A better electron microscope

[Jan Panteltje]

Scientists revolutionize microscopy by reimagining the logic of imaging
https://www.sciencedaily.com/releases/2024/08/240801142229.htm

New method significantly reduces the time and damaging radiation used to image fragile specimens
Date:
August 2, 2024
Source:
Trinity College Dublin
Summary:
Scientists have devised an innovative imaging method using state-of-the-art microscopes
that significantly reduces the time and radiation required.
Their work represents a significant breakthrough that will benefit several disciplines,
from materials science to medicine, as the method promises to deliver improved
imaging for sensitive materials such as biological tissues that are especially
vulnerable to damage.

And chips?

[Bill Sloman]

Post by Jan Panteltje
Scientists revolutionize microscopy by reimagining the logic of imaging
https://www.sciencedaily.com/releases/2024/08/240801142229.htm
New method significantly reduces the time and damaging radiation used to image fragile specimens
August 2, 2024
Trinity College Dublin
Scientists have devised an innovative imaging method using state-of-the-art microscopes
that significantly reduces the time and radiation required.
Their work represents a significant breakthrough that will benefit several disciplines,
from materials science to medicine, as the method promises to deliver improved
imaging for sensitive materials such as biological tissues that are especially
vulnerable to damage.
And chips?

The paper claims "Giving microscopists the ability to 'blank' or
'shutter' the electron beam on and off in a matter of nanoseconds in
response to real-time events has never been done before."

It isn't true. The stroboscopic electron microscopes that Cambridge
Instruments sold from about 1983 as electron beam testers could deliver
a half-nanosecond wide pulse of electrons.

The electron beam microfabrictors we'd been selling for year could turn
the beam on and off in less than 10nsec - I worked on the beam-blankers
for both.

Scanning transmission microscopes do use higher voltage electrons, but
that just means that the electrodes that blank the beam have to be
longer. With a half nanosecond wide pulse, you couldn't make the plates
too long for 2kV electrons because the transit time got longer than the
blanking period and I had to invent a solution to get around that, but
"a matter of nanoseconds" give you more wiggle-room.

[John R Walliker]

Post by Bill Sloman

Post by Jan Panteltje
Scientists revolutionize microscopy by reimagining the logic of imaging
  https://www.sciencedaily.com/releases/2024/08/240801142229.htm
New method significantly reduces the time and damaging radiation used
to image fragile specimens
   August 2, 2024
  Trinity College Dublin
  Scientists have devised an innovative imaging method using
state-of-the-art microscopes
  that significantly reduces the time and radiation required.
  Their work represents a significant breakthrough that will benefit
several disciplines,
  from materials science to medicine, as the method promises to
deliver improved
  imaging for sensitive materials such as biological tissues that are
especially
  vulnerable to damage.
And chips?

The paper claims "Giving microscopists the ability to 'blank' or
'shutter' the electron beam on and off in a matter of nanoseconds in
response to real-time events has never been done before."
It isn't true. The stroboscopic electron microscopes that Cambridge
Instruments sold from about 1983 as electron beam testers could deliver
a half-nanosecond wide pulse of electrons.
The electron beam microfabrictors we'd been selling for year could turn
the beam on and off in less than 10nsec - I worked on the beam-blankers
for both.
Scanning transmission microscopes do use higher voltage electrons, but
that just means that the electrodes that blank the beam have to be
longer. With a half nanosecond wide pulse, you couldn't make the plates
too long for 2kV electrons because the transit time got longer than the
blanking period and I had to invent a solution to get around that, but
"a matter of nanoseconds" give you more wiggle-room.

A bigger problem for biological tissues is that they have to be dried
before they can be put in a vacuum chamber and this process can distort
them. They also usually need to be stained with a heavy element such
as uranium for TEM and coated with gold or other conductive materials
for SEM.
John

[Bill Sloman]

Post by John R Walliker

Post by Bill Sloman

Post by Jan Panteltje
Scientists revolutionize microscopy by reimagining the logic of imaging
  https://www.sciencedaily.com/releases/2024/08/240801142229.htm
New method significantly reduces the time and damaging radiation used
to image fragile specimens
   August 2, 2024
  Trinity College Dublin
  Scientists have devised an innovative imaging method using
state-of-the-art microscopes
  that significantly reduces the time and radiation required.
  Their work represents a significant breakthrough that will benefit
several disciplines,
  from materials science to medicine, as the method promises to
deliver improved
  imaging for sensitive materials such as biological tissues that are
especially
  vulnerable to damage.
And chips?

The paper claims "Giving microscopists the ability to 'blank' or
'shutter' the electron beam on and off in a matter of nanoseconds in
response to real-time events has never been done before."
It isn't true. The stroboscopic electron microscopes that Cambridge
Instruments sold from about 1983 as electron beam testers could
deliver a half-nanosecond wide pulse of electrons.
The electron beam microfabrictors we'd been selling for year could
turn the beam on and off in less than 10nsec - I worked on the
beam-blankers for both.
Scanning transmission microscopes do use higher voltage electrons, but
that just means that the electrodes that blank the beam have to be
longer. With a half nanosecond wide pulse, you couldn't make the
plates too long for 2kV electrons because the transit time got longer
than the blanking period and I had to invent a solution to get around
that, but "a matter of nanoseconds" give you more wiggle-room.

A bigger problem for biological tissues is that they have to be dried
before they can be put in a vacuum chamber and this process can distort
them.  They also usually need to be stained with a heavy element such
as uranium for TEM and coated with gold or other conductive materials
for SEM.

There are "environmental SEMs" that work by differential pumping and can
allow enough water vapour around a cold specimen to stop it dehydrating
but not enough to scatter too many of the imaging electrons.

Their commercial success came after my time on electron-microscopes, so
I don't know much about them. My boss from Cambridge Instruments moved
on to FEI so he knew more, and had talked about them, but he died around
2010.

https://en.wikipedia.org/wiki/Environmental_scanning_electron_microscope
--
Bill Sloman, Sydney