Time & FWHM

Rise Time

FWHM

Normalized Amplitude Spectrum

MHz

• Small (but visible) dependence of waveform shape on PMT orientation wrt. Earth magnetic field

• Relatively large dependence of waveform shape on position of the light source on the photocathode

• trise (1.9 ns, 3.0 ns), FWHM (3.0 ns, 4.7 ns); both increase with PE level (expected)

16

BW 350 MHz

Electronics

• Self-triggering systemo Digitize all photo-sensor signals above discriminator thresholdo Send hit information to readout computerso Use software trigger for event selection & send them to offline system for

storage

• Accurate clock synchronization and GPS

• Stable power supplies (photo-sensors, other systems)

• Front-end boards must provide high reliability o Non-serviceable after filling detector with water

• Low power

Synchronization & GPS

17

Waterproof Cable and Connector

• Dedicated connector was developed.

• Connected to electronics casein water, and can be disconnected.

• Test in high pressure water is planed this summer.

Updates

Connector for PMT ( much smaller than the previous one for HPD )

TNC coaxial signal (RG58C/U) + HV pins

RG58C/U

By Hamamatsu

~20m for Hyper-K

A. Signal

B. +HV

Two coaxial cables for HKCoaxial cable with1-wire HV for SK

9.4 mmφ, 86 g/m

PE sheath

8.4 mmφ, 68 g/m

Improved noise shield and less failure of connection compared with SK.

Updates

Connector for PMT ( much smaller than the previous one for HPD )

18

（9（cable preparation, PMT side

(Hand stripping)1. On the PMT side, 8 cm of outer sheath need to be stripped in order to have a

longer HV cable

2. The （（（（ cable is shorten to 4cm

1. Using the other stripper, place the RG58 at the blue mark by sliding in

in the stripper from the left

2. Start from position 3 to 1 to strip each sheath of the cable. Rotate the

stripper 10 times at each position

3. The HV wire is prepare like for the electronic side

4. by stripping off （（mm of cover sheath.

5. Ensure that male BNC connector is

used for this cable

The procedure is done also on the electronic side with female type BNC cable.

（ red point

mark

should be

aligned for

the blade

and red

button

pushed

forward to

put blade in

position

（ red point marks at 90 deg when cutting along the cable.

（ . Place the tool at （（（ from the end of cable and strip

outer sheath by rotating the stripper 360 deg

（（Rotate the blade 90 deg and slide the tool along the cable

to cut. Remove plastic cover sheath.

18

Digitization Options

QTC + TDCWaveform sampling

Signal from PMT

Time & Charge

Discriminate to get a trigger.Start the output pulse

Integrate the pulse.

Start discharging. Stop the output pulse once

discharged.

Use TDC to record beginning and end of the

square pulse.

Sample the pulse.

Use digital signal processing for triggering

and estimation of time of arrival & pulse charge.

Digitally filter the pulse.

Shape the pulse.

Optional

Optional

IN

INT

OUT

Baseline solution for

20” PMT

Discriminate

Use TDC to get timing

Shape

Use peak sensing ADC to get charge

19

Digitization must not deteriorate performance provided by the photosensor!

QTC + TDC

0 10 20 30 40 50 60 70 80 90

300

400

450

350

500

550

QTC

Ou

tpu

t W

idth

[n

s]

Works well!

QTC Output Width vs Input Charge – First Range

• Both QTC and TDC work well• TDC performance:

▪ DNL: 50 ps to 60 ps ()▪ INL: 60 ps to 70 ps ()

• Charge linearity (QTC + TDC):▪ +/- 1% up to 2000 p.e.

when using low-gain, mid-gain and high-gain channels

20

(Y. Kataoka)

Studies for Waveform ProcessingOptimal Zero-Average FIR Filter

• Tested four methods of time estimation:– Digital Constant Fraction Discriminator

– Optimal Zero-Average FIR Filter

– Matched Filter + Cross-correlation

– Fits (off-line processing only)

• Charge resolution is not a problem

• Easy to achieve sub-sample timing accuracy with sufficient SNR

Source Waveform

ADC SNR = 6.02N + 1.76 [dB]

Good match between model and data

21

Summary• Large, international R&D program

• Extensive study done on 20” photosensors and coverso Current baseline photosensor is

20” Box & Line PMT from Hamamatsu; still trying to lower dark rate

o On-going installation of 150 new B&L PMTs in Super-Kamiokande, incl. prototypes of new covers

o Still optimizing covers

• On-going study for multi-PMT moduleso Characterization of 3” PMTso R&D related to materials and manufacturing o Electronics

• Continuous work on electronicso First prototypes of QTC+TDC approach already

testes and working OKo Sample & hold approach also after first testso FADC prototypes foreseen for end of this year /

beginning of 2019.

22

BACKUP

23

Response Uniformity (20”)

⚫

HV [V]1200 1400 1600 1800 2000 2200 2400

Ga

in

0

10

20

30

40

50

606

10´

2.2 pC

ZB8208

ZB8210

ZB8243

ZB8246

ZB8248

ZB8260

Rise time

(10%-90%)

Fall time

(10%-90%)

Pulse width

(FWHM)

R3600 10.6 ns 13.2 ns 18.8 ns

20” High QE Box &

Line PMT (Bleeder A) 6.2 ns 6.3 ns 10.0 ns

20” High QE Box &

Line PMT (Bleeder B) 6.8 ns 15.2ns 13.2 ns

Owning to the development of new bleeder circuit, ringing

effect of new Box&Line PMT is small. (Bleeder B)

Bleeder B was used for this performance evaluation.

δ : Amplification rate of photoelectron

a : Constant

N : Constant

E : High voltage

Six of Box&Line PMT was measured. All Box& Line PM Ts

are consistent with a numerical formula, δ = a × EN.

Pulse shape

R3600

Time [ns]-50 0 50 100 150

Pu

lse

heig

ht (N

orm

aliz

ed

)

-1

-0.8

-0.6

-0.4

-0.2

0

R3600

Box and Line PMT (Old Bleeder circuit)

Box and Line PMT (New Bleeder circuit)

Time [ns]-50 0 50 100 150

Pu

lse

he

igh

t (N

orm

aliz

ed

)

-1

-0.8

-0.6

-0.4

-0.2

0

R3600



B&L PMT(bleeder A)

B&L PMT(bleeder B)

B&L PMTs serial

Gain curve

1p.e. resolution Box& Line PM T is more improved

than R3600 in photoelectron and

time resolution.

Peak

Valley

1)p.e)resolu0on

Charge

1p.e. distribution

Charge [photoelectron]-1 0 1 2 3

En

trie

s (

a.u

.)

0

0.2

0.4

0.6

0.8

1

1.2

1.4

R3600

High QE Box & Line PMT

Time (ns)-20 -15 -10 -5 0 5 10 15 20 25

Entr

ies (

a.u

.)

0

0.2

0.4

0.6

0.8

1

R3600


1p.e. resolution Time resolution

Time [ns]-50 0 50 100 150

Pu

lse

he

igh

t (N

orm

alize

d)

-1

-0.8

-0.6

-0.4

-0.2

0

R3600



Time [ns]-50 0 50 100 150

Pu

lse

he

igh

t (N

orm

alize

d)

-1

-0.8

-0.6

-0.4

-0.2

0

R3600



R3600

B&L PMT

R3600

B&L PMT

1p.e. resolution

σ/peak

Peak/

Valley

Timing Resolution

σ FWHM

R3600 53% 2.2 2.1 ns 7.3 ns

B&L PMT 35% 4.3 1.1 ns 4.1 ns

Based on the R3600 setting at Super-Kamiokande, HV of each PMT is set to the

value whose 1 p.e. gain is 2.2 pC.

50cm Box & L ine PM T (Hamamatsu R12860)

•

-

-

•

•

Next generation water Cherenkov detector ! Volume : 0.99Mt (Super-K × 25 in fiducial volume)

! Inner detector photo sensors : 99,000(Super-K:11,129)

! Outer detector photo sensors : 25,000(Super-K:1,885)

! Photo coverage : 20%(Super-K:40%)

50 cm photomultiplier tube with box-and-line dynode

• Good photon collection by box shape 1st dynode

• Fast time response by line shape dynode

2015/1/29 4

e（ 1st

1stdynode

might miss1st dynode.

e

Drift path is almost identical.

Drift path can be varied.

Large coverage

(Super-K) (New for 50cm)

Box

line

Enlarging is easy.

+ high QE




2015/1/29 4

e（ 1st

1stdynode


e



Large coverage


Box

line

Enlarging is easy.

+ high QE




2015/1/29 4

e（ 1st

1stdynode


e



Large coverage


Box

line

Enlarging is easy.

+ high QE

Super-K PMT(QE~22%) Box&Line PMT(QE~30%)

R3600 R12860

• Better timing resolution

• Better photoelectron resolution

• High rate tolerance

• Quick gain recovery

• Low noise

• High magnetic field tolerance

Required performance of photo sensors (Box&Line PMT). Need to check the performance

etc…

43cm (17-inch) Box&Line PMT is currently used for KamLand experiment.

! The new Box&Line PMT for Hyper-Kamiokande was developed

to reach 50cm φ effective area and high quantum efficiency.

Recovery

2015/1/29 23

• For that events might happen quickly but not keeping so long time such as stopping cosmic muon decay, the performance of recovery is more important

• We used two continuous pulse to measure the gain recovery.

• Observed change of delay pulse charge= (Delay w/ primary) / (Only delay pulse)

Delay

Primary

Two LDs (140p.e for each)

w/ varied delay

Measured by Akutsu-san

No significant change was observed so far, within 0.5%,which is the same level as measurement error

Gain recovery A quick gain recovery is important to

identify a delayed event in Hyper-K,

such as decay electron from µ.

There were no significant changes observed, and gain is

stable within 0.5% (The gain is statistical fluctuation).

frequency [kHz]500 1000 1500 2000 2500 3000 3500 4000

Att

en

ua

tio

n R

ate

0

0.2

0.4

0.6

0.8

1

1.2

25 p.e.

50 p.e.

100 p.e.

Recovery

2015/1/29 23




Delay

Primary


w/ varied delay



Rate tolerance is necessary for Supernova measurement and so on. ! Supernova of Betelgeuse will bring 10 MHz neutrino interaction at maximum

Gain kept stable, up to 170 µA.

For 1 p.e. signal, the rate can be up to 80 MHz by corresponding above current. (50p.e. can be up to 1.6MHz)

• Most of supernova neutrinos less than 10MHz at maximum bring low energy neutrinos, that is 1 p.e. level for PMT hits.

! Enough tolerance to measure supernova with constant gain.

Am0 100 200 300 400 500 600 700 800

Atte

nu

atio

n R

ate

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

125 p.e.

50 p.e.

100 p.e.

Rate tolerance (pulse frequency) Rate tolerance (charge current)

Gain recovery

Wavelength (nm)300 350 400 450 500 550 600 650 700

Qu

an

tum

effic

ien

cy (

%)

0

5

10

15

20

25

30

35

40

High-QE Box&Line PMT

High-QE Super-K PMT

Normal-QE Super-K PMT

Quantum Efficiency vs. Wavelength

75

50

25

0

-25

-50

-75

Y

X Z

Y

-X

+X

75°

-75°

-75°

75°0°

measurement

point

Angle(deg.) -80 -60 -40 -20 0 20 40 60 80

Re

lative

CE

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

1.1

Magnetic field is X-axis direction

0mG

+100mG

-100mG

Scan for the X direction

Angle(deg.) -80 -60 -40 -20 0 20 40 60 80

Re

lative

CE

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

1.1


0mG

+100mG

-100mG

Scan for the Y direction

Angle(deg.) -80 -60 -40 -20 0 20 40 60 80

Re

lative

CE

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

1.1

Magnetic field is Y-axis direction

0mG

+100mG

-100mG


Angle(deg.) -80 -60 -40 -20 0 20 40 60 80

Re

lative

CE

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

1.1


0mG

+100mG

-100mG


Angle(deg.) -80 -60 -40 -20 0 20 40 60 80

Re

lative

CE

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

1.1


0mG

+100mG

-100mG


Angle(deg.) -80 -60 -40 -20 0 20 40 60 80

Re

lative

CE

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

1.1


0mG

+100mG

-100mG


Angle(deg.) -80 -60 -40 -20 0 20 40 60 80

Re

lative

CE

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

1.1


0mG

+100mG

-100mG


Angle(deg.) -80 -60 -40 -20 0 20 40 60 80

Re

lative

CE

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

1.1


0mG

+100mG

-100mG


Angle(deg.) -80 -60 -40 -20 0 20 40 60 80

T(n

s)

-4

-3

-2

-1

0

1


0mG

+100mG

-100mG


Angle(deg.) -80 -60 -40 -20 0 20 40 60 80

T(n

s)

-4

-3

-2

-1

0

1


0mG

+100mG

-100mG


Angle(deg.) -80 -60 -40 -20 0 20 40 60 80

T(n

s)

-4

-3

-2

-1

0

1


0mG

+100mG

-100mG


Angle(deg.) -80 -60 -40 -20 0 20 40 60 80

T(n

s)

-4

-3

-2

-1

0

1


0mG

+100mG

-100mG


Angle(deg.) -80 -60 -40 -20 0 20 40 60 80

T(n

s)

-4

-3

-2

-1

0

1


0mG

+100mG

-100mG


Angle(deg.) -80 -60 -40 -20 0 20 40 60 80

T(n

s)

-4

-3

-2

-1

0

1


0mG

+100mG

-100mG


Angle(deg.) -80 -60 -40 -20 0 20 40 60 80

T(n

s)

-4

-3

-2

-1

0

1


0mG

+100mG

-100mG


Angle(deg.) -80 -60 -40 -20 0 20 40 60 80

T(n

s)

-4

-3

-2

-1

0

1


0mG

+100mG

-100mG


Difference of signal detection timing Difference of relative Collection Efficiency

! Measurement direction are dynode symmetry direction (X-axis)

and asymmetry direction (Y-axis).

! Measurement point is 0, 25, 50, 75 degree.

! Threshold is 0.25p.e. of 0 mG and 0 degree.

Position dependence

H yper-K amiokande project

! One candidate of photo-sensor is 50cm Box& L ine PM T

Detailed performance evaluation of New 50 cm Photodetectors for Hyper-Kamiokande

Search for Neutrino oscillations, mass hierarchy, nucleon decay, super-nova relic neutrinos. Kajita-san & Arthur B. McDonald got 2015 Novel prize!

Reference – arXiv :1109.3262v1: Letter of Intent : The Hyper-Kamiokande Experiment Detector Design and Physics Potential

Dark rate

Threshold [mV]0 2 4 6 8 10

Da

rk R

ate

[kH

z]

1

10

210

Date06/11 06/18 06/25 07/02

Da

rk R

ate

[kH

z]

9

9.5

10

10.5

11

11.5HV on

After pulse

ns0 10000 20000 30000 40000

Exp

ecte

d n

um

ber

of

aft

erp

uls

es/m

ain

pu

lse

*50

0ns

-0.005

0

0.005

0.01

0.015

0.02Model number

ZB8210

EA0037

EA0045

EA0046

EA0046

EA0052

EA0053

Efficiency

Pulse shape

Gain

L inearity

Expected Charge [p.e.]0 100 200 300 400 500 600 700 800

Me

asure

d C

ha

rge [

p.e

.]

0

100

200

300

400

500

600

700

800

Rate tolerance

R3600(Super-K PMT)

(Normal photocathode)

Box&Line PMT

(High QE photocathode)

Quantum efficiency ~22% ~30%

Collection efficiency 67% (61%) 95% (85%)

Sensor Efficiency (QE × CE) ~15%(~13%) ~29% (~26%)

The linearity is kept up to 340 p.e. within gain drop less

than 5% .

The signal of large number of photoelectron ( > 340 p.e.) is

revised by the result.

: φ 460 mm (φ 498 mm)

Dark noise affects an accuracy of event

reconstruction.

Dark rate was reduced about 10 kH z ! By successful improvement of photocathode, after pulse reduction and so on.

! Comparable level as R3600 considering high QE and CE.

This measurement is quickly and room temperature

(27℃ ), therefore dark rate expected to be lowered by low

temperature and stabilization.

Box& Line PM T has high collection

efficiency and quantum efficiency.

Type PMT serial After pulse

Old ZB8210 0.32±0.03

New EA0037 0.23±0.04

New EA0045 0.04±0.02

New EA0046 0.02±0.01

New EA0047 0±0.02

New EA0052 -0.02±0.02

New EA0053 0.07±0.04

After pulses are coincident signal events

associated with decay electrons via muon decay.

An “After pulse” occasionally

accompanies a primary pulse signal.

• The previous Box&Line PMT (ZB8210) had

showed a large rate of after pulses, about 30%

compared with a primary pulse.

! Recent improvement by Hamamatsu gave

half reduction of the after pulse.

• EA0037 got still high rate, but it is probably

due to the initial production stage.

Performance

Y.Nishimura, R.Akutsu, Y.Suda, M.Nakahata, M.Shiozawa, Y.Hayato, S.Nakayama, H.Tanaka, M.Yokoyama, A.Taketa (The University of Tokyo), Y.Koshio (Okayama University),

Y.Okajima (Tokyo Institute of Technology), M.Jiang, S.Hirota, T.Nakaya (Kyoto University), Y.Kawai, T.Ohmura, M.Suzuki (Hamamatsu Photonics K.K.) Daisuke Fukuda (Okayama university)

! Timing difference was small compared to the timing resolution value. (similar to design)

! Collection efficiency result is similar to that of the or iginal design, however, the

aforementioned deficit appears only along one direction, in this case; thus, it is possible to be

reduced by considering the mounting direction at H yper-K .

• We have developed the Box&Line PMT for Hyper-K.

• The detailed performance evaluation of Box&Line PMT was done.

• As a result, it was shown that Box&Line PMT has better performance than current

Super-K PMT and confirmed to be high performance and sufficient for Hyper-K.

Box& Line PM T has been sharp pulse

shape than R3600

δ = a × EN

Hyper-K uses coils to reduce geomagnetic field, with

the residual magnetic field for the Hyper-K residual at

most a 100 mG level.

50cm Box&Line PMT (R12860) is ready for use in the Hyper-K.

Rate tolerance limit is decided

the coupling condenser in the

bleeder circuit.

Requirement for Hyper-K : Stable gain from

1 p.e. level to several hundreds p.e. level.

up to 1

Summary

Linearity

Dark rate by threshold scan

After pulse

Dark rate vs time run

The performance is evaluated by comparing

“delayed signal with primary” and “delayed

signal without primary”. with varied delay

Recovery

2015/1/2923

•For that events m

ight happen quickly but not keeping so long tim

e such as stopping cosmic

muon

decay, the performance of recovery is

more im

portant

•W

e used two continuous pulse to measure the

gain recovery. •

Observed change of delay pulse charge= (Delay w/ prim

ary) / (Only delay pulse)

Delay

Primary


w/ varied delay


No significant change was observed so far, within 0.5%,which is the sam

e level as measurem

ent error

Two LDs (140p.e. for each)

! Nominal gain (2.2 pC/p.e.).

! 0.25p.e. is about 1mV.

continuously decreasing

All figure are new Box&Line PMTs

0 5 10 15 20 25 30 35 40 45 500

1

2

3

4

Black :EA****(new type)

Blue : ZB**** (old type)

Red : HQE SK-PMT

kHz

Qu

anti

ty

Dark rate of each kinds PMT

Ch

arg

e ra

tio

n :

wit

h /

wit

ho

ut

• Other I mproved PM Ts showed largely reduced

after pulse rate comparable with Super-K PM T.

I mprovement of noise

M agnetic field tolerance

Old type Box&Line PMT(ZB****) was high dark rete ( > 20kHz) and large after pulse.

! Low noise type Box& Line PM T(EA* * * * ) was developed.

! Light power is 1 p.e.

! HV is 2000V

R3600 (SK-PMT)

→ Almost constant in ± 100 mG range

Uniformity of relative collection efficiency

HV [V]1200 1400 1600 1800 2000 2200 2400

Ga

in

0

10

20

30

40

50

606

10´

2.2 pC

ZB8208

ZB8210

ZB8243

ZB8246

ZB8248

ZB8260

Rise time

(10%-90%)

Fall time

(10%-90%)

Pulse width

(FWHM)

R3600 10.6 ns 13.2 ns 18.8 ns

20” High QE Box &

Line PMT (Bleeder A) 6.2 ns 6.3 ns 10.0 ns

20” High QE Box &

Line PMT (Bleeder B) 6.8 ns 15.2ns 13.2 ns

Owning to the development of new bleeder circuit, ringing

effect of new Box&Line PMT is small. (Bleeder B)

Bleeder B was used for this performance evaluation.

δ : Amplification rate of photoelectron

a : Constant

N : Constant

E : High voltage

Six of Box&Line PMT was measured. All Box& Line PM Ts

are consistent with a numerical formula, δ = a × EN.

Pulse shape

R3600

Time [ns]-50 0 50 100 150

Pu

lse h

eig

ht

(No

rma

lize

d)

-1

-0.8

-0.6

-0.4

-0.2

0

R3600



Time [ns]-50 0 50 100 150

Pu

lse

he

ight

(No

rma

lize

d)

-1

-0.8

-0.6

-0.4

-0.2

0

R3600



B&L PMT(bleeder A)

B&L PMT(bleeder B)

B&L PMTs serial

Gain curve

1p.e. resolution Box& Line PM T is more improved

than R3600 in photoelectron and

time resolution.

Peak

Valley

1)p.e)resolu0on

Charge

1p.e. distribution

Charge [photoelectron]-1 0 1 2 3

En

trie

s (

a.u

.)

0

0.2

0.4

0.6

0.8

1

1.2

1.4

R3600


Time (ns)-20 -15 -10 -5 0 5 10 15 20 25

En

trie

s (

a.u

.)

0

0.2

0.4

0.6

0.8

1

R3600


1p.e. resolution Time resolution

Time [ns]-50 0 50 100 150

Pu

lse

he

igh

t (N

orm

alize

d)

-1

-0.8

-0.6

-0.4

-0.2

0

R3600



Time [ns]-50 0 50 100 150

Pu

lse h

eig

ht (N

orm

alize

d)

-1

-0.8

-0.6

-0.4

-0.2

0

R3600



R3600

B&L PMT

R3600

B&L PMT

1p.e. resolution

σ/peak

Peak/

Valley

Timing Resolution

σ FWHM

R3600 53% 2.2 2.1 ns 7.3 ns

B&L PMT 35% 4.3 1.1 ns 4.1 ns

Based on the R3600 setting at Super-Kamiokande, HV of each PMT is set to the

value whose 1 p.e. gain is 2.2 pC.

50cm Box & L ine PM T (Hamamatsu R12860)

•

-

-

•

•

Next generation water Cherenkov detector ! Volume : 0.99Mt (Super-K × 25 in fiducial volume)

! Inner detector photo sensors : 99,000(Super-K:11,129)

! Outer detector photo sensors : 25,000(Super-K:1,885)

! Photo coverage : 20%(Super-K:40%)




2015/1/29 4

e（ 1st

1stdynode


e



Large coverage


Box

line

Enlarging is easy.

+ high QE




2015/1/29 4

e（ 1st

1stdynode


e



Large coverage


Box

line

Enlarging is easy.

+ high QE




2015/1/29 4

e（ 1st

1stdynode


e



Large coverage


Box

line

Enlarging is easy.

+ high QE

Super-K PMT(QE~22%) Box&Line PMT(QE~30%)

R3600 R12860

• Better timing resolution

• Better photoelectron resolution

• High rate tolerance

• Quick gain recovery

• Low noise

• High magnetic field tolerance

Required performance of photo sensors (Box&Line PMT). Need to check the performance

etc…

43cm (17-inch) Box&Line PMT is currently used for KamLand experiment.

! The new Box&Line PMT for Hyper-Kamiokande was developed

to reach 50cm φ effective area and high quantum efficiency.

Recovery

2015/1/29 23




Delay

Primary


w/ varied delay



Gain recovery A quick gain recovery is important to

identify a delayed event in Hyper-K,

such as decay electron from µ.

There were no significant changes observed, and gain is

stable within 0.5% (The gain is statistical fluctuation).

frequency [kHz]500 1000 1500 2000 2500 3000 3500 4000

Att

en

ua

tio

n R

ate

0

0.2

0.4

0.6

0.8

1

1.2

25 p.e.

50 p.e.

100 p.e.

Recovery

2015/1/29 23




Delay

Primary


w/ varied delay



Rate tolerance is necessary for Supernova measurement and so on. ! Supernova of Betelgeuse will bring 10 MHz neutrino interaction at maximum

Gain kept stable, up to 170 µA.

For 1 p.e. signal, the rate can be up to 80 MHz by corresponding above current. (50p.e. can be up to 1.6MHz)

• Most of supernova neutrinos less than 10MHz at maximum bring low energy neutrinos, that is 1 p.e. level for PMT hits.

! Enough tolerance to measure supernova with constant gain.

Am0 100 200 300 400 500 600 700 800

Atte

nu

ation

Ra

te

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

125 p.e.

50 p.e.

100 p.e.

Rate tolerance (pulse frequency) Rate tolerance (charge current)

Gain recovery

Wavelength (nm)300 350 400 450 500 550 600 650 700

Qu

an

tum

effic

ien

cy (

%)

0

5

10

15

20

25

30

35

40

High-QE Box&Line PMT

High-QE Super-K PMT

Normal-QE Super-K PMT

Quantum Efficiency vs. Wavelength

75

50

25

0

-25

-50

-75

Y

X Z

Y

-X

+X

75°

-75°

-75°

75°0°

measurement

point

Angle(deg.) -80 -60 -40 -20 0 20 40 60 80

Re

lative

CE

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

1.1


0mG

+100mG

-100mG


Angle(deg.) -80 -60 -40 -20 0 20 40 60 80

Re

lative

CE

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

1.1


0mG

+100mG

-100mG


Angle(deg.) -80 -60 -40 -20 0 20 40 60 80

Re

lative

CE

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

1.1


0mG

+100mG

-100mG


Angle(deg.) -80 -60 -40 -20 0 20 40 60 80

Re

lative

CE

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

1.1


0mG

+100mG

-100mG


Angle(deg.) -80 -60 -40 -20 0 20 40 60 80

Re

lative

CE

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

1.1


0mG

+100mG

-100mG


Angle(deg.) -80 -60 -40 -20 0 20 40 60 80

Re

lative

CE

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

1.1


0mG

+100mG

-100mG


Angle(deg.) -80 -60 -40 -20 0 20 40 60 80

Re

lative

CE

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

1.1


0mG

+100mG

-100mG


Angle(deg.) -80 -60 -40 -20 0 20 40 60 80

Re

lative

CE

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

1.1


0mG

+100mG

-100mG


Angle(deg.) -80 -60 -40 -20 0 20 40 60 80

T(n

s)

-4

-3

-2

-1

0

1


0mG

+100mG

-100mG


Angle(deg.) -80 -60 -40 -20 0 20 40 60 80

T(n

s)

-4

-3

-2

-1

0

1


0mG

+100mG

-100mG


Angle(deg.) -80 -60 -40 -20 0 20 40 60 80

T(n

s)

-4

-3

-2

-1

0

1


0mG

+100mG

-100mG


Angle(deg.) -80 -60 -40 -20 0 20 40 60 80

T(n

s)

-4

-3

-2

-1

0

1


0mG

+100mG

-100mG


Angle(deg.) -80 -60 -40 -20 0 20 40 60 80

T(n

s)

-4

-3

-2

-1

0

1


0mG

+100mG

-100mG


Angle(deg.) -80 -60 -40 -20 0 20 40 60 80

T(n

s)

-4

-3

-2

-1

0

1


0mG

+100mG

-100mG


Angle(deg.) -80 -60 -40 -20 0 20 40 60 80

T(n

s)

-4

-3

-2

-1

0

1


0mG

+100mG

-100mG


Angle(deg.) -80 -60 -40 -20 0 20 40 60 80

T(n

s)

-4

-3

-2

-1

0

1


0mG

+100mG

-100mG


Difference of signal detection timing Difference of relative Collection Efficiency

! Measurement direction are dynode symmetry direction (X-axis)

and asymmetry direction (Y-axis).

! Measurement point is 0, 25, 50, 75 degree.

! Threshold is 0.25p.e. of 0 mG and 0 degree.

Position dependence

H yper-K amiokande project

! One candidate of photo-sensor is 50cm Box& L ine PM T

Detailed performance evaluation of New 50 cm Photodetectors for Hyper-Kamiokande

Search for Neutrino oscillations, mass hierarchy, nucleon decay, super-nova relic neutrinos. Kajita-san & Arthur B. McDonald got 2015 Novel prize!

Reference – arXiv :1109.3262v1: Letter of Intent : The Hyper-Kamiokande Experiment Detector Design and Physics Potential

Dark rate

Threshold [mV]0 2 4 6 8 10

Da

rk R

ate

[kH

z]

1

10

210

Date06/11 06/18 06/25 07/02

Da

rk R

ate

[kH

z]

9

9.5

10

10.5

11

11.5HV on

After pulse

ns0 10000 20000 30000 40000

Exp

ecte

d n

um

be

r o

f a

fte

rpu

lses/m

ain

pu

lse

*50

0n

s

-0.005

0

0.005

0.01

0.015

0.02Model number

ZB8210

EA0037

EA0045

EA0046

EA0046

EA0052

EA0053

Efficiency

Pulse shape

Gain

L inear ity

Expected Charge [p.e.]0 100 200 300 400 500 600 700 800

Me

asu

red

Cha

rge [

p.e

.]

0

100

200

300

400

500

600

700

800

Rate tolerance

R3600(Super-K PMT)

(Normal photocathode)

Box&Line PMT

(High QE photocathode)

Quantum efficiency ~22% ~30%

Collection efficiency 67% (61%) 95% (85%)

Sensor Efficiency (QE × CE) ~15%(~13%) ~29% (~26%)

The linear ity is kept up to 340 p.e. within gain drop less

than 5% .

The signal of large number of photoelectron ( > 340 p.e.) is

revised by the result.

: φ 460 mm (φ 498 mm)

Dark noise affects an accuracy of event

reconstruction.

Dark rate was reduced about 10 kH z ! By successful improvement of photocathode, after pulse reduction and so on.

! Comparable level as R3600 considering high QE and CE.

This measurement is quickly and room temperature

(27℃ ), therefore dark rate expected to be lowered by low

temperature and stabilization.

Box& Line PM T has high collection

efficiency and quantum efficiency.

Type PMT serial After pulse

Old ZB8210 0.32±0.03

New EA0037 0.23±0.04

New EA0045 0.04±0.02

New EA0046 0.02±0.01

New EA0047 0±0.02

New EA0052 -0.02±0.02

New EA0053 0.07±0.04

After pulses are coincident signal events

associated with decay electrons via muon decay.

An “After pulse” occasionally

accompanies a primary pulse signal.

• The previous Box&Line PMT (ZB8210) had

showed a large rate of after pulses, about 30%

compared with a primary pulse.

! Recent improvement by Hamamatsu gave

half reduction of the after pulse.

• EA0037 got still high rate, but it is probably

due to the initial production stage.

Performance

Y.Nishimura, R.Akutsu, Y.Suda, M.Nakahata, M.Shiozawa, Y.Hayato, S.Nakayama, H.Tanaka, M.Yokoyama, A.Taketa (The University of Tokyo), Y.Koshio (Okayama University),

Y.Okajima (Tokyo Institute of Technology), M.Jiang, S.Hirota, T.Nakaya (Kyoto University), Y.Kawai, T.Ohmura, M.Suzuki (Hamamatsu Photonics K.K.) Daisuke Fukuda (Okayama university)

! Timing difference was small compared to the timing resolution value. (similar to design)

! Collection efficiency result is similar to that of the original design, however, the

aforementioned deficit appears only along one direction, in this case; thus, it is possible to be

reduced by considering the mounting direction at H yper-K .

• We have developed the Box&Line PMT for Hyper-K.

• The detailed performance evaluation of Box&Line PMT was done.

• As a result, it was shown that Box&Line PMT has better performance than current

Super-K PMT and confirmed to be high performance and sufficient for Hyper-K.

Box& Line PM T has been sharp pulse

shape than R3600

δ = a × EN

Hyper-K uses coils to reduce geomagnetic field, with

the residual magnetic field for the Hyper-K residual at

most a 100 mG level.

50cm Box&Line PMT (R12860) is ready for use in the Hyper-K.

Rate tolerance limit is decided

the coupling condenser in the

bleeder circuit.

Requirement for Hyper-K : Stable gain from

1 p.e. level to several hundreds p.e. level.

up to 1

Summary

Linearity

Dark rate by threshold scan

After pulse

Dark rate vs time run

The performance is evaluated by comparing

“delayed signal with primary” and “delayed

signal without primary”. with varied delay

Recovery

2015/1/2923

•For that events m

ight happen quickly but not keeping so long tim

e such as stopping cosmic

muon

decay, the performance of recovery is

more im

portant

•W

e used two continuous pulse to measure the

gain recovery. •

Observed change of delay pulse charge= (Delay w/ prim

ary) / (Only delay pulse)

Delay

Primary


w/ varied delay


No significant change was observed so far, within 0.5%,which is the sam

e level as measurem

ent error

Two LDs (140p.e. for each)

! Nominal gain (2.2 pC/p.e.).

! 0.25p.e. is about 1mV.

continuously decreasing

All figure are new Box&Line PMTs

0 5 10 15 20 25 30 35 40 45 500

1

2

3

4

Black :EA****(new type)

Blue : ZB**** (old type)

Red : HQE SK-PMT

kHz

Qu

anti

ty

Dark rate of each kinds PMT

Ch

arg

e ra

tio

n :

wit

h /

wit

ho

ut

• Other I mproved PM Ts showed largely reduced

after pulse rate comparable with Super-K PM T.

I mprovement of noise

M agnetic field tolerance

Old type Box&Line PMT(ZB****) was high dark rete ( > 20kHz) and large after pulse.

! Low noise type Box& Line PM T(EA* * * * ) was developed.

! Light power is 1 p.e.

! HV is 2000V

R3600 (SK-PMT)

Bx

By

Y

Y

X

X

By

Bx

0 mG0 mG

2000V typical and varied volt. from 1600 to 2200V

Uniformity of various performance was measured in the Helmholtz coil to vary magnetic field.

±100 mG is maximal residual range in HK.

Uniformity of relative transit time

ByBy

BxBx

24

Stability of Gain and Dark Rate (20”)

⚫ Dark rate & after pulse were largely reduced in the latest version after the 3 PMTs.⚫ Stable detection for .

Smooth shift of gain was monitored (Similar tendency to Super-K PMT)

3 High-QE Box&Line PMTs

2014 2015 2016 2017

Rel

ativ

e ga

in

Testing initial type of Box&Line PMTsin 200-ton water Cherenkov detector since 2014.

Working for ~3 years!

2014 2015 2016 2017Dar

k co

un

t ra

te [

kHz]

One Box&Line PMT is getting high rate.

Dark rate is almost constant for 2.5 years. (except for one)

EGADS 200t tankat Kamioka minetoward SK-Gd

7m

25

Cover validation

Sunk down to60m/80m

OsakaNagoya

TokyoGifu

Niigata

SapporoFurano

SK

In Hokkaido, JP

Shaft filled with water

3 x 3 PMTs+ covers1st demonstration test was

performed in 2016 and 2018.

1. Center PMT is imploded by tool. 2. Confirm no damage of central PMT cover

and surrounding PMTs with monitoring

Procedure

4.8mΦ

Pressure gauge

Hit the weakest point

Shock wave monitor in water

Strain gauges

High speedcamera

2 lights

2 lightscamera

PMT

Pre-stress

~70

0m

26

Methods (3” PMT testing)

• Measurements:• Gain, linearity, transit time & TTS, dark rate, position dependences,

afterpulsing, sensitivity to magnetic field, waveform shape

• Differences:• WUT uses PILAS Laser (45 ps, 375 nm) & TEK scope (1GHz, 5GS/s)• QMUL uses CAEN SP5601 LED Driver with OSSV5111A LED (400 nm), VME

SIS3316 digitizer (charge spectrum), pico-scope (min. 1 GS/s rate) for timing measurements

• Working on code to share data between labs in order to cross-check results (almost ready)

LeCroy oscilloscopemin. 350 MHz bandwidth

min. 2 GS/sOwn acquisition software

Selected measurements only

27

Dark Rate (R14347) Results: A. Fiorentini (York Univ.)

Concept of p.e. efficiency:Ratio of pulses with charge over threshold (red) to total

Pedestal

1 p.e.

R14374, S/N BC0032, -HV

R14374, S/N BC0036, +HV

Gain = 5.2E+6

Gain = 5.1E+6

R14374, S/N BC0032 (-HV)

R14374, S/N BC0036 (+HV)

28

Dark Rate (XP82B20) Results: A. Fiorentini (York Univ.)

XP82B20, S/N 80148, -HV

XP82B20, S/N 80149, +HV

XP82B20, S/N 80148, -HV

XP82B20, S/N 80149, +HV

• All PMTs in dark for 48 hours, T = 9 C• Take multiple waveforms with random

trigger, then find and count pulses

29

R14374 - Waveform Shape vs Fiber Slot

30

Light leak?

31

R14374 - Transit Time and TTS

Kashiwa - pulse timing using a digital constant fraction algorithm; York – pulse timing at exactly ½ of pulse amplitudę - trigger to laser pulse delay

TTS (Kashiwa) TTS (York, BC0042)

Transit Time* (Kashiwa) Transit Time (York, BC0042)

TT +

(n

s)

32

Timing Resolution of Sampling Digitizers

• Use AWG instead of PMT.

• Use large reference pulse (timing accuracy 10 ps) and small, shaped signal pulse (1 mV 100 mV).

• Apply signal processing methods and calculate time difference Δtbetween ref. and sig. channels.

• Repeat multiple times and compute RMS of Δt values.

• Two shapers:

– 15 ns and 30 ns rise time (10% to 90%), 5-th order Bessel-type low-pass filters.

AWG

Shaper

ADC

ref. sig.

Agilent 33600A (1 GSPS/80 MHz)

Custom shapers

Commercial ADCs (CAEN)

DT5724(100 MSPS/14b)

V1720 (250 MSPS/12b)

V1730 (500 MSPS/14b)

32

PURPOSE OF THE STUDY:Determine how fast and how precise does a system needs to be to achieve given performance specs?

PMT

Shaper (Low Pass Filter)

Anti-Aliasing (Low Pass Filter)

ADCInterconnects

EMI pickup

Ch

eren

kov

ph

oto

ns

Voltage multiplier (HV supply)

FPGA(signal processing)

Interconnects

EMI pickup

ADC

Power supplies

DAQ= noise source

= EMI (deterministic source)

Voltage multiplier (HV supply) Other FE

modules

Digitization – Waveform Sampling

33

Why do we consider waveform sampling?

PMT base

Frontend board

?

?

• Possibility to implement completely dead-time free system.– Better ability to tag decay electrons that occur at short decay times and high

muon energies.

• Can subtract off periodic EMI by digital filters implemented in FPGA firmware.

• Can disentangle piled-up pulses – Major advantage for intermediate detector

• There is a price to pay: power consumption and cost (?).

Photosensors and Front-end Electronics for the Hyper … · 2018. 7. 31. · Photosensors and...

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Transcript of Photosensors and Front-end Electronics for the Hyper … · 2018. 7. 31. · Photosensors and...