Gluing machine (scanning at the edge…) G. Sirri for Bologna Group

G.Sirri – INFN Bologna LNGS 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 /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 /7

G.Sirri – INFN Bologna LNGS Emulsion Gluing machine – PVC Frame Solution 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 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 /7

Edge Scanning: resolutions, efficiencies distortions using new plates setting for the ESS M.Cozzi (Bologna Group)

Data set: 7 consecutive plates (Single Ref) July07 10 GeV pions s.eY s.eX Scanning area: 2X6 cm 2 2 zones selected: 1.Central 2.“edge” to study: scanning quality (distortions) base-track efficiency For different vacuum plate system 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: geometry description Standard vacuum plate Vacuum plate with holes Glued emulsion larger vacuum pipe = Edge zone ACQ

Standard vacuum plate Vacuum pipe Outside the vacuum pipe the emulsion is bend! s.eY>97500

Vacuum plate with holes Outside the vacuum holes the emulsion is bend! Vacuum holes

Glued emulsion The emulsion is flat until the edge!

Base-track density Glued emulsion Standard vacuum plate Vacuum plate with holes

Micro-track resolution Central zone

Micro-track resolution edge zone Glued Emulsion: best resolution (and same as the central zone)

Base-track resolution central zone Central zone (2x2 cm 2 )

Base-track resolution Edge zone

Efficiency – data set Glued Eff = N7/(N6+N7) Exposure angles (rad) Glued Glued Standard vacuum pipe Glued Glued Vacuum with holes Glued Efficiency have been evaluated on plate 44 for 3 different ACQ setting:

Efficiency pl44 – central zone

Efficiency pl44 – “edge” zone

Distortions 50 micron D (micron) In this calculation we considered only linear distortions. In this approximation we compute the vector D using the following formulas:

Background 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: Standard vacuum plate Vacuum pipe 20 mrad

vacuum plate with holes

Distortion near the edge: vacuum plate with holes 20 mrad

Distortion near the edge: glued emulsion on tape 20 mrad

Distortions-central zone Holes Vacuum pipe 20 mrad

Distortions – central zone Glued 20 mrad

Conclusions 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 Vacuum plates Standard plate plate with holes Glued emulsion larger vacuum channel = Emulsion vacuum