Hello all, I'm an undergraduate at a large research university in Massachusetts working in a lab where my group contributes to the Muon g-2 experiment at Fermilab in chicago. Essentially what I'm working on is optimizing an optical rotation (Faraday) magnetometer system for use in magnetic field calculations of timescales on the order microseconds (particle decay) and had a few general questions I was hoping some of you might be able to help me with. To make all this short (something antithetical to my nature so please bear with me) I have a system; the magnetometer (an SF-59 crystal rod with a solenoid wrapped around it and a function generator attatched to generate a B field which has a 1mW ~406nm laser passing through the central axis of the rod and into a 90 degree beamsplitter which bifurcates the beam at a right angle and distributes it into two photodetectors). The photodetectors are wired up in a subtractor circuit (the intent and result of which is to subtract away the common background noise experienced by both photodetectors. The circuit is encased in a metal box which is intended on shielding the circuit from ambient electronic noise. The circuit is wired to a DAQ assist data collection box and fed into LabView where I can analyze the voltage and fourier transform it to determine the strength of our signal versus the noise. The objective is to reduce the noise we see at 60 Hz as much as possible in order to see a minute signal at the actual project. Given that exposition I was wondering a few things; I have an idea of how electrical noise is generated and enters a system but was seeking validation, clarification or correction in my understanding. Household electronics are powered by electrical currents (typically AC currents -- which oscillate at a particular frequency, say 60 Hz) as a result of the flow of charge photons are radiated away with frequencies corresponding to the number of oscillations a second of the current. For instance the lightbulbs operate at 120 Hz and as a result anytime I take data with the lights on I get an enormous spike at 120 Hz in my power spectrum). Now I understand the generation of noise (I think!) but exactly how it seeps into a system im not as clear on. I imagine the photon gets absorbed by some portion of the system (say the laser beam or the actual circuit (through inductance of the resistor?) or the cables leading from the circuit to the data acquisition terminal) and then contributes that frequency component to the overall electrical signal as its transduced back into electrical current. Any clarification or further understanding (as there always is) is much appreciated. I need to know the origin and process behind the noise before I can think through how to effectively eliminate it. In addition to that general question, being that my project emphasizes 60 Hz noise (as that's the frequency our signal will be at) I was wondering if there were any standard conventions for eliminating 60 Hz noise or more broadly speaking if there are conventions for eliminating noise of any arbitrary frequency? Furthermore does anyone know of any common sources of 60 Hz noise that might nudge me in the right direction on my investigation? As I mentioned the 120 Hz noise coming from the room lights previously I imagine there are some common appliances which put out noise at 60 Hz as well -- perhaps computers? Monitors? Cellphones? Etc... I thank anyone who was willing to read through my entire message. I would appreciate as prompt a message as possible (as I need to address this issue again tomorrow at noon) so i encourage anyone who wants to reply to any portion of my message (the general question about understanding noise, the conventions question or listing any possible sources) to please do so without feeling obligated to respond to everything I've posted, a response to any part of my questions will be greeted with appreciation and gratitude. Thanks to anyone willing to help a frustrated undergrad out!