Gluing machine (scanning at the edge…)

G. Sirri for Bologna Group

G.Sirri – INFN Bologna LNGS 2008-04-03

Intro Whole emulsion area scanning with ESS has been long

discussed. Several R&D has been carried out.

Currently the best solution is to glue the emulsions to an adhesive tape.

This solution allows better working condition also for the plate exchanger.

To be safe for the incoming run, the current suggested strategy is to glue ALL the emulsions.

However, this solution implies remarkable extra work (and cost).

2/7

G.Sirri – INFN Bologna LNGS 2008-04-033/7

Gluing machine

A semi automatic machine to glue emulsion plate on adhesive tape realized by CONMED is now at LNGS.

The output of this machine is a continuous stream of emulsion plates.

Before scanning with ESS, the stream are to be cut to separate plates.

G.Sirri – INFN Bologna LNGS 2008-04-034/7

G.Sirri – INFN Bologna LNGS 2008-04-03

Emulsion

Gluing machine – PVC Frame Solution130

15

Best setup obtained using rigid PVC frames:

Same thickness as emulsion Quite accurate positioning of the corner (validation is in progress). No precise cutting tool required. Emulsion and PVC frame must be manually pre-aligned before gluing. Plastic frames provided by external manufacturer.

CAVEAT: all the operation must be executed in (suitably) clean room to avoid to glue also dust and impurities.

PVC frame

G.Sirri – INFN Bologna LNGS 2008-04-03

Costs and operational times

Gluing machine (duplicate): 8 k€ [6.5 k€ (> 5)]

Tapes and Frames:Acrylic adhesive tape (Nitto Tape NI 3161B):~ 15 euro/brick PVC frame (300 micron) already cut: ~ 4 euro/brick

Operational time (1 person):preparation + gluing + (manual) cut: ~ 30 min/brick

ESS update (~25 vacuum support): ~ 10 k€

G.Sirri – INFN Bologna LNGS 2008-04-037/7

2008-04-032008-04-03

Edge Scanning:Edge Scanning:resolutions, efficiencies resolutions, efficiencies

distortions using new distortions using new plates setting for the ESSplates setting for the ESS

M.Cozzi (Bologna Group)

Data set: 7 consecutive plates (Single Ref) Data set: 7 consecutive plates (Single Ref) exposed @CERN July07 10 GeV pionsexposed @CERN July07 10 GeV pions

s.eY

s.eX

99800

40000

-70000-50000

Scanning area: 2X6 cm2

2 zones selected:

1. Central

2. “edge”

to study:

• scanning quality (distortions)

• base-track efficiency

For different vacuum plate system

60000

90000

3 vaccum systems have been tested:

• Standard plate with vacuum pipe

• Vacuum plate with holes

• Large vacuum pipe with emulsion glued on a tape

Central zone: 2x2 cm2

Edge Zone: 1x2 cm2

Vacuum plates: Vacuum plates: geometry description geometry description

Standard vacuum plateVacuum plate with holes

Glued emulsion larger vacuum pipe= Edge zone ACQ

Standard vacuum plateStandard vacuum plate

Vacuum pipe

Outside the vacuum pipe the emulsion is bend!

s.eY>97500

Vacuum plate with holesVacuum plate with holes

Outside the vacuum holes the emulsion is bend!

Vacuum holes

Glued emulsionGlued emulsion

The emulsion is flat until the edge!

Base-track densityBase-track densityGlued emulsion

Standard vacuum plate

Vacuum plate with holes

Micro-track resolution Micro-track resolution Central zoneCentral zone

Micro-track resolution Micro-track resolution edge zoneedge zone

Glued Emulsion: best resolution (and same as the central zone)

Base-track resolutionBase-track resolutioncentral zonecentral zone

Central zone (2x2 cm2)

Base-track resolutionBase-track resolutionEdge zoneEdge zone

Efficiency – data setEfficiency – data set

Glued

Glued

48

4645

44

43

Eff = N7/(N6+N7)

Exposure angles (rad)

Glued

42

41

Glued

Standard vacuum pipe

48

4645

44

43

Glued

42

41

Glued

Vacuum with holes

Glued

Efficiency have been evaluated on plate 44 for 3 different ACQ setting:

Efficiency pl44 – central zoneEfficiency pl44 – central zone

Efficiency pl44 – “edge” zoneEfficiency pl44 – “edge” zone

DistortionsDistortions

50 micron

D (micron)

^

50 (atan atan )TOP BASEx X XD m i

uur

^

50 (atan atan )TOP BASEy y yD m j

uur

In this calculation we considered only linear distortions. In this approximation we compute the vector D using the following formulas:

x yD D D ur uur uur

Background rejectionBackground rejection

s.eW>14

Large background even after the angular cut around the beam exposure.The “quality cut” eCHI2P vs s.eW cannot be used Quality cut for distortion copmputations: s.eW >14

Distortion near the edge:Distortion near the edge:Standard vacuum plateStandard vacuum plate

Vacuum pipe

20

mra

d

vacuum plate with holesvacuum plate with holes

Distortion near the edge:Distortion near the edge:vacuum plate with holesvacuum plate with holes

20

mra

d

Distortion near the edge:Distortion near the edge:glued emulsion on tapeglued emulsion on tape

20

mra

d

Distortions-central zoneDistortions-central zoneHolesVacuum pipe

20 m

rad

20 m

rad

Distortions – central zoneDistortions – central zoneGlued

20 m

rad

ConclusionsConclusions• The vacuum plate for emulsions glued on a larger

adhesive support allows to scan the whole area of the emulsion with good efficiency and good quality.

• The adhesive tape increase the emulsion distortions (not critical).

• The vacuum plate with holes shows good results in the central zone but the scanning near the edge is critical. No improvements with respect to standard vacuum plates.

G.Sirri – INFN Bologna LNGS 2008-04-03

Vacuum plates

Standard plateplate with holes

Glued emulsion larger vacuum channel= Emulsion

vacuum