- #1
What is causing the strange signal on my PMT R928?
Click For Summary
Discussion Overview
The discussion revolves around a participant's experience with a Hamamatsu R928 photomultiplier tube (PMT) that is producing an unusual signal when connected to an oscilloscope. Participants explore potential causes for this signal, including environmental factors and equipment setup.
Discussion Character
- Exploratory
- Technical explanation
- Debate/contested
Main Points Raised
- One participant reports a strange signal from the R928 PMT and seeks insights into its origin.
- Another participant inquires about the PMT's coverage and the type of fixture used, suggesting that a schematic could help diagnose the issue.
- A participant clarifies that the PMT is open and describes the socket assembly used for connection.
- Questions are raised about the oscilloscope settings, specifically the vertical scale and timebase, to better understand the nature of the noise observed.
- One participant suggests that the observed noise could be related to electromagnetic interference (EMI) from a nearby switch-mode power supply (SMPS).
- Another participant proposes testing the PMT's response to light sources, such as a flashlight or a TV remote control, to determine if it is functioning properly.
Areas of Agreement / Disagreement
Participants express various hypotheses regarding the source of the strange signal, with no consensus reached on the exact cause or whether the PMT may be faulty.
Contextual Notes
Participants have not fully explored the implications of the oscilloscope settings or the specific environmental conditions that might affect the PMT's performance. There are also unresolved questions about the PMT's operational status.
Who May Find This Useful
Individuals interested in photomultiplier tube operation, troubleshooting electronic equipment, or those experiencing similar issues with signal detection may find this discussion relevant.
- #2
berkeman
Admin
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Is it covered or open? What kind of fixture are you plugging it into? Can you post your schematic?
https://www.hamamatsu.com/blobs/1328784013964?blobheadername1=content-disposition&blobheadervalue1=inline%3Bfilename%3D1328467311959.jpg&ssbinary=true
https://www.hamamatsu.com/blobs/1328784013964?blobheadername1=content-disposition&blobheadervalue1=inline%3Bfilename%3D1328467311959.jpg&ssbinary=true
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- #4
jim hardy
Science Advisor
Homework Helper
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What are vertical scale and timebase on that 'scope trace ?
In other words - what do we know about your "noise" ?
120 hz would likely be nearby fluorescent lights.
In other words - what do we know about your "noise" ?
120 hz would likely be nearby fluorescent lights.
- #5
Rive
Science Advisor
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So far it looks like common EMI from an SMPS nearby.
- #6
- #7
jim hardy
Science Advisor
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what does yours look like at those people's settings?
\
shine a flashlight on it through a fan blade.
or point your TV remote control at it and press a button.
tv remote is typically just a bit longer than 900 nm so the tubewill probably see it.
.
oops make that might see it.
..
\
shine a flashlight on it through a fan blade.
or point your TV remote control at it and press a button.
tv remote is typically just a bit longer than 900 nm so the tube
.
oops make that might see it.
..
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Last edited:
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