Application of the beta ray alignment for the opera csds
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Application of the Beta-ray alignment for the OPERA CSDs PowerPoint PPT Presentation


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Application of the Beta-ray alignment for the OPERA CSDs. Seigo Miyamoto. Beta-ray alignment. New alignment method by using beta-ray from environmental radioactive isotopes. Coincidence at contacted emulsion layers.

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Application of the Beta-ray alignment for the OPERA CSDs

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Application of theBeta-ray alignment for the OPERA CSDs

Seigo Miyamoto


Beta-ray alignment

  • New alignment method by using beta-ray from environmental radioactive isotopes.

  • Coincidence at contacted emulsion layers.

  • Effective to correct the distortion( is essential for good position resolusion) of film by development or drying .


Detection ofposition displacement peak of beta-ray

-Take all combination of dx in ~+-100um

- Angle allowance is FREE.

2.1um

1.8um


If the tightness of packing is enough,

Position displacement of high energy tracks from beta-ray alignment peak (um)


Application for the OPERA CSD

  • Alignment accuracy is less than 1um.

  • Effective to reject BG tracks very much.

Samples :

Cosmic run events ---- 26 CSDs

Neutrino events ---- 32 CSDs


At first, division of area (5mm x 5mm)


Procedure

Taking all combinations of MicroTracks in contacted layers,

And Detection of beta-ray alignment peaks in each unit areas.

Position displacement distribution from the X-ray alignment


Plot vector as the center of peak in each unit area on the film map -> Relative Distortion map.

40 um

20um in delta position space


Some Samples


Some Samples


Some Samples


Some Samples


Some Samples


Estimation of successful area

  • Continuity check is suitable which beta-ray alignment is success or not because distortion should be continual.

  • Check the difference of vector between adjacent area.

  • For example,

  • d(dX)(a,b)=dXb-dXa

  • - if d(dX) < 10umfor >=2 adjacent areas, “a” is defined as continual(successful).

b

c

e

a

d


beta-ray alignment summary


Continual area ratio of CSDs

sucessful

sucessful


The reason of below 90%

  • Not enough beta-rays to align.

    ---- 1

  • Peak is detected, but double.

    ---- 5

  • Large Gap exists.

    ---- 1


Examples , Double Peak


Examples , Double Peak


Examples , Double Peak


Examples , Double Peak


Examples , Large Gap is Detected.


Examples , Large Gap is Detected.


Examples , Large Gap is Detected.


Summary

  • Beta-ray alignment was applied to real OPERA Experiment.

  • The number of beta-ray for alignment is enough.

  • We estimated mechanical tightness. 26/32 CSDs is aligned successfully. 5/32 CSDs have Double Peaks, these are recoverable by detection both (We have 2 alignments, BG Doublet tracks become twice).

    1/32 CSD has large (more than 100um) gap, we can detect it.

  • We continue the study of these 6 events.


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