🚀 go-pugleaf

I am trying to optically couple a CCD camera to an electron microscope. The scope
camera port is designed for a standard 'C' mount video camera, while the CCD
camera is designed for an F-mount lens. 

I have worked with several lens vendors in an attempt to procure a lens which is
designed to mate (optically) my camera to the EM. So far to my disbelief I have
not been given a successful design.

What I need in simple terms is a very fast (f <= 1.0), demagnifying or reducing
lens. Has anyone out there had any experience with mating cameras in non-standard
situations. Could anyone recommend a consulting resource?

This has been an extremely fustrating problem and any advice or help would be
greatly appreciated.

Thanks,
Gary McCauley

In article <5808@news.duke.edu> mccau002@acpub.duke.edu (Gary McCauley) writes:
>I am trying to optically couple a CCD camera to an electron microscope.
>The scope camera port is designed for a standard 'C' mount video camera, 
>while the CCD camera is designed for an F-mount lens. 

My first reaction was to do away with the lens altogether, and put the CCD
straight into the TEM (it is a TEM isn't it?).  I'm not sure how far your
electrons would go in Si, as I used to do SEMs instead, but it ought to be
quite a bit less than the ten microns pitch of the devices.  They might also
make considerable IR, and the window of the CCD would probably have to go.

Has anyone tried this? :)

Thinks - they must have... no-one willingly electrons into light, then
light back into electrons unless they have to :(

-- 
Richard Kirk         Image Processing Group    Crosfield Electronics Ltd. U.K.
rak@crosfield.co.uk  0442-230000 x3361/3591    Hemel Hempstead, Herts, HP2 7RH

In article <15563@suns3.crosfield.co.uk>, rak@crosfield.co.uk (Richard Kirk) writes:
|> My first reaction was to do away with the lens altogether, and put the CCD
|> straight into the TEM (it is a TEM isn't it?).  I'm not sure how far your
|> electrons would go in Si, as I used to do SEMs instead, but it ought to be
|> quite a bit less than the ten microns pitch of the devices.  They might also
|> make considerable IR, and the window of the CCD would probably have to go.
|> Has anyone tried this? :)

I'd asked this of everyone I could find about a year ago and found that the
overwhelming consensus was that this was a Bad Idea.  

First, depending on the electron voltage, one could torch the CCD.  Also, 
some sort of shutter mechanism will be needed to handle exposure timing 
(one could use the beam on/off/intensity, but the change in voltage produces
a blooming that would distort), so you'll be bombarding metal with electrons,
which is also a Bad Idea for a sensitive CCD/electronics.  In addition, if 
any gold is used in the CCD (contacts, whatever), then you'll get some small
x-ray emissions to deal with as well.  Also, thermal expansion of the CCD 
could eventually be a problem.  

I don't want to be a downer on this and would actually be really excited for
someone to look into it, but I do want people to realize the implications.
I'd suggest calling some of the manufacturers of TEMs (Philips, Zeiss, JEOL)
and finding out what the details are and then contacting the CCD fabs and
asking if they can handle those kinds of conditions.  I'd really love this
to work someday...

							kevin

>|> My first reaction was to do away with the lens altogether, and put the CCD
>|> straight into the TEM (it is a TEM isn't it?).  I'm not sure how far your
>
>I'd asked this of everyone I could find about a year ago and found that the
>overwhelming consensus was that this was a Bad Idea.  
>
>I don't want to be a downer on this and would actually be really excited for
>someone to look into it, but I do want people to realize the implications.
>

[ cut, snip, cut ]

Actually we are in the process of putting a 1024X1024X24 bit camera
in our 200 KV hitachi.  You can do it two ways a camera with an
axis parallel to the beam looking down at the phosphor screen (but
there are problems with stray electrons, x-rays in the column) or,
as we are doing, using a ccd camera specifically made to fit in
the column and intersect the beam with the detector.  There is a
device of some type between the ccd and the beam, so you don't get
200 kv electrons zipping through the ccd - electrons go REAL far in
silicon and other semiconductors.  I believe we are getting the
camera from GATAN.

Hope this is of use.

milt scholl

In article <43886@ogicse.ogi.edu> Milt Scholl, milts@mse.cse.ogi.edu
writes:
>Actually we are in the process of putting a 1024X1024X24 bit camera
>in our 200 KV hitachi.  .......  There is a
>device of some type between the ccd and the beam, so you don't get
>200 kv electrons zipping through the ccd - electrons go REAL far in
>silicon and other semiconductors.  I believe we are getting the
>camera from GATAN.

The Gatan CCD cameras have a YAG scintillator which is coupled to the CCD 
through a fiber optic plate. More information may be found directly from
Gatan

USA: tel (415) 463 0200 or (412) 776 5260
UK : tel 536 743 150

There are also some other manufacturers bringing out CCD cameras for the
TEM.

Good luck.

In article <43886@ogicse.ogi.edu>, milts@mse.cse.ogi.edu (Milt Scholl) writes:
|> Actually we are in the process of putting a 1024X1024X24 bit camera
|> in our 200 KV hitachi.  You can do it two ways a camera with an
|> axis parallel to the beam looking down at the phosphor screen (but
|> there are problems with stray electrons, x-rays in the column) or,
|> as we are doing, using a ccd camera specifically made to fit in
|> the column and intersect the beam with the detector.  There is a
|> device of some type between the ccd and the beam, so you don't get
|> 200 kv electrons zipping through the ccd - electrons go REAL far in
|> silicon and other semiconductors.  I believe we are getting the
|> camera from GATAN.

yes, but you're still converting to light- the original posters were
wanting to blow off the scintillator and just capture the electrons which,
as you said, would penetrate far into Si and probably fry things very nicely.

Out of curiousity, since the phosphor screen produces around a single 
wavelength (660nm?), why are you using a (presumably) color camera w/ 
8-bit for RGB (=24bit)?  or do you have multiple screens and are using
multiple magnetic prisms and looking for different compounds simultaneously
or something else radical?

						kevin

ps: BTW, have heard Bad Things about Gatan's quality and support...  

In article <1992Oct9.175017.1901@news2.cis.umn.edu>, Stuart McKernan <stuartm@epx.cis.umn.edu> writes:
|> The Gatan CCD cameras have a YAG scintillator which is coupled to the CCD 
|> through a fiber optic plate. More information may be found directly from
|> Gatan

a couple things to watch out for:

	- Gatan (as well as most suppliers) thins the YAG to decrease 
	  blooming, then coats it with gold to get back some amount of 
	  contrast.  Since the electrons are pounding into gold, x-rays
	  are produced that will, over time, yellow the fiber optic bundle
	  attached.  Also, the TEM should be shielded well enough, but 
	  (especially if you're on an upper floor), you might want to 
	  crank up the scope to its full useful voltage and run a geiger
	  counter around (if on an upper floor, check below the machine)
	  just in case.

	- also, since an optical _bundle_ of fibers is being used, an aliasing
	  effect will be produced (BTW, they couple the scintillator to the
	  CCD to increase quantum efficiency).  As I recall, Gatan post-
	  processes the data to get rid of the 'ringing' that would otherwise
	  be a problem.  As I vaguely recall, their method of deconvolving 
	  this wasn't too sound (IMHO), and you could lose an unspecified
	  amount of high-frequency information which, in our application,
	  wasn't something that we wanted to live with...

						kevin