[3dem] [External] Re: plasma cleaner question
David Michael Belnap
David.Belnap at utah.edu
Fri Feb 16 09:21:09 PST 2024
To backup Ilya’s message, I use a “homemade” glow discharger that is attached to an oil vacuum pump. Many years ago, we saw spots all over our cryo-grids and wondered where the spots were from. We suspected that oil vapor from the pump might be the problem. When we moved the vacuum pump into a chemical hood and had a long enough hose to connect to the glow-discharge chamber on the bench, the spots on the grids disappeared. The vacuum pump has remained in the hood ever since.
If anyone is interested in building their own “homemade” glow discharger, contact me. I’d be happy to share my plans.
David
From: 3dem <3dem-bounces at ncmir.ucsd.edu> on behalf of "Ilya R." <ireviakine at gmail.com>
Date: Thursday, February 15, 2024 at 4:09 AM
To: Sylvain Trepout <sylvain.trepout at monash.edu>
Cc: "3dem at ncmir.ucsd.edu" <3dem at ncmir.ucsd.edu>
Subject: Re: [3dem] [External] Re: plasma cleaner question
Dear David,
Like the others have already said, there is no problem with the plasma cleaners' pump exhaust venting directly into the lab. In the old days, the problem was more the oil fumes from the oil pumps - those required handling of the exhaust. I presume that nowadays you have an oil-free pump. What vents into the atmosphere is the exhaust of the pump, not from the plasma cleaner itself, and there are no high-energy ions in the pump exhaust any more: a low enough pressure is required to create the plasma. You can actually demonstrate this to your colleague by turning on the coils and watching the glow: it will appear only when the pressure is low enough.
This is different from the UVOzone cleaners, which release significant amounts of ozone and require proper exhaust handling.
Good luck. :)
Ilya.
On Thu, Feb 15, 2024 at 4:51 AM Sylvain Trepout <sylvain.trepout at monash.edu<mailto:sylvain.trepout at monash.edu>> wrote:
Hi David,
This might be your solution story.
During plasma cleaning, the pump is on. Meaning that the plasma is being sucked-up by the pump.
Since the pump is equipped with a small filter, there is no plasma released by the glow-discharger.
And you might also want to tell your colleague that venting goes the other way around, that is air from the room that goes inside the glow-discharger, not the opposite.
Cheers,
Sylvain
PhD
Research Fellow - Microscopy Australia
Monash University
Ramaciotti Centre for Cryo-EM
G92, 15 Innovation Walk, Clayton Campus
Victoria, 3800 Australia
E: sylvain.trepout at monash.edu<mailto:sylvain.trepout at monash.edu>
On Thu, 15 Feb 2024 at 14:37, Morgan, David Gene <dagmorga at indiana.edu<mailto:dagmorga at indiana.edu>> wrote:
Ruben,
That's my thought also, but one of the staff members seems to think that it will vent "plasma" into the lab. I've tried to convince her that's not a thing and that what does get vented isn't a problem, but to no avail. So I was hoping to show her that I'm not the only person who believes this...
Wish me luck :-)
--
politics is more difficult than physics.
A. Einstein
David Gene Morgan
Electron Microscopy Center
047E Simon Hall
IU Bloomington
812 856 1457 (office)
812 856 3221 (3200)
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________________________________
From: Ruben Diaz Avalos <rdiaz at lji.org<mailto:rdiaz at lji.org>>
Sent: Wednesday, February 14, 2024 10:22 PM
To: Morgan, David Gene <dagmorga at indiana.edu<mailto:dagmorga at indiana.edu>>
Cc: 3dem at ncmir.ucsd.edu<mailto:3dem at ncmir.ucsd.edu> <3dem at ncmir.ucsd.edu<mailto:3dem at ncmir.ucsd.edu>>
Subject: [External] Re: [3dem] plasma cleaner question
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Hi David,
We have also a Fischione plasma cleaner, to which we have connected a Nitrogen and an Argon tank. The instrument vents to the lab and EH & S has no problem with that. I don't think the process of plasma cleaning would produce any noxious gases anyway.
Ruben.
On Wed, Feb 14, 2024 at 12:48 PM Morgan, David Gene <dagmorga at indiana.edu<mailto:dagmorga at indiana.edu>> wrote:
Hi,
This is for any of you who have a plasma cleaner. What have you done about venting the "exhaust gases" from the device?
We are moving our Fischione plasma cleaner into a new area sample prep area. In the old location, we were able to connect the exit port of the cleaner directly into the exhaust snorkel where a fume hood was once connected. In our new location, that will either be impossible or will require a connection that spans many meters and passes through multiple walls.
I am wondering how necessary people think it is to vent directly into some sort of building exhaust system. Any thoughts?
As always, thanks in advance for your comments and ideas.
--
politics is more difficult than physics.
A. Einstein
David Gene Morgan
Electron Microscopy Center
047E Simon Hall
IU Bloomington
812 856 1457 (office)
812 856 3221 (3200)
https://urldefense.com/v3/__http://iubemcenter.indiana.edu__;!!Mih3wA!ETcUVGhf48_5fyuF76JjkeQq1oob8tYb_SXLE27nej2ZXmauzjVerEUU3eYmSFb9lMbB9jd-9up1adAERpQzCwmVMHw$ <https://urldefense.com/v3/__http:/iubemcenter.indiana.edu__;!!Mih3wA!H1ezyicc3l9zqC84h5PenRpoYK2sNH9uBOXeEyt4bwThP5eeNk7_JR3tAVW05iBVg0yKt09vOIXBlbiajjOxOUA$>
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