1

PMT & Disc. Board Test

1. Plateau curve

2. Discriminator board test

Dan, Octavia, Heejong4/15/2008

2

1. PMT Plateau curve

Disc. Threshold 100mV( 4/8(Tues))

High Voltage(V) of PMT A 800 900 1000 1100 1200 1300 1400 1500

Nor

mal

ized

Rat

io o

f C

ount

s( (

A*B

)/B

0

0.002

0.004

0.006

0.008

0.01

Plateau of PMT A: (A*B)/B Plateau of PMT A: (A*B)/B

High Voltage(V) of PMT B 800 900 1000 1100 1200 1300 1400 1500

Nor

mal

ized

Rat

io o

f C

ount

s( (

B*A

)/A

0

0.002

0.004

0.006

0.008

0.01

Plateau of PMT B : (B*A)/A Plateau of PMT B : (B*A)/A

-1300V seems optimal value for PMT operation.

3

Disc. Threshold 300mV (4/9(Wed))

High Voltage(V) of PMT A 800 900 1000 1100 1200 1300 1400 1500

Nor

mal

ized

Rat

io o

f C

ount

s( (

A*B

)/B

0

0.001

0.002

0.003

0.004

0.005

0.006

Plateau of PMT A: (A*B)/B Plateau of PMT A: (A*B)/B

High Voltage(V) of PMT B 800 900 1000 1100 1200 1300 1400 1500

Nor

mal

ized

Rat

io o

f C

ount

s( (

B*A

)/A

0

0.001

0.002

0.003

0.004

0.005

0.006

Plateau of PMT B : (B*A)/A Plateau of PMT B : (B*A)/A

4

Disc. Threshold 60mV( 4/10(Thurs))

High Voltage(V) of PMT A 800 900 1000 1100 1200 1300 1400 1500

Nor

mal

ized

Rat

io o

f C

ount

s( (

A*B

)/B

0

0.002

0.004

0.006

0.008

0.01

Plateau of PMT A: (A*B)/B Plateau of PMT A: (A*B)/B

High Voltage(V) of PMT B 800 900 1000 1100 1200 1300 1400 1500

Nor

mal

ized

Rat

io o

f C

ount

s( (

B*A

)/A

0

0.002

0.004

0.006

0.008

0.01

Plateau of PMT B : (B*A)/A Plateau of PMT B : (B*A)/A

5

2. Discriminator Board Test

PurposeThreshold set

Input

Ch1 +,- output

Timing resolution,Rise time

1 Board 4 channelsOnly 2 channels tested.

6

Setup

1. Input source: from pulse generator.

800mV with ~2.3ns rise time.

2. Fed to input of disc. Board.

3. Ch1+,- & Ch2+,- were connected to the Tektronix 6154 Oscilloscope for data recording.

4. 50ps sample interval

1000 sampling for each channels

2000 events

5. Two data set.

(a) 100, 100mV threshold for ch1, ch2

(b) 100, 500mV threshold for ch1, ch2

7

Sample event

Time(ns)0 10 20 30 40 50

Am

plitu

de(m

V)

800

900

1000

1100

1200

1300

1400

Event# 0 : Disc1 +Event# 0 : Disc1 +

Time(ns)0 10 20 30 40 50

Am

plitu

de(m

V)

800

900

1000

1100

1200

1300

1400

Event# 0 : Disc2 +Event# 0 : Disc2 +

Time(ns)0 10 20 30 40 50

Am

plitu

de(m

V)

800

900

1000

1100

1200

1300

1400

Event# 0 : Disc1 --Event# 0 : Disc1 --

Time(ns)0 10 20 30 40 50

Am

plitu

de(m

V)

800

900

1000

1100

1200

1300

1400

Event# 0 : Disc2 --Event# 0 : Disc2 --

Time(ns)0 10 20 30 40 50

Am

plitu

de(m

V)

-400

-200

0

200

400

Event# 0 : Diff1( Pos - Neg)Event# 0 : Diff1( Pos - Neg)

Time(ns)0 10 20 30 40 50

Am

plitu

de(m

V)

-400

-200

0

200

400

Event# 0 : Diff2( Pos - Neg)Event# 0 : Diff2( Pos - Neg)

~45ns width of Differential Signal.50ps sampling interval, 1000 samplingPositive, Negative, ( Positive – Negative)100, 100mV thresholds

8

Close up of the first 5ns region

Time(ns)1 1.5 2 2.5 3 3.5 4 4.5

Am

plitu

de(m

V)

800

900

1000

1100

1200

1300

1400Event# 0 : Disc1 +Event# 0 : Disc1 +

Time(ns)1 1.5 2 2.5 3 3.5 4 4.5

Am

plitu

de(m

V)

800

900

1000

1100

1200

1300

1400Event# 0 : Disc2 +Event# 0 : Disc2 +

Time(ns)1 1.5 2 2.5 3 3.5 4 4.5

Am

plitu

de(m

V)

800

900

1000

1100

1200

1300

1400Event# 0 : Disc1 --Event# 0 : Disc1 --

Time(ns)1 1.5 2 2.5 3 3.5 4 4.5

Am

plitu

de(m

V)

800

900

1000

1100

1200

1300

1400Event# 0 : Disc2 --Event# 0 : Disc2 --

Time(ns)1 1.5 2 2.5 3 3.5 4 4.5

Am

plitu

de(m

V)

-400

-200

0

200

400

Event# 0 : Diff1( Pos - Neg)Event# 0 : Diff1( Pos - Neg)

Time(ns)1 1.5 2 2.5 3 3.5 4 4.5

Am

plitu

de(m

V)

-400

-200

0

200

400

Event# 0 : Diff2( Pos - Neg)Event# 0 : Diff2( Pos - Neg)

9

Simple Trial to get timing

Time(ns)0 10 20 30 40 50

Am

plitu

de(m

V)

-400

-200

0

200

400

Event# 0 : Diff1( Pos - Neg)Event# 0 : Diff1( Pos - Neg)

Time(ns)0 10 20 30 40 50

Am

plitu

de(m

V)

-400

-200

0

200

400

Event# 0 : Diff2( Pos - Neg)Event# 0 : Diff2( Pos - Neg)

Time(ns)0.5 1 1.5 2 2.5 3 3.5 4 4.5

Am

plitu

de(m

V)

-400

-200

0

200

400

Event# 0 : Diff1( Pos - Neg)Event# 0 : Diff1( Pos - Neg)

Time(ns)0.5 1 1.5 2 2.5 3 3.5 4 4.5

Am

plitu

de(m

V)

-400

-200

0

200

400

Event# 0 : Diff2( Pos - Neg)Event# 0 : Diff2( Pos - Neg)

Linear fit in 3 regions( Base, Slope, Top)Take the intercepting points as references.T_a100, T_b100

10

Timing difference between channels with 100,100mV threshold

2 2.2 2.4 2.6 2.8 3 3.2 3.4 3.6 3.8 40

50

100

150

200

250

300

350

400

Timing of Ch#1 Entries 2000

Mean 2.851

RMS 0.01997

Integral 2000

Timing of Ch#1

2 2.2 2.4 2.6 2.8 3 3.2 3.4 3.6 3.8 40

50

100

150

200

250

300

350

400

Timing of Ch#2 Entries 2000

Mean 2.594

RMS 0.01869

Integral 2000

Timing of Ch#2

0.2 0.25 0.3 0.35 0.40

50

100

150

200

250

300

350

Ch#1 - Ch#2 Entries 2000Mean 0.2571RMS 0.01138Integral 2000

/ ndf 2χ 19.43 / 14Constant 9.8± 359.9

Mean 0.0002± 0.2572 Sigma 0.00017± 0.01097

Ch#1 - Ch#2

Sigma(T_a100 – T_b100) = 11ps

11

Effect of Threshold changeat 100, 500mV

Time(ns)0 10 20 30 40 50

Am

plitu

de(m

V)

-400

-200

0

200

400

Event# 0 : Diff1( Pos - Neg)Event# 0 : Diff1( Pos - Neg)

Time(ns)0 10 20 30 40 50

Am

plitu

de(m

V)

-400

-200

0

200

400

Event# 0 : Diff2( Pos - Neg)Event# 0 : Diff2( Pos - Neg)

Time(ns)0.5 1 1.5 2 2.5 3 3.5 4 4.5

Am

plitu

de(m

V)

-400

-200

0

200

400

Event# 0 : Diff1( Pos - Neg)Event# 0 : Diff1( Pos - Neg)

Time(ns)0.5 1 1.5 2 2.5 3 3.5 4 4.5

Am

plitu

de(m

V)

-400

-200

0

200

400

Event# 0 : Diff2( Pos - Neg)Event# 0 : Diff2( Pos - Neg)

Same procedure as for 100, 100mV.T_a100, T_b500

12

Timing difference between channels with 100,500mV threshold

2 2.2 2.4 2.6 2.8 3 3.2 3.4 3.6 3.8 40

50

100

150

200

250

300

350

400

Timing of Ch#1 Entries 2000

Mean 2.83

RMS 0.02075

Integral 2000

Timing of Ch#1

2 2.2 2.4 2.6 2.8 3 3.2 3.4 3.6 3.8 40

50

100

150

200

250

300

Timing of Ch#2 Entries 2000

Mean 3.751

RMS 0.02638

Integral 2000

Timing of Ch#2

-1 -0.95 -0.9 -0.85 -0.8 -0.750

50

100

150

200

250

Ch#1 - Ch#2 Entries 2000

Mean -0.9209

RMS 0.01497

Integral 2000

/ ndf 2χ 53.55 / 19

Constant 7.9± 277.6

Mean 0.0003± -0.9206

Sigma 0.00024± 0.01399

Ch#1 - Ch#2

Sigma(T_a100 – T_b500) = 14psSlightly worse than 11ps.Effect of different pulse heights?

13

Timing difference between channels with 100, 500mV threshold

(T_a100 – T_b100) – ( T_a100 – T_b500)0.25 – (-0.92) = 1.17 ns due to 400mV threshold change.

Consistent with 800mV pulse( ~2.5 rise time)

Timing difference between channels has the resolution of~11ps( ~26ps in FWHM).

14

Estimation of rise time

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10

20

40

60

80

100

120

140

Rise Time of Ch#1 Entries 2000

Mean 0.358

RMS 0.03443

Integral 2000

Rise Time of Ch#1

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10

20

40

60

80

100

120

140

160

180

Rise Time of Ch#2 Entries 2000

Mean 0.3615

RMS 0.02412

Integral 2000

Rise Time of Ch#2

Rise time = time from 10% to 90% of pulse height.= 360ps*0.8 = ~290ps

15

Timing analysis

Time(ns)0 20 40 60 80 100 120 140 160 180 200

Am

plitu

de(m

V)

600

800

1000

1200

1400

Event# 0 : Disc1 +Event# 0 : Disc1 +

Time(ns)0 20 40 60 80 100 120 140 160 180 200

Am

plitu

de(m

V)

600

800

1000

1200

1400

Event# 0 : Disc2 +Event# 0 : Disc2 +

Time(ns)0 20 40 60 80 100 120 140 160 180 200

Am

plitu

de(m

V)

-800

-700

-600

-500

-400

-300

-200

-100

0

100

Event# 0 : PMT AEvent# 0 : PMT A

Time(ns)28 30 32 34 36 38 40 42 44 46

Am

plitu

de(m

V)

-800

-700

-600

-500

-400

-300

-200

-100

0

100

Event# 0 : PMT AEvent# 0 : PMT A

Can try multi thresholds method.PMT A signal, Disc1(+), Disc2(-), Coincidence(PMT A &B) for trigger.Limited by Oscilloscope channels ( 4 inputs).

16

Plans

1. remaining channels of discriminator board.

2. Timing Analysis.( PMT + disc. Board)

3. PMTs + Disc. Board + HPTDC &

readout timing + pulse height data

using Labview environment.