The Ludlum Project Advisors: Dr. Randal Ruchti, Dr. Dan Karmgard Mark Vigneault Teacher: Mark Kirzeder Students: Kristen Anderson Mengwen Zhang

History of Notre Dame  Ongoing  Ludlum Measurements Inc.  In the past, separate wave shifting and scintillating materials were used in combination with one another.

 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 ND

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.

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

Test – Scintillation  Used to test all three factors

Experiment Set Up within a light tight box Sr 90 Fiber PMT Counter Paddles Brass plate Apiazon Radioactive source Data PMT

Experiment Set Up Optical fiber Bronze plate Radioactive source Time- gate paddles

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

Data Gathering

Calculating Brightness  Brightness is a measure of how much light the fiber transmits  Integration yields total light Several integrations completed

Calculating Brightness Average brightness is 1021 units at 1.5 m.

Calculating Decay Time  Used for comparative analysis.  90% - 10% of curve used  A best fit exponential or semi-log plot  2.93m magic number

Calculating Decay Time

Decay time = 1 / c =18.35ns

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

Calculating Attenuation Length Attenuation Length = 1 / c =4.96m

Test – LED Attenuation  A new test  UV LED’s 395nm and 405nm Quicker Easier

Test – LED Attenuation  Failures Inconsistent data Unexpected results  Success Development of sound data analysis techniques Improvement of experimental techniques

Experimental Set Up within a light tight box Sr 90 Fiber Apilazon LED Photo Diode

Experimental Set Up Fiber LED Photo Diode

Calculating Attenuation Length Attenuation Length = 1/c = 3.00m

Calculating Attenuation Length Attenuation Length = 1/c = 4.74m

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