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Hi Tyler,</div>
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Thanks a lot for the study, we had a discussion with our German collaborators about it and they had a similar feeling that we should be fine with cutting it out as a background. Having said that I think it is now way brighter than 58 Lumins that are required.</div>
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Cheers,</div>
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<br>
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Greg<br>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> dsg-eic_dirc <dsg-eic_dirc-bounces@jlab.org> on behalf of Tyler Lemon via dsg-eic_dirc <dsg-eic_dirc@jlab.org><br>
<b>Sent:</b> Thursday, September 28, 2023 4:02 PM<br>
<b>To:</b> dsg-eic_dirc@jlab.org <dsg-eic_dirc@jlab.org><br>
<b>Subject:</b> [dsg-eic_dirc] EIC DIRC Exit light study</font>
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Hi Beni and Greg,</div>
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Since Monday's meeting, I have been thinking of ways to help us resolve the exit light problem.</div>
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In the meeting, you mentioned that we can't treat the exit light like a background light noise and subtract it from measurements because the light is AC powered.</div>
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After thinking more on this and about the exit light's behavior when you press it's test button, I started to think that this is not true, so I did a few tests.</div>
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The results of these tests are covered in the attached PowerPoint since I wanted to be able to explain my thought process and thought slides would be a better format.</div>
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A brief, three sentence summary is:</div>
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I set up one of the test station photodiodes with a 10-kŮ resistor in series, pointed the photodiode at the red LEDs through the sign's lettering, and observed the response of the photodiode by measuring the voltage drop across the resistor.</div>
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No changes in the voltage were seen for the red light from the EXIT sign.</div>
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With this, I think that the red light from the exit sign can be treated as a background noise and subtracted off of any measurement.<br>
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Since it is a lot of info, we can discuss it more in Monday's DSG - EIC DIRC meeting.
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-Tyler<br>
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