• A better electron microscope

    From Jan Panteltje@21:1/5 to All on Wed Aug 7 05:02:24 2024
    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?

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  • From Bill Sloman@21:1/5 to Jan Panteltje on Wed Aug 7 17:29:50 2024
    On 7/08/2024 3:02 pm, Jan Panteltje wrote:
    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?

    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.

    --
    Bill Sloman, Sydney


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  • From Bill Sloman@21:1/5 to John R Walliker on Mon Aug 12 15:42:09 2024
    On 12/08/2024 12:50 am, John R Walliker wrote:
    On 07/08/2024 08:29, Bill Sloman wrote:
    On 7/08/2024 3:02 pm, Jan Panteltje wrote:
    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?

    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






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