Edge Scanning: new Edge Scanning: new plate design for the plate design for the European Scanning European Scanning

SystemSystem

G. Sirri for Bologna group

22/17/17

Specifications of the glass window

10 cm

10 μm

THICKNESS TOLERANCE:< 10 μm per 10 cm length

FLATNESS:a few fringes per inch(~400 nm per cm)( local slope < 0.1 mrad)

PARALLELISM:< 3 arc min (1 mrad)

a few fringes per inch

Specifications:

• This window is produced by Silo (Florence) according to the following specifications:

44/17/17

““Standard” vacuum plateStandard” vacuum plate

125.1

99.8

118 mm

95 mm

D1 = 3.5 mm

D2 = 2.5 mm

~10% of the emulsion plate is outside the vacuum pipe.

groove for vacuum

55/17/17

New vacuum plate for the European Scanning Sysyem to scan the whole area of the emulsion plate.

125.1 (max 125.5, min 124.55)

99.8 (max 100.0, m

in 99.45)

128 mm

102 mm

The emulsion is glued on a larger adhesive support (similar to the Nagoya Plate Changer) in order to keep it steady during scanning.

66/17/17

groove for vacuum

Plate setting with adhesive Plate setting with adhesive support support

Adhesive support on the bottom side

Several adhesive support tested:

Type Thickness

Nitto tape 31RH 72 μm

Nitto tape 31 BATR 71 μm

Nitto tape 5058A5 45 μm

3M tape 76991 47 μm

3M Electrostatic tape

150 μm

very adhesive

Enough adhesiveNot adhesive,problems

scanning with oilSufficiently adhesive and very transparentSufficiently adhesive, problems on the edge

scaning with oil

Emulsions manually glued to the support, having care to minimize troubles in scanning the bottom side (as micrometric air bubbles).

Emulsion

(thanks to japanese collegues and N. D’Ambrosio to provide us a sample of the adhesive tapes)

77/17/17

Data setData setBrick exposed in the cosmic ray pit for 4.75 days. Ref. efficiency on the center of the emulsions:~80 % 5 plates have been glued to adhesive tapes:2021 Nitto tape 31 RH2223 Nitto tape 31 BATR2425 Nitto tape 5058A52627 3M tape 769912829 Electrostatic tape30

glass

All the others attached to the plate with a scotch tape (covering about 1 mm of the edge); some of them have been measured also using a “standard” plate.

glass

ODD PLATES

EVEN PLATES

emulsion

emulsion tape

tape

88/17/17

Data acqData acq

Y (m)

X(m)

99500

69000

3000060000

glass

3X3 cm2 on each plate

to test:

1. the scanning quality (distortions and efficiencies) with and without the adhesive support

2. base-track efficiency on the edge of the emulsions

99/17/17

DistortionsDistortionstop- base

position (m)

3 mm from the edge

P25

P22

P23

P20

P21

P24

-0.020 mrad

-0.020 mrad

-0.015 mrad

1010/17/17

Distortions near the edgeDistortions near the edge

Starting from 3 mm from the edge, distrortions are bad. We have 20 mrad for all plates, with or without the support.

1 cm from the edge

1111/17/17

Efficiencies vs Plate Efficiencies vs Plate (not edge)(not edge)(d>1 cm from the edge)(d>1 cm from the edge)

Nitto tape 31 RH

Nitto tape 31 BA TR

Nitto tape 5058A5

3M tape 76991

Electrostatic tape

No support

1212/17/17

Efficiencies Efficiencies (not edge)(not edge)

Average for all plates

1313/17/17

Base-track density near the edge Base-track density near the edge (d<1cm)(d<1cm)

X (m)

Y (m

)

“Standard” vacuum plate

The vacuum groove is visible as a zone with a huge number of fake tracks. Outside we can still measure some tracks but volume-tracks are not well reconstructed.

New vacuum plate (emulsions with adhesive support)

We can measure the whole area of the emulsions.

1414/17/17

Efficiencies Efficiencies near the edgenear the edge

Average for all plates with adhesive support

2927252321

1515/17/17

Efficiencies Efficiencies near the edgenear the edge

o New plate, emulsion with adhesive support (Nitto tape 31 BA TR)

“standard” plate

Vacuum groove

Outside the efficiency decrease to zero.

1616/17/17

New plate without supportNew plate without support

The emulsion is not stable enough on the plate. The tape on the top side of the emulsion is fine to scan far away from the edge. Close to the edge, specially with oil, the system looses surfaces and miss some fragments.

Plate 26 Plate 24

Plate 28

1717/17/17

ConclusionsConclusions• The new vacuum plate allows to use

emulsions glued on a larger adhesive support and to scan the whole area of the emulsion.

• All the adhesive tapes we tested don’t decrease the quality of the acq.

• Efficiency is good close to the edge, with respect to the “standard” plate.

• Strong distortions from 3 mm far to the edge, related to emulsion itself.