Tracker QA Paul Kyberd Quality Assurance A status report: A procedure for ensuring the quality of the finished tracker has been designed following our experience with the construction of the prototype and advice from D0. The various components of the system have been individually validated, or the problems identified and we have confirmed that suitable solutions exist. A plan exists to provide a working system in time for the delivery of the fibre doublets and the construction of a fifth station. The construction of the fifth station is being undertaken at a speed that will allow the QA procedures to be optimised. The final procedure will have been defined by the collaboration meeting at RAL

Tracker QA Paul Kyberd are collected into bundles of seven Fibres run from the doublet layer 20 or 21 bundles are bought into a station connector Clear fibres run from several station connectors to Connector to the VLPC cassettes Problem: As soon as the fibres are glued into the connectors no further corrections to errors,omissions or faults is possible

Tracker QA Paul Kyberd Bundles may have too many or two few fibres Fibres incorrectly positioned in connector Incorrect positioning of the fibres to the VLPC not part of tracker QA Possible Faults: Or fibres may be crossed over Misalignment between connectors Clear fibres incorrectly positioned in connector Misalignment between connectors All fibres susceptible to cracking leading to unacceptable light loss

Tracker QA Paul Kyberd Objective: Identify faults before it is too late to correct them OR reject the component before too much time has been spent on it. Method: Inject light.and track its path Silvering of the fibres prevents straightforward injection into the rear of the plane Solution illuminate the plane with a UV LED Picture of fibre fluorescing Picture of illumination system Question of damage to the scintillator (considered later)

Tracker QA Paul Kyberd Picture of scanning system

Tracker QA Paul Kyberd Bundle fibres up into sevens – do about 10 bundles. Illuminate Picture of comb Hold the fibres together with a rubber sleeve (already used to make the prototype. Place the bundles in a “comb” to hold them together and in place For these pictures 370nm was used throughout

Tracker QA Paul Kyberd Bundle fibres up into sevens – do about 10 bundles. Illuminate Clearly observe the two Layers Counting seven is easy Unfibre and repeat if problems Number determined by experiment – to minimise the total construction time. it takes n minutes to make a bundle we check every G bundles which takes a time of (G*m + s) minutes. If the probability of making a mistake is p% (known empirically to be <1%). Total time for a plane is ~ [G*n + (G*m + s) + p*(G+1)*n/2]*T/G with T bundles per plane.

Tracker QA Paul Kyberd A B Circle radius of 12 pixels used, Integral intensity in arbitrary units. Background “black” is effectively 0 Automatic Measurement: An astronomical program confirmed we can identify individual fibres we can measure their light output In this picture no attempt was made to control the illumination

Tracker QA Paul Kyberd Final scan: Final scan to check Second camera is looking at rear of fibres for excessive light leaks. Can measure < 5% of the nominal output

Tracker QA Paul Kyberd Scan after placing bundles in connectors Frame mounted to take connectors and bundles placed in the correct place in each connector Scan across the full plane to check that bundles are correctly placed in connectors Does Geoff have an drawings of this?

Tracker QA Paul Kyberd Status: All fibres in their correct bundle All bundles in their correct station connector Ideally we would also check light out put at this stage but until the fibres are glued into the connectors and the ends polished a reliable measurement of the light output is not possible Silvering OK

Tracker QA Paul Kyberd Light Output: Picture of glued and polished system At this`stage we measure light output. We will also make this measurement on the old stations which have been disassembled – this will allow us to validate the UV measurements against the test beam results

Tracker QA Paul Kyberd Check “wiring” of clear fibre runs Picture of clear fibre bundles and the connectors at each end Inject red light and measure output fibre. Injection done in order by hand – photographs taken of the output and the two cross correlated subsequently. The experimenter will record the input connector/fibre number, the programme will determine the “correct” input connector/fibre number from the output fibre number. The experimenter will not be able to influence the comparison in order to combat the “see what you expect” effect

Tracker QA Paul Kyberd Final check Connect up final station and scan checking light output at the end of the clear fibre run This is a final cross check and is not strictly necessary. Given that the fibres of the two other views will also receive a UV dose this measurement will only be made if the safety margin on the damage is significant.

Tracker QA Paul Kyberd Charged particle tests The station will then be irradiated by a …. Source to check response to charged particles. Any variation of light output observed at this stage can be referred back to the UV measurements and the discriminating power of the method determined. Ken - do you want this covered in QA?– if so do we have any drawings/pictures or other information which should be included. These measurements will also made on existing stations and the test beam results used to validate the measurements.

Tracker QA Paul Kyberd Wavelength Currently using 370nm LEDs which give good results. D0 have used longer wavelengths MICE have ordered longer wavelength LEDs and we will use the longest wavelength which gives satisfactory results. D0 also pulse their UV LEDs and UV damage UV light damages the scintillation fibre – need to minimise damage and quantify the dangers. Test measure the damage and set a limit of 1/10 of a photo- electron for the maximum damage make sure the total illumination for normal checking is less than 1/5 of this dose

Tracker QA Paul Kyberd Compartment modified to take optical rails and other components Aperture Detectors & integrating sphere Hitachi U4100 sample compartment Measure effect of UV irradiation on the fibres.

Tracker QA Paul Kyberd High precision fibre launcher Light injection

Tracker QA Paul Kyberd April 24 - May5Determine UV wavelength May 1 –May11Measure UV damage for 3 wavelengths 1 st Week JuneShip scanning table to IC from Brunel ????Delivery of comb from Liverpool ????Fibre table ready (including connector holders) ????Ship old plane from Brunel (same as comb delivery) ????Check of fibre procedure April 24 – June 26Complete test rig software June 26 – July 7Assemble the old plane and verify the procedure

Tracker QA Paul Kyberd System to be ready by end June for the delivery of the first doublet layers. Slow construction of a plane to shake down the system and sort out any problems. By the September collaboration meeting - the final QA system will be in place. Ready to start production April 24 - May5Determine UV wavelength May 1 –May11Measure UV damage for 3 wavelengths 1 st Week JuneShip scanning table to IC from Brunel ????Delivery of comb from Liverpool ????Fibring table ready