Building a Straw Detector for the Muon g-2 Experiment

Octavio Escalante-Aguirre


Serving as an integral component of particle physics, the anomalous magnetic moment of an elementary particle is often used as a precision test of the widely accepted Standard Model of particle physics. While the theory successfully predicts the magnetic moment of certain particles such as the electron, recent measurements conducted at Brookhaven National Laboratory indicate that the experimental observation of a muon’s g-factor deviates from the theoretical value by 3.4 standard deviations. This unexpected outcome has caused quite a deal of excitement in the particle physics community as the divergent value suggests the possible existence of physical laws beyond the scope of the Standard Model. Seeking to confirm or debunk this possibility, Fermi National Accelerator Laboratory will run a higher precision iteration of the Muon g-2 project which will deliver the definitive experimental value of the muon’s g-factor on the order of .14ppm. In order to attain this desired level of precision the implementation of a high resolution straw-tube drift chamber will be used as the primary particle tracking source. This cutting-edge particle detector will be subject to a high vacuum environment and certain quality control procedures have been designed in an attempt to minimize the possibility of a critical failure (i.e. contamination of the regulated vacuum environment). Northern Illinois University is involved in this quality control procedure and will oversee the assembly of the straw-tube tracker modules. Creep, leak, resistivity and other tests vital to the assembly of the prototype drift chamber have already been put into action with successful results. One of these methods includes the study of a non-contact approach for measuring the tension of the Mylar straw-tubes. By vibrating the straw-tube inside of a known magnetic field with the use of a loudspeaker, the tension of the straw-tube can be approximated by the relationship of the resonant frequency and the set tension. Further collaboration between Fermilab and Northern Illinois University hopes to automate these quality control systems and implement them during the proton test beam runs in 2014.


Straw Tracker; Muon g-2; Tension Measurement

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