[3dem] SubAngstrom Electron Dose Rate Calculator

[Michael Elbaum]

It can be useful to make an estimate in advance based on the screen current with the sample withdrawn. The current in Amperes divided by the charge of the electron (1.6 x 10^-19 Coulombs) is the flux in electrons/sec. Divide that by the field of view in Ang^2 and multiply by the exposure time to get the dose in e/Ang^2.


For semantics, "flux" describes a current crossing a surface and has units "per area per time". After multiplying by the time we're left with the dose of electrons per unit area, without the rate.


best,

Michael

________________________________
From: 3dem <3dem-bounces at ncmir.ucsd.edu> on behalf of SubAngstrom <info at subangstrom.com>
Sent: Wednesday, June 24, 2020 1:42:17 AM
To: Gabriel Lander
Cc: 3dem at ncmir.ucsd.edu
Subject: Re: [3dem] SubAngstrom Electron Dose Rate Calculator

Hi Gabe,

The physicist in me agrees wholeheartedly. If we're talking electrons, flux is proper nomenclature. We will change the name and add some other suggestions I received privately. Thanks to everyone for the feedback!

Best,
Mark

On Tue, Jun 23, 2020 at 1:14 PM Gabriel Lander <glander at gmail.com<mailto:glander at gmail.com>> wrote:
Thanks Mark!
But shouldn't this be called the "Electron Exposure Rate Calculator" or "Electron Flux Calculator"? (channeling my inner Chris Russo here...)
-gabe


On Jun 23, 2020, at 6:09 AM, SubAngstrom <info at subangstrom.com<mailto:info at subangstrom.com>> wrote:

Dear 3DEM community,

I thought it might be useful to share a link to our dose rate calculator. I use it almost on a daily basis to accurately calculate the dose based on various experimental parameters. Until recently it existed as an Excel sheet that was shared with clients and friends. I'm sure many of you use something similar while setting up your experiments, but I thought it would be nice to have easy access to it. We'll call this version 1.0 and we're happy to add any additional functionality you might find useful.

https://urldefense.com/v3/__http://www.subangstrom.com/dose__;!!Mih3wA!S7QeLfdLIZQ-PCTzbWy04Vr4uYTgpFzySBO9xYhtTikxvsNcpw_ESi5Tsv4k7VmVgQ$ <https://urldefense.com/v3/__http://www.subangstrom.com/dose__;!!Mih3wA!T7phZIi8NwgRJuPfMwThjMPmovvw1es01PaPxw0BRUsqTmMtaAHEXBMzp_ZfIQelow$>

You can send any comments or suggestions for additions to info at subangstrom.com<mailto:info at subangstrom.com>.

Happy imaging.

Best,
Mark


--
Mark Ebrahim
SubAngstrom LLC
510-303-7785
[https://urldefense.com/v3/__https://docs.google.com/uc?export=download&id=1O2ETkH4vG_vwz_lpGR89zd9UhmdGWuU0&revid=0B-fWYnHHHKGgc2pHVE9jMElxb1lFTGVzQmoyZG9VTG1DbFF3PQ__;!!Mih3wA!S7QeLfdLIZQ-PCTzbWy04Vr4uYTgpFzySBO9xYhtTikxvsNcpw_ESi5Tsv6FZwtvgg$ ]
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