Changeable Sheet A.Ariga, Nagoya univ

CS strategy R&D~2004-Oct –BG rejection Distortiondistortion itself, precise measurement, packing Self-Refreshparameter study –Aging test at high humidity sensitivity, fog, etc. CS packing machine development ~2004-May Production2005-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. N BG ∝ (θ allowance ) 4  Distortion Study θ allowance 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 –~10 5 particle / cm 2 low humidity packed

Stripe shape Distortion 4mm

Distortion by Stripe of emulsion surface. Position X  x =  Microtrack -  Basetrack 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 Al 2 (SO 4 ) 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. stage X stage 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 200 m m 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