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For imaging biological material with sub-nanometer resolution, use helium ions copy (HIM). The gold standard for capturing images of the sub-micrometer surface ultrastructure of both hard and soft materials is scanning electron microscopy (SEM).
It has given valuable insights into the physical architecture of biological samples. Three major issues with SEM imaging of soft materials, meanwhile, are the low imaging resolution at high magnification, charge brought on by the insulating nature of the majority of biological samples, and the loss of fine surface details due to heavy metal coating.
The creation of the Helium Ion Microscope (HIM), which boasts improvements in charge reduction, decreased sample damage, excellent surface contrast without the need for metal coating, enhanced depth of focus, and 5 angstrom imaging resolution, has recently solved these problems.
The benefits of HIM for photographing biological surfaces and contrast the impact of various sample preparation methods on sub-nanometer ultrastructure.
The catch is that in order to use standard SEM imaging, materials must be both vacuum-friendly and conductive, which can be achieved by drying the sample and coating it with a heavy metal.
Although this form of sample preparation has long been the norm, there are some situations in which the metal coating can obscure fine surface details or in which the sample is too fragile or small to withstand the necessary fixing and drying operations.
Many improvements have been made to minimise charge as well as image samples in their hydrated form in order to combat this.
The Global Helium Ion Microscope market accounted for $XX Billion in 2023 and is anticipated to reach $XX Billion by 2030, registering a CAGR of XX% from 2024 to 2030.
The most recent additions to the microscopy toolkit are helium ion microscopes. Helium ion microscope (HIM)ions focused on a tiny point, as the name suggests (a few angstroms in diameter).
Secondary electrons (SEs) are produced as a result of interactions with the material and are counted by a detector. We can get a picture of the sample’s surface by rastering the ion beam across it.
There are several advantages over a scanning electron microscope, including a significantly smaller beam spot size and a high SE yield (SEM).
HIM’s substantially wider field of view and special ability to photograph non-conducting samples without a deposited metal overlayer are its key advantages over other imaging techniques.
The ion source in HIM is a needle-shaped, extremely sharp monocrystalline metal (whose precise composition is a highly held trade secret, but it is usually thought to be W or a W alloy), with only three atoms at the tip (referred to as a trimer).
In comparison to a single atom, the three-atom arrangement enables better stability and, as a result, longer operation durations. Liquid nitrogen is used to cool down the needle.
In addition to reducing background gases and reducing needle vibrations, cooling the ion source improves the stability of the trimer by preventing image blurring caused by ion source vibrations. An electrical supply with a positive high voltage is linked to the needle.
