New grid reference system using photomask Toho Univ M.Kimura, C.Fukushima, H.Shibuya, S.Ogawa Emulsion Workshop 8 th 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 = 1.5  m×1.5  m 5  m×5  m 15  m×15  m Interval = 200  m Base material = quartz CTE = Photomask 1/20 x Soda lime glass Mask picture （ x10 ） Photomask is produced using semi-conductor techniques

Top view Side view 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 area 2.Calculate affine parameters 3.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 measurements of each spot positions 6.Calculate the difference from the average of four rotational position measurements

The average of difference from design value The largest difference ～ 3  m

The difference from the average of each measurement at four rotational positions Photomask have good rotational symmetries  = 0.29  m  = 0.22  m  = 0.32  m  = 0.22  m  = 0.25  m  = 0.24  m  = 0.22  m x x x x y y y y All rotation angle →  ～ 0.3  m 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  ～ 0.3  m The largest difference is ～ 3  m 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 = 50  m Interval = 1cm Base material = polyester CTE = Photomask Diameter = 10  m Interval = 500  m Base = soda-lime glass CTE =

After contact printing （ x10 ）（ x50 ） 100  m Contact print to OPERA film （ Old mask ）

Distortion of OPERA film （ Old photomask ） area side length in mm Distortion size in  m OPERA film Photomask Ultra thin film （ 40  m base + 10  m 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  2  beam 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