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Introduction Preparation of Items by JasonDetriou


                          BY LOUIS EZENABO
                          Summer RET Program
                          Wayne State University

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.

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

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