R

1
RD of Strip/Block Scintillators

• E.P.Jacosalem, S.Iba, N.Nakajima, H.Ono,
• A.L.Sanchez, A.M.Bacala H.Miyata
• GLD Calorimeter Group
• 8th ACFA Workshop on Physics and
• Detector at the Linear Collider
• EXCO, Daegu , Korea
• July 12, 2005

2
Contents

• Introduction
• Research Design and Methodology
• Scintillators length and surface covering
  dependence on Pulse Height (Strip type)
• Position dependence (Strip type)
• Scintillators thickness dependence (Block type)
• Results
• Summary
• Future plan

3
Introduction

• Motivation
• RD 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

4

• 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 Sensor

Photon sensor
Photon sensor

• This study focuses
• small strip and block type sensors
• different surface coverings
• different lengths
• thickness

Photon sensor
Calorimeter Design under construction
5
Research Design Methodology
Setup

• 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

6
Strip Type Scintillator
Research Design Methodology cont..
3M Radiant Mirror Film
Teflon
10x60x2mm
Black Sheet
White Paint with Teflon
White Paint Surface Covering (1.7mm groove for
1.6mm WLS fiber)
Gold Coat

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

White Paint
Aluminum Evaporation
10x40x2mm scintillator (1.4mm groove for 1mm
fiber)
7
Block Type Scintillator
Research Design Methodology cont..

• fiber hole of 1.1mmF at the center
• fiber not pass through the other end (1.0mm
  distance)
• measured the thickness dependence on pulse height.

sketch of block scintillator
8
Research Design and Methodology cont..
To PMT
fitted pulse height

• 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

To PMT
Source point location
9
Results

• 3M radiant mirror film has the greatest pulse
  height.
• There is a trend that pulse height slightly
  increases with sensors length for 3M radiant
  mirror film and Teflon.

10
Results cont..

• 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.

11
Results cont..
Position Dependence along the Strip Scintillator
(2.5 mm from the center)
Position Dependence along the Strip Scintillator
(2.5 mm from the center)

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

12
Results cont..

• dip is 40 corresponds to scint.
  thickness(300microns) f0r 1.6mmF fiber
• small peaks near the fiber (1.6mmF 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.

13
Results cont..
Thickness Dependence of Block Type Scintillator
for Digital Hadron Calorimeter

• 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.

14
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 sensors length for 3M radiant
  mirror film and Teflon.
• 3. 3M radiant mirror film covered scintillators
  using 1.6mmF WLS fiber had about 100 greater
  pulse height compared to scintillators with
  1.0mmF fiber.

15
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 1.6mmF fiber
• 6. Block type scintillators pulse height is
  almost proportional to its thickness

16
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.

Thank you very much...