Discussion Overview
The discussion revolves around the challenges of blocking out 100Hz electromagnetic interference (EMI) in a laboratory setting while recording transient signals from an ion source. Participants explore various methods for noise reduction, including circuit modifications, shielding techniques, and power supply considerations.
Discussion Character
- Exploratory
- Technical explanation
- Debate/contested
- Experimental/applied
Main Points Raised
- Gareth describes the issue of 100Hz EMI interfering with the detection of transient signals from an ion source, noting that the noise occurs simultaneously with the desired signal.
- Some participants suggest changing the recording frequency, but Gareth indicates this is not feasible due to the timing of the events.
- One suggestion involves using a second detector circuit to subtract noise readings from signal readings, while others propose a double correlated sampling approach.
- Participants discuss the importance of grounding and shielding, with suggestions to improve earthing schemes and add extra shielding to reduce noise.
- Gareth mentions using copper tape for shielding, which has helped but is insufficient when the power supply is connected.
- Concerns are raised about the passive nature of the circuit and whether active amplification is needed for better signal detection.
- Discussion includes the potential use of capacitors across the power supply output and threading EMI cores through leads to mitigate noise.
- Some participants express skepticism about the effectiveness of kitchen aluminum foil for shielding, emphasizing the need for reliable electrical contact and proper grounding techniques.
- There is mention of the possibility of converting the ion measuring device to battery power and using fiber optics for signal transfer to avoid noise issues.
Areas of Agreement / Disagreement
Participants express a range of views on the best methods to mitigate noise, with no consensus reached on a single effective solution. Multiple competing approaches and ideas are presented, reflecting the complexity of the problem.
Contextual Notes
Participants note that the noise characteristics vary and that the coupling mechanism of the noise (electric field, magnetic field, or conducted noise) influences the effectiveness of proposed solutions. Limitations in the current setup and the need for further experimentation are acknowledged.