[3DEM] A question about ice thickness of cryo-EM
Paul Chipman
paulrc at bilbo.bio.purdue.edu
Fri Feb 18 05:14:39 PST 2005
Hi Goubin,
We are using a 300kV unit when imaging through the 800nm thick ice.
As for 100kV, I really don't know how thick of ice you can image
through but as Bill pointed out, it is also a question of how well
you actually want to resolve the sample you are examining.
cheers,
Paul
At 1:16 PM -0600 2/17/05, Hu, Guobin wrote:
>Dear Dr. Bill Tivol,
>
>You are so right that the maximum ice thickness for imaging depends
>on the HT of the scope. I sent a message to Paul asking about the
>specific HT of 100 Kv. Hopefully He would tell me a number. Of
>course, I'd be happier if our colleagues could tell me the numbers
>not only of 100 Kv, but also of 200 Kv, 300 Kv and 400 Kv.
>Thanks!
>
>Regards,
>Guobin
>
>
>
>
>-----Original Message-----
>From: owner-3dem at ncmir.ucsd.edu [mailto:owner-3dem at ncmir.ucsd.edu]
>On Behalf Of Bill Tivol
>Sent: Thursday, February 17, 2005 1:01 PM
>To: 3dem at ucsd.edu
>Subject: Re: [3DEM] A question about ice thickness of cryo-EM
>
>
>On Feb 17, 2005, at 9:34 AM, Hu, Guobin wrote:
>
>
>Thanks for your information! You might have given me a basic idea
>what the maximum of ice thickness could be. Actually as indicated
>in my earliest message, I'm not trying to figure out how thick the
>ice could be in any specific case. What I'm trying to find out is an
>estimate of the maximum of ice thickness of cryo-EM grids which is
>good enough for imaging. I wonder if anybody has ever collected data
>with ice thicker than 800 nm.
>
>
>Thanks for any further help!
>
>
>
>Dear Guobin,
>The maximum ice thickness for imaging depends on the HT of your
>scope. We have been imaging small whole cells at 300 kV, and we can
>do tomography on cells that are a little smaller than 1 um. Of
>course, the ice may not be that thick except in the immediate
>neighborhood of the cell, and the resolution should improve for
>thinner ice, so the answer to "Is the ice too thick for imaging?" is
>"It depends on what you're trying to do and what equipment you have
>to do it."
>Yours,
>Bill Tivol, PhD
>EM Scientist and Manager
>Cryo-Electron Microscopy Facility
>Broad Center, Mail Code 114-96
>California Institute of Technology
>Pasadena CA 91125
>(626) 395-8833
>tivol at caltech.edu
>
--
Paul Chipman
Electron Microscopy Facility Manager
Dept. of Biology, Purdue University
Lilly Hall, Rm. B216
Phone: 765-494-1487
Fax:765-496-1189
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