WG 4 summary Film Storage and bookkeeping Scanning

WG 4 summary • • • Film Storage and book-keeping Scanning Quality Control Cosmic Ray Density Vertex Confirmation Vertex Location

WG 4 summary • Film Storage and book-keeping – First version ‘Brick Tracer’ ready to use ( C. Bozza ) • Scanning Quality Control – SUTS ( K. Morishima ) – ESS ( C. Bozza )

Brick tracer http: //operaweb. cern. ch/operaweb/internal/index. shtml Cristiano Bozza – European Emulsion Scanning Group – Nagoya Jan 2008 3

WG 4 summary • Cosmic Ray Density – Aim of cosmic ray exposure is to provide alignment for momentum measurement and decay search. – Data shows we can go down to ~1/5 while keeping alignment accuracy. ( A. Ariga ) – Brick deformation can be corrected using Cosmic Rays during transportation ( S. Takahashi ) • now ~6 micron rms whole OPERA film WITHOUT cosmic rays • Further improvement is being studied. • One can apply this method for Bricks with black CS to have NO cosmic ray exposure. • For normal bricks we can use cosmic rays in larger area for alignment. This method requires a brick should be made of emulsion sheets in a single pack.

1. 4 cm x 11 plates dx 369 tracks in scanning area (dx) = sqrt(3/2)* (x) From the point of alignment. Higher cosmic density doesn't give higher resolution. 1/3~1/5 of current exposure is enough to get same alignment accuracy(1 micron).

WG 4 summary • Cosmic Ray Density – Aim of cosmic ray exposure is to provide alignment for momentum measurement and decay search. – Data shows we can go down to ~1/5 while keeping alignment accuracy. ( A. Ariga ) – Brick deformation can be corrected using Cosmic Rays during transportation ( S. Takahashi ) • now ~6 micron rms whole OPERA film WITHOUT cosmic rays • Further improvement is being studied. • One can apply this method for Bricks with black CS to have NO cosmic ray exposure. • For normal bricks we can use cosmic rays in larger area for alignment. This method requires a brick should be made of emulsion sheets in a single pack.

Deformation map between film 1 - 2 @transportation 50 micron

Deformation map between film 1 – 2 @brick 50 micron

difference (transportation - brick) (film 1 – 2) RMSx=2. 4 micron RMSy=1. 4 micron 10 micron Deformation seems conserving between transportation and brick.

Virtual alignment 1 cm X-ray mark ･Used several films of brick: 36565 exposed CR ･Scanned full area ･Important to read X-ray mark accurately for accurate alignment y – Trying now ･Instead of X-ray mark, used tracks at area near the X-ray mark film Lead x d ･Global correction is used tracks at area near the X-ray mark. ･Local correction is used tracks at transportation ･After virtual alignment, I check position difference using brick track

Position difference plate 25 - 26 dx dy [micron] offset[micron] = ( -13. 2, 2. 2 ) RMS[micron] = ( 5. 8, 5. 8 ) Position difference have offset. [micron]

Prospect for offset If films curl at transportation offset appear. transportation CR after scanning If curl effect contribute offset should be had same value.

Offset for several combinations film 1 – film 2 offset dx[micron] offset dy[micron] 25 – 26 -13. 2 26 – 27 -17. 2 -2. 4 27 ｰ 28 -9. 7 1. 4 Offset is same within several micron.

WG 4 summary • Worries about “reducing cosmic ray density” exists … but – Some scan back using X-ray marks were tried also in Europe side. Lyon ( L. Arrabito ) – Cross check can be done soon using brick data taken so far.

WG 4 summary • Vertex Confirmation – Volume scan procedure using SUTS ( T. Fukuda ) – Summary of events Nagoya ( U. Kose, N. Kitagawa ) Bern ( C. Pistillo ) Lyon ( L. Arrabito ) • Vertex Location – NO cosmics for bricks with Black CS Presentations in A. Ariga and S. Takahashi -> Alignment w/o cosmics – Bern NC event ( I. Kreslo ) One vertex related to cosmic rays One vertex outside a brick No CSD tracks TT match No Veto tracks • Shift management and human organization – Homework for each lab

ECC with black CS (current Nagoya strategy. ) 1. General scan the downstream plates(3~5). 2. search vertex candidates. 3. Scanback or Direct vertexing. • Strong worry about the 2 nd, 3 rd, vertex by cosmic ray. ECC with • --> no cosmic on the downstream black CS. • Next talker, Takahashi.