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2007 RESEARCH EXPERIENCE FOR TEACHERS REPORT BY LOUIS EZENABO Summer RET Program Wayne State University Introduction This year’s research is a continuation of the work I did during the previous year. It involved among other things measuring scintillators, painting scintillators and measuring fibre wire. This year’s research focused on preparing the various items used in building an EMcal module. There were two phases to this research: I Preparation of items II Test and Comparison Preparation of Items Fiber wire Fibers of length 1.7m were cut into 40cm long segments. The cut fibres were placed inside a semi-rigid plastic compound using a special technique. The semi-rigid plastic compound was molded round outside and hexagonal inside. The fibers were placed inside the plastic using a special technique. About 313 40 cm long fibers were squeezed inside the plastic. The wires were then placed in small quantities, about 10 each time, and as more wires wre placed, the number placed each time was reduced. This allowed a one- way traffic direction while placing the wires inside the plastic. The wires are only pushed downwards, the reason being to assure same level at the top and bottom (where the cap is placed) of all wires placed inside the plastic. It also helps during final cutting and polishing of the wires. The fibers were then bundled and placed inside a glass/jar of water. The bundles were allowed to soak for about five minutes. The fibers were then removed from the water and placed in a refrigerator. They were frozen to –30C or –25F for a period of 20 hours. The frozen fibers were dipped inside nitrogen compound at a temp of –169C for about five minutes. At this point, the water between the fibers becomes hot. This helps to keep the fibers firm while cutting which in turn allows for a neat cutting and polishing at both ends of the fiber. The now frozen fibers were then clipped on a machine for cutting. Three levels of cutting were made using three drivers. The first cut was made with short carbon driver, the second with long carbon driver and the third with a diamond driver. The diamond driver cuts at 25 microns, this third cutting is referred to as polishing. Fibers were then left to defreeze. They were put in a mixture of water and alcohol. After they were removed and dry then they are ready for testing and use in building modules. Aluminum and 0.75mm wire cutting The next step was the cutting of aluminum pipes. Two sets of different size aluminum pipes were cut. The first 16 set of size 1/16in was cut at 15mm long. The second 16 sets of size 3/32in was also cut at 20mm long. Next a 0.75mm wire manufactured by ‘TORAY’ was cut at 1.4m long; one end of this wire is stripped of plastic covering at about 5.2mm long. About 16 piece of this wire were cut to equate the 16 pieces of the aluminum pipe. A mixture of glue was prepared. The glue was prepared with 1.5g of rasin to 0.47g of hardnesis/hardner. The smaller size aluminum pipe was glued to the wire at a small section where the naked and covered part of the wire meet, then the bigger size aluminum pipe was also glue to the tail of the small aluminum pipe. These were tapped to the preparation desk so that the glued part does not shift as the glue dried. Test and Comparison Different institutions are concurrently building EMcal modules. Some of these institutions are overseas. In order, to test for uniformity, we had to check for differences and uniformity in the various modules that were being built at the different manufacturing locations. Consequently, random selections of fibre wires were made from USA and from Italy. The wires were tested for light emittance at two inches apart. The results of the test are forthcoming. Conclusion Bringing it together, modules are built with fiber wires. Each module has four channels. A bundle of twelve modules become a strip of module. Each of the twelve modules are connected at the channels through a 0.75mm fibers. This fiber is further connected to 3mm fibers which is then connected to a Light Emitted Diode (LED). LED generate short light signal. This signal is transferred to the modules through the 3mm and 0.75mm wires.
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