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Published byTrevor Reynolds Modified over 8 years ago
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The Ludlum Project Advisors: Dr. Randal Ruchti, Dr. Dan Karmgard Mark Vigneault Teacher: Mark Kirzeder Students: Kristen Anderson Mengwen Zhang
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History of Ludlum @ Notre Dame Ongoing Ludlum Measurements Inc. In the past, separate wave shifting and scintillating materials were used in combination with one another.
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Current experiments are focused on materials that are manufactured with both properties in a single fiber. Old 3HF New 3HF OX-550F 4CN-HBT Current Focus of Ludlum @ ND
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Current Goals of Ludlum The goal of the project is to find a material that can be used in new particle detectors. Several methods have been developed in the past and are in use at FermiLab and CERN currently.
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Factors Tested This Summer Brightness How much light is transmitted along the fiber Decay Time How much time passes between excitation and relaxation of molecules in the fiber Attenuation Length How long can a fiber be before light begins to escape
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Test – Scintillation Used to test all three factors
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Experiment Set Up within a light tight box Sr 90 Fiber PMT Counter Paddles Brass plate Apiazon Radioactive source Data PMT
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Experiment Set Up Optical fiber Bronze plate Radioactive source Time- gate paddles
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Data Gathering Two paddles are used as triggers Brass plate shields Radioactive source Data is stored on an oscilloscope 2048 data points per run - averaged 6 or more runs per graph - averaged Several distances from source to PMT
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Data Gathering
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Calculating Brightness Brightness is a measure of how much light the fiber transmits Integration yields total light Several integrations completed
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Calculating Brightness Average brightness is 1021 units at 1.5 m.
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Calculating Decay Time Used for comparative analysis. 90% - 10% of curve used A best fit exponential or semi-log plot 2.93m magic number
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Calculating Decay Time
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Decay time = 1 / c =18.35ns
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Calculating Attenuation Length L out = L in * exp (-x / Attenuation Length) Attenuation length is the distance at which 1/e of the original light remains Light out data was gathered at 1.0m, 1.5m, 2.0m, 2.5m, and 2.93m Incomplete data set
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Calculating Attenuation Length Attenuation Length = 1 / c =4.96m
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Test – LED Attenuation A new test UV LED’s 395nm and 405nm Quicker Easier
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Test – LED Attenuation Failures Inconsistent data Unexpected results Success Development of sound data analysis techniques Improvement of experimental techniques
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Experimental Set Up within a light tight box Sr 90 Fiber Apilazon LED Photo Diode
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Experimental Set Up Fiber LED Photo Diode
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Calculating Attenuation Length Attenuation Length = 1/c = 3.00m
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Calculating Attenuation Length Attenuation Length = 1/c = 4.74m
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Conclusions Preliminary results indicate New 3HF is the brightest fiber 4CN-HBT has shortest decay time 4CN-HBT has the longest attenuation length The nature of future experiments will dictate which fibers will be used There may not be one perfect fiber
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