1 A status report A procedure for ensuring

1 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 D 0. 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 will be undertaken at a speed that will allow the QA procedures to be optimised. Quality Assurance for Sci. Fi Tracker (Brunel, FNAL, IC, Osaka) Tracker QA P. Kyberd, M. Takahashi

Fibres arrive their properties having been measured at FNAL and Osaka (Transmission tests for clear fibres and property measurements for scifi using coupons) 2 Clear fibres run from several station connectors. (internal clear fibres) Fibres run from the doublet layer 20 or 22 bundles are bought into a station connector Patch Panel are collected into bundles of 7 fibres External clear fibres Problem: As soon as the fibres are glued into the connectors no further corrections to errors, omissions or faults is possible Tracker QA Connector to the VLPC cassettes P. Kyberd, M. Takahashi

Possible Faults: Bundles may have too many or two few fibres 3 Fibres incorrectly positioned in connector QA Gauge Misalignment between connectors Clear fibres incorrectly positioned in connector Or fibres may be crossed over Objective: Identify faults before it is too late to correct them OR reject the component before too much time has been spent on it. Make visual records (photos/videos) at every step Tracker QA Patch Panel External clear fibres All fibres susceptible to cracking leading to unacceptable light loss P. Kyberd, M. Takahashi

4 Station Assembly and QA (details of the station assembly given at the tracker parallel session) Doublet layers arrive from FNAL (sample fibres packed with the doublets to act as “telltales”) Perform QA at each step of the assembly procedure • comb to hold bundles check bundling and sequence • connectorisation bridge to hold the connectors check bundle position before potting OLD Assembly Setup: Carbon-fibre station holder NEW Bundling Comb - QA Connectorisation bridge - QA Vacuum chuck Change of comb design after the last CM Alignment jig Tracker QA P. Kyberd, M. Takahashi

5 1 station connector worth of bundles (7 fibres) held together with rubber sleeve, placed in grooves Count # of fibres under yellow light • fibres visible by eye – important to keep the fibre ends aligned Check bundling: Tracker QA • one photo per column (11 bundles) or two columns (one connector) P. Kyberd, M. Takahashi

6 Fibre bundles Can measure < 5% of the nominal output Light leak Cameras Light source comb (illuminate single fibre or a bundle of fibres) Mirroring of the fibres prevents injection into the rear of the plane Setup for the final scan for bundling: Identify crossover fibres Tracker QA (check again later with the new doublet layers for station 5) Illuminating the plane will also allow measurement of the light loss from the mirrored end of the fibres P. Kyberd, M. Takahashi

7 potted, cut & polished held in rubber sleeve (370 nm LED) Will be using a micro-positioning table (brought in from Brunel) for a fully automated scanning system Scan over the doublet layer using LED • • Test Scan: Tracker QA Need to determine which LED (wavelength, intensity, collimation…) also depends on the UV damage on Sci. Fi (later in the talk) Optimise CCD (focal length, exposure, comb coverage…) Ideal to illuminate single fibre to identify any crossover but very difficult especially for the bottom layer (movie taken with 400 nm LED on next slide) We may consider illuminating one bundle at a time P. Kyberd, M. Takahashi

8 LED 6 7 2 4 5 3 1 4 52 7 6 1 3 Single Fibre Scan Tracker QA First attempt to illuminate single fibre… (400 nm LED) P. Kyberd, M. Takahashi

9 Fibre bundles Camera connectors on bridge Light source Sideview Scan after placing bundles in connectors • Check bundle sequence before potting • Optimum design of bridge will be determined Tracker QA LED Suitable bend radius P. Kyberd, M. Takahashi

10 Scan film Tracker QA Prototype station: demonstration of incorrect bundle position identify these faults before potting P. Kyberd, M. Takahashi

11 UV light damages the scintillation fibre – need to minimise damage and quantify the dangers. Wavelength Currently using 370 nm & 400 nm LEDs to test QA methods. D 0 have used longer wavelengths MICE have ordered longer wavelength LEDs and we will use the longest wavelength which gives satisfactory results. D 0 also pulse their UV LEDs and we will implement this if it is necessary Test measure the damage and set a limit of 1/10 of a photoelectron for the maximum damage make sure the total illumination for normal checking is less than 1/5 of this dose UV damage Tracker QA P. Kyberd, M. Takahashi

12 Hitachi U 4100 sample compartment at Brunel Detectors & integrating sphere Measure effect of UV irradiation on the fibres (single or a bundle). Using high performance photometer Aperture High precision fibre launcher Compartment modified to take optical rails and other components Status: • Purchased narrow pass filter to absorb scintillation light • Measurements starting presently • A couple of % measurement possible now and <1% later with optimisation • The same setup will be used to check the “telltales” arriving from FNAL with doublets Tracker QA P. Kyberd, M. Takahashi

Clear Fibre Waveguides 13 Fibre runs: Manufacturer puts the connectors and check the fibre runs will be checked again at Osaka • Injection of LED light done by hand from one end and visual inspection on the other end (video) • Misplacement of fibres can be corrected in the analysis Bad Channels: A number of methods exist to identify bad channels (following slides) Tracker QA P. Kyberd, M. Takahashi

14 Methods for finding bad channels (presented by Osaka at pc 191) • 2 kinds of method are applied. Method (1): Taking pictures by a digital camera with flash from the surface of D 0 connector ( or Inner connector). Some bad channels seems shining, which are considered as a reflecting light from bad surface inside the fiber. Method (2): Looking fibers by eye with injecting light from the connector and finding bad fibers where light is leaking. • And confirming that bad channels found at (1) and (2) are same or not. (1) Reflecting light Tracker QA (2) Leaking light P. Kyberd, M. Takahashi

15 Transmission Test (presented by Osaka at pc 197) Black Box ～ 20 cm Diffuser D 0 connector Rolled Green LED MICE ND filter connector Digital camera Old-type waveguide DC Power Supply Tracker QA P. Kyberd, M. Takahashi

16 Measured luminosity (presented by Osaka at pc 197) • Right picture shows that channels of small amount of luminosity corresponds to those found by reflecting light check. • Converting Raw data into ascii file in order to estimate quantitatively. (not yet finished) Transmission test #1 Reflecting light check #1 #2 #4 #5 #3 #7 #4 #5 #6 Tracker QA #7 #8 #9 #10 #6 #10 P. Kyberd, M. Takahashi

17 Station Acceptance Test Assembled stations will then be irradiated for a final check • Co-57 as a radiation source (122 ke. V photons) on XY scanning table • Full readout chain (VLPC, AFEs) Measurements will be made on station 4 first compare with testbeam results for validation to VLPC to stage controller garage position station holder patch panel XY stage Light tight box Tracker QA P. Kyberd, M. Takahashi

18 Tracker QA Time Line P. Kyberd, M. Takahashi

19 100% correct fibre runs Light loss from all sources : bend, cracking, misalignment : < 10%. Light yield measurements good to better than 10% Systems will be ready for assembling and testing of the 5 th station when the first doublet layers arrive (mid-August). Steady construction of a station 5 to validate the system. By end-September the validated QA system will be in place. Ready to start production. Once the planes have been constructed they will be geometrically characterised with a CMM. Summary : Tracker QA P. Kyberd, M. Takahashi