Hamburg - Opera Collaboration Meeting - June 2004 Fiducials & labels F.Laudisio,G.Romano,C.Sirignano Salerno Emulsion Group

Since we will have  bricks and 57 plates per brick we will need (18+6) digits, then a parity check on 0-1. This grid wouldl be also used for CS films and they will undergo the same brick plates’ gridding procedure.  50 to 100  m Introduction One or two lines

Set-up We studied how to realise the image and transfer it to the emulsion film. We tryed two possible solutions: 1) Optical fibers + LCD dispaly Light source Thick optical fiber (3-6 mm) LCD 128 x 128 They could be also in front of LCD working as a reflector Optical conduit Emulsion Lense Liquid chrystals display

2) High luminosity LEDs + lenses “... Take a LEDs’ picture on the emulsion...”

The solution adopted now is the following: PC Parallel port Software IC LEDs The IC we use is a LED display driver (M5450) and the serial data transfer from the data source to the display driver is accomplished with two signals, serial data and clock. One IC can control up to 33 LEDs. We have realised by ourselves a dedicated software for the data flow and a test-circuit of 24 LEDs. in details...

Control module Input Output

IC-M5450 IC-NE555: To regulate exposure times Trimmers: To regulate LED brightness

LEDs module LED diameter is 3mm Diffusor lense + 1mm holes on each LED

There have been ralised two tubes sliding one ino the other to focus our image on the glass top surface

Objective We used a standard 50x objective from a Canon camera.

Users’ interface Whith this simple interface it is possible to enlight the right LEDs. It is possible to increase automatically the sheet number (from 1 to 57) or to have a test image. 21

Exposure time Thanks to an array of kW resistors, one commutator and two different capacitors, we can set exposure time authomatically and we have been able to evaluate emulsion sensitivity. It turned out that working with a separate power supply of 5V a 1s exposure will be enough to have round dark dots (75  m diameter). In order to measure LEDs’ brightness one by one we used a photo-resistor and we set the proper resistence value for each LED using trimmers.

Brick & Sheet Id Then we performed a test exposure with Brick number fixed and Sheet number raising from 1 to 57. We have chosen two exposure times ( 0,5 s and 3,3 s). Results looks like really promising... 3,3 s 0,5 s

Gridding We can realise a reference grid of 3 or 4 single dark dots with separate tubes and objectives fixed under the table. Reference corner It will be possible to authomathize gridding procedure using a robot similar to the BAM’s piling machine, it will give us a reasonable gridding precision.