New grid reference system using photomask

Toho Univ

M.Kimura, C.Fukushima, H.Shibuya, S.Ogawa

Emulsion Workshop 8th Dec 2006

Introduction

• We developed good grid reference system for studying distortion of OPERA film

• We produced gridmark using semi-conductor technology (called “photomask”)

• We evaluated the quality of the grid reference system based on photomask

Specifications

• Pattern area size =

12.7cm×12.7cm

• Square spot =

1.5m×1.5m

5m×5m 　

　　　　 15m×15m

• Interval = 200m

• Base material = quartz• CTE =

Photomask

17105.5 K

1/20 x Soda lime glassMask picture （ x10 ）

Photomask is produced using semi-conductor techniques

Top view

Side view

15.2cm （ 6 inch ）

15.2cm （ 6 inch ）

7mm

quality check

Measurement of spot positions on the photomask

1. Measure X,Y coordinates of four spots at corners of the area2. Calculate affine parameters3. Measure spot positions inside the area (12cmx12cm: 13x13 = 169 points) 4. Repeat procedure 1-3 with rotating photomask(0, 90, 180, 270 deg) 5. Calculate the average of difference from design value of four measu

rements of each spot positions6. Calculate the difference from the average of four rotational position

measurements

The average of difference from design value

The largest difference ～ 3m

The difference from the average of each measurement at four rotational positions

Photomask have good rotational symmetries

= 0.29m = 0.22m

= 0.22m= 0.32m

= 0.22m

= 0.25m

= 0.24m

= 0.22m

x

x

x

x

y

y

y

y

All rotation angle → ～ 0.3m

0 deg

90 deg

180 deg

270 deg

Summary

• We produced photomask to measure distortion properties of emulsion film

• Checked quality of photomask by observed rotational symmetries

• Any rotation angle, difference between measured and averaged positions is ～ 0.3m

• The largest difference is ～ 3m in 12cm×12cm

• If photomask is produced as designed, average difference should be due to stage distortion

Backup

Right angle gauge

Old photomask

Mask picture(x10)

Mask used DONUT exp

• Diameter = 50m

• Interval = 1cm

• Base material = polyester• CTE =

15105.2 K

Photomask

• Diameter = 10m

• Interval = 500m

• Base = soda-lime glass • CTE =

16100.9 K

After contact

printing （ x10 ）（ x50 ）

100m

100m

Contact print to OPERA film （ Old mask ）

Distortion of OPERA film （ Old photomask ）

area side length in mm

Distortion size in mOPERA film

Photomask

Ultra thin film （ 40m base + 10m em ）

Relationship of area size and distortion （ However,

at central part of OPERA film ）

Research area is small → distortion becomes small

→ improvement of p/p⊿

Momentum measurement using MCS

Cell length

4GeV/c at 2beam line KEK （ 2001 ）

Displacement (m)

Future plan

• Establish condition of the contact printing

　 light source selection etc…

• Beam test

　 check improvement of p/p （ ECC + photomask ）

• Develop Totally-automated printing line