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

WG4 summary

• Film Storage and book-keeping– First version ‘Brick Tracer’ ready to use ( C. Bozza )

• Scanning Quality Control– SUTS ( K. Morishima )– ESS ( C. Bozza )

WG4 summary

Cristiano Bozza – European Emulsion Scanning Group – Nagoya Jan 2008 3

Brick tracer

http://operaweb.web.cern.ch/operaweb/internal/index.shtml

• Cosmic Ray Density– Aim of cosmic ray exposure is to provide alignment for momentu

m 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 ~6micron rms whole OPERA film WITHOUT cosmic rays• Further improvement is being studied. • One can apply this method for Bricks with black CS to have have NO

cosmic ray exposure. • For normal bricks we can use cosmic rays in larger area for alignmen

t.

This method requires a brick should be made of emulsion sheets in a single pack.

WG4 summary

1.4cm x 1.4cm x 11plates

369 tracks in scanning area

dx

(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(1micron).

• Cosmic Ray Density– Aim of cosmic ray exposure is to provide alignment for momentu

m 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 ~6micron rms whole OPERA film WITHOUT cosmic rays• Further improvement is being studied. • One can apply this method for Bricks with black CS to have have NO

cosmic ray exposure. • For normal bricks we can use cosmic rays in larger area for alignmen

t.

This method requires a brick should be made of emulsion sheets in a single pack.

WG4 summary

Deformation map between film 1 - 2 @transportation

50micron

Deformation mapbetween film 1 – 2 @brick

50micron

RMSy=1.4micron

RMSx=2.4micron

difference (transportation - brick)(film 1 – 2)

10micronDeformation seems conserving between transportation and brick.

Virtual alignment

･Used several films of brick:36565 exposed CR･Scanned full area

･ Important to read X-ray mark accuratelyfor accurate alignment

– Trying now

･ Instead of X-ray mark, used tracks at area near the X-ray mark

･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 tracks.

X-ray mark

x

y

1cm

Lea

d dfilm

film

Position difference

offset[micron] = ( -13.2, 2.2 )RMS[micron] = ( 5.8, 5.8 )

Position difference have offset.

[micron] [micron]

dx dy

plate 25 - 26

Prospect for offsetIf films curl at transportationoffset appear.

CRtransportation after scanning

If curl effect contributeoffset should be had same value.

Offset for several combinations

film1 – film2 offset dx[micron]

offset dy[micron]

25 – 26 -13.2 2.2

26 – 27 -17.2 -2.4

27 ｰ 28 -9.7 1.4

Offset is same within several micron.

• 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.

WG4 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 raysOne vertex outside a brick

No CSD tracksTT matchNo Veto tracks

• Shift management and human organization– Homework for each lab

WG4 summary

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 2nd, 3rd,

vertex by cosmic ray.

• --> no cosmic on the ECC with black CS.

• Next talker, Takahashi.ECC downstream

NC event 179312944

Volume scan around vertex

Tracks are visible in veto => This is NOT a neutrino event, but HE cosmics reaction

577748

2938 1211450

After scanback of ~1300 tracks two interesting vertices found

After scanback of ~1300 tracks two interesting vertices found