R&D of Strip/Block Scintillators E.P.Jacosalem, S.Iba, N.Nakajima, H.Ono, A.L.Sanchez, A.M.Bacala & H.Miyata GLD Calorimeter Group 8 th ACFA Workshop on.

R&D of Strip/Block Scintillators

E.P.Jacosalem, S.Iba, N.Nakajima, H.Ono,

A.L.Sanchez, A.M.Bacala & H.MiyataGLD Calorimeter Group

8th ACFA Workshop on Physics andDetector at the Linear Collider

EXCO, Daegu , KoreaJuly 12, 2005

Contents:

Introduction Research Design and Methodology

Scintillator’s length and surface covering dependence on Pulse Height (Strip type)

Position dependence (Strip type) Scintillator’s thickness dependence (Block

type) Results Summary Future plan

Motivation R&D for new calorimeters Needs fine segmentation Small scintillators

Calorimeter Designs (GLD) Past and Existing

Layers of strip type plastic scintillators (10x200x2mm) Layers of tile type scintillators (40x40x1mm) PMT as read out WLS Fiber

Under construction Stack of Z-layer + X-layer strip scintillators

(10x200x2mm) + Tile-layer (40x40x1mm) Absorber placed in between layers SiPM/MPC (Multi pixels Photon Counter) as read out WLS fiber

Introduction

Calorimeter Design under construction

New design? smaller scintillators

strip type for EM and hadron analog calorimeter

block type for digital hadron calorimeter

best light collection efficiency

WLS fiber

Photon SensorPhoton sensor

Photon sensor

Photon sensor

This study focuses

small strip and block type sensors

different surface coverings

different lengths

thickness

• Sensor : Strip type scintillator ( length: 4,8,12, 16cm) Block type scintillator (thickness: 2, 4, 5, 6 and 8mm)• Trigger : Scintillator (about 1cmx8cmx5mm ) directly connected to PMT • Source : 90Sr (beta-ray)• WLS fiber diameter: 1.0mm ; 1.6mm (length: 20 cm)• PMT (sensor) : 16 Ch MAPMT H6568-10, HV : -950V• PMT (trigger) : H3164, HV : -900V

Setup

Research Design & Methodology

3M Radiant Mirror Film

Teflon

Black Sheet

White Paint with Teflon

Gold Coat

White Paint

Aluminum Evaporation

White Paint Surface Covering (1.7mm groove for 1.6mm WLS fiber)

10x60x2mm

Strip Type Scintillator

10x40x2mm scintillator (1.4mm groove for 1mm fiber)

10x160x2mm

10x80x2mm

10x40x2mm

10x120x2mm

Research Design & Methodology cont..

Compared each type using ADC system Used WLS fiber with diameter of 1.0mm and 1.6mmDetermined the systematic error

Research Design & Methodology cont..

Block Type Scintillator

10x10mm teflon-wrapped scintillator

8mm thick6mm thick 5mm

thick4mm thick

2mm thick

fiber hole of 1.1mmΦ at the center

fiber not pass through the other end (1.0mm distance)

measured the thickness dependence on pulse height.

sketch of block scintillator

Signal Pulse Height

pedestal

signal

Source point location

Plotted the pulse height (ADC Counts) vs. sensors length with different surface covering

Measured and plotted the position dependence across and along the strip scintillator

Research Design and Methodology cont..

fitted pulse height

10mm

2.5 mm

Top view

Strip-type Sensor

Source point

To PMT

Top view

5.0mm

2.5mm

Block-type Sensor

Source point

To PMT

To PMT

Results:

3M radiant mirror film has the greatest pulse height.

There is a trend that pulse height slightly increases with sensor’s length for 3M radiant mirror film and Teflon.

Syst error

20 mm 40 mm 80 mm 120 mm 160 mm0

102030405060708090

100110120130140150

Sensor's Length and Surface Covering DependenceWLS fiber dia: 1.0mm

3M Radiant Mirror Film

Teflon

Aluminum Evaporation

White Paint with teflon

White Paint

Black Sheet

Gold

Sensor's Length

Pul

se H

eig

ht

(AD

C C

ounts

)

3M radiant mirror film

Teflon

White paint with teflon

White paint

Aluminum evaporation

Black sheet

Gold

3M radiant mirror film

Teflon

White paint with teflon

White paint

Aluminum evaporation

Black sheet

Gold

3M radiant mirror film has greatest pulse height.

3M radiant mirror film and teflon wrapped scintillators showed that good total reflection occurred when thin air gap is present between reflector and scintillator.

Results cont..

20 mm 40 mm 80 mm 120 mm 160 mm 180 mm

0

25

50

75

100

125

150

175

200

225

Sensor's Length and Surface Covering DependenceWLS fiber dia: 1.6mm

3M Radiant Mir-ror Film

Teflon

Aluminum Evaporation

White Paint with teflon

White Paint

Black Sheet

Sensor's Length

PU

lse

He

igh

t (A

DC

Co

un

ts)

syst error

3M radiant mirror film

Teflon

White paint with teflon

White paint

Aluminum evaporation

Black sheet

Results cont..

PMT

1.6mmΦ WLS_3Mmirror film

1.0mmΦ WLS_3Mmirror film

1.6mmΦ WLS_ Teflon

1.0mmΦ WLS_ Teflon

Position dependence along the strip scintillator showed the uniformity of light transmission from the sensor to PMT.

Keyhole

measurementalong the strip

WLS fiber

measurement across the strip

Position Dependence along the Strip Scintillator (2.5 mm from the center)Position Dependence along the Strip Scintillator (2.5 mm from the center)

small peaks

Position Dependence across the Strip Scint (3M radiant film)

Results cont..

‘dip’ is 40% corresponds to scint. thickness(300microns) f0r 1.6mmΦ fiber

small peaks near the fiber (1.6mmΦ fiber)

no significant difference on pulse height values across the strip at 2 different locations (20mm and 10 mm from end)

light yield increases about 100% as fiber diameter is increased from 1.0mm to 1.6mm for 3M radiant mirror film.

Fiber diameter

1.6mm

1mm

1.6mmΦ WLS ; source positioned @ 10 (bl) and 20mm (gr) from the far end

1mmΦ WLS ; source positioned @ 10mm (bl) and 20mm (r) from the far end

Results cont..

3M radiant mirror film

Teflon

No peak observed at 8mm thick.

Pulse height almost proportional with scint thickness for 3M radiant mirror film.

Light output at 6mm is larger than that of strip scint (10x40x2mm) then the block scint is enough for digital hadron calorimeter.

Thickness Dependence of Block Type Scintillator for Digital Hadron Calorimeter

Summary

1. 3M radiant mirror film covered scintillator found to have the greatest pulse height for both WLS fiber diameters (1.0 & 1.6mm).

2. There is a trend that pulse height slightly increases with sensor’s length for 3M radiant mirror film and Teflon.

3. 3M radiant mirror film covered scintillators using 1.6mmΦ WLS fiber had about 100% greater pulse height compared to scintillators with 1.0mmΦ fiber.

Summary cont..

4. Position dependence along the strip scintillator showed the uniformity of light transmission from the sensor to PMT for 3M radiant mirror film and teflon wrapped scintillators.

5. ‘dip’ is 40% corresponds to scint. thickness(300microns) for 1.6mmΦ fiber

6. Block type scintillator’s pulse height is almost proportional to its thickness

Future plans

Do simulation for light transmission for the strip and block type scintillator.

Test the best light yield scintillator using photon sensor (MPC/SiPM) as read out through WLS fiber.