Changeable Sheet

A.Ariga , Nagoya univ

CS strategy• R&D ~2004-Oct

– BG rejection• Distortion distortion itself, precise measurement,

packing• Self-Refresh parameter study

– Aging test at high humidity• sensitivity , fog , etc.

• CS packing machine development ~2004-May• Production 2005-May ~ 1000CS/day

– Humid packing at Nagoya.– Initialization at Gran Sasso (self-refresh acceleration,

30degC 1month etc).

• Install– BAM,BMS

BG rejection by Microtrack-angle resolution improvement.

NBG (θ∝ allowance)4

Distortion Study

θallowance is decided by distortion. at present, maximum 50mrad.

Distortion study for CS.• How can we make good quality CS stably?

– must study develop on the view of distortion.

• Measures against...– Stripe distortion in FIX.– Reticulation in STOP.– Bubbles in Wash.– Glycerin non-uniformity.

• the limit of stage error.

Test Sample• film

– Non-Refreshed

– Refreshed

• exposure– 2GeV pion at KEK

– ~105 particle / cm2

low humidity packed

Stripe shape Distortion

4mm

Distortion by Stripe of emulsion surface.

Position X

x =

Mic

rotr

ack -

B

aset

rack

Amplitude = 10mrad

Direction of Stripe

it depends on the direction in Fix solution.

it is created by convective effect.

down in FIX solutions

disappeared when swing emulsion in FIX. (or circulation).

Reticulation on emulsion surface.

5mm

these pictures show surface of emulsion developed by usual recipe.

such non-uniformity is clearly bad.

and this make the wettability high, bad for drying.

these roughness was caused by STOP solution, especially with hardener Al2(SO4)3.

Disappeared by removing hardener in STOP.

Bubble distortion

9mm

Air bubbles in wash

water

this is veryveryvery heavy air bubbles. usually the size is <~ 0.1mm.

10mm

Use degassed water (not only wash)

Side view

less water circulation in this area.

bubble

emulsion

Glycerin non-uniformity.

Averaged in 300 micron

glycerin non-uniformity• To remove this non-uniformity

– alcohol+glycerin solution glycerin solution.– no use of drywell– remove glycerin solution completely by surface

tension before drying.

Glycerin solution

Distortion map after whole care...But

averaged in 200micron square.

mean x = -4.2mrad

x = 1.8mrad

mean y = -0.7mrad

y = 1.8mrad

Global distortion remained!

Distortion map after whole care.

stage X

stage Y

scanned 1.3mm x 1mm x 99point

on the stage

Rotate plate on the stage.

stag

e X

stag

e Y

on the stage

Global distortion looks correlated to how the emulsion sheet placed on the stage

origin of global distortion correlated to the stage.

z-axis stagger CCD

CCD camera move

we must develop blade spring type Z-drive (future plan)

Distortion on one plate.

x=1.5mrad y=1.6mrad

scanned 1mm x 1.3mm x 99point

believe only angle y (stage coordinate) and plot

Distortion map after correction

x = 1.8mrad

y = 1.8mrad

measurement err~1.2mrad

averaged in 200mm square.

(~=24tracks)

9mm

averaged in 200micron square.

But, the other side.• the distortion plotted before is only objective lens side.

Stage side distortion is still remained.

Develop a way to make emulsion itself hard.

or the other way.

Summary • Distortion is removed intrinsically.

– at the level of < 2mrad.

– Now observed distortion is dominated by the stage accuracy and measurement.

Future plan•About distortion

–Packing solution & mechanical stress.–a high precision stage must be developed to go further. –the way to make emulsion hard must be developed.

•About whole CS–sensitivity of high humidity pack–Aging–BG estimation