When you’re in the market for a new piece of equipment for your laboratory, it can be tough to know where to start. An essential purchase is a scanning electron microscope (SEM), which allows you to see the surface features of objects at high magnification.
There are many different types of high-power microscopes on the market, each with its strengths and weaknesses. So how do you know which SEM suits your needs? In this blog, we’ll outline some factors to consider when choosing an SEM for your laboratory.
Before we get to the actual list, let’s first define what’s an SEM and describe how it works.
What is Scanning Electron Microscopy?
Scanning electron microscopy (SEM) is a type of microscopy that uses a focused beam of electrons to obtain high-resolution images of a sample. The electrons interact with the atoms in the sample, causing them to emit signals that end-users can use to create an image.
SEM can be used to obtain images of microscopic features, making it an essential tool for research in many scientific disciplines. High-power microscopes are necessary to produce an SEM image, and the development of these microscopes has dramatically increased our ability to study the world around us.
SEM is just one type of microscopy, and many other methods are available to obtain images of samples. However, SEM provides some unique advantages that make it a valuable tool for many scientists.
How Does Scanning Electron Microscopy Work?
Powerful microscopes have transformed our ability to see and understand the world around us. The scanning electron microscope (SEM) is one of the most powerful microscopes available, capable of magnifying objects up to 100,000 times their actual size. But how does this incredible instrument work?
At its core, the SEM uses a beam of electrons to create a detailed image of an object. The electrons are produced by an electron gun and then accelerated towards the object being studied. When the electrons hit the object’s surface, they interact with the atoms in the material, causing them to emit photons. These photons are then detected by an imaging system, which creates a high-resolution image of the object.
One of the benefits of using electrons instead of light to create an image is that it’s possible to obtain a much higher resolution. In fact, with a properly calibrated SEM, it is possible to see objects as small as 0.1 nanometers in size! This makes the instrument an invaluable tool for scientists and engineers who need to study microscopic objects.
Primary Considerations When Selecting an SEM
Magnification is one of the most critical performance specifications of an SEM, and it will determine how much detail you can see in your images.
Scanning electron microscopes come in a wide range of magnifications, from 10x to 500,000x. The microscope magnification you need will depend on the intended use of the instrument. For example, a lower magnification would suffice if you need to observe large objects or areas.
However, a higher magnification would be necessary if you need to view tiny details or make precise measurements, a higher magnification would be necessary. Keep in mind that the higher the magnification, the higher the cost of the microscope.
Another primary consideration when selecting an SEM is resolution. It covers the ability of the microscope to resolve small features on the surface of the specimen.
The resolution of an SEM is determined by several factors, including the type of electron optics used, the size of the electron beam, and the way in which the specimen is prepared. In general, higher resolution microscopes are more expensive, but they offer users the ability to obtain more detailed information about their specimens.
Similar to magnification, it’s vital to consider the specific needs of your application to ensure that you select an SEM with sufficient resolution.
The next consideration to keep in mind when choosing an SEM is the user’s intended application. What will the microscope be used for? Will it be used for simple inspections or for more complex analyses? Of equal importance is the type of sample. Is the sample brittle or fragile? What is its size and shape?
Knowing the answers to these questions will help you to determine the most suitable model and specs for your needs.
When deciding what type of SEM to buy or use, consider the number of people who will use the system, their level of training, and the length of time it will take to train them.
While floor-based systems with built-in automation are easy to use, training is necessary to maximize effectiveness and performance. Tabletop SEMs are less complicated and require substantially less training for most applications.
It may not appear necessary, but considering ergonomics while choosing a scanning electron microscope can be advantageous.
Laboratory professionals, particularly those working in clinical labs, often spend significant time looking through a microscope. Make sure your microscopes fit the user’s body to reduce the danger of back, neck, shoulder, and arm injuries.
Questions to Ask When Buying an SEM
- What is the finest resolution you want to achieve?
- What is the speed of the microscope that you require?
- Will you need a floor model SEM or a smaller desktop model? (Note: Desktop models are often more affordable in price.)
- Does your laboratory have sufficient space or a dedicated room for the SEM?
- What service and warranty options are available for the SEM?
- What ergonomic features are available?
- How many individuals will use the microscope, and how will they be trained?
Undoubtedly, an SEM is a powerful tool used by scientists and researchers to get a closer look at the structure of materials.
By understanding how SEM works, researchers can select the right instrument for their needs and ask the right questions when purchasing an SEM. With so many different types of SEMs available on the market, it’s important to know what you need to make an informed decision.
We hope this article has helped you learn more about scanning electron microscopy and will guide you in making the best purchase for your laboratory or research facility. Have any questions or reactions? Leave us a comment below!
Frequently Asked Questions
How much does a quality scanning electron microscope typically cost?
Several factors can affect the price of an SEM, including the features you need, the brand you choose, and where you purchase it from. However, you can typically expect to pay anywhere from $30,000 to $100,000 for a quality SEM. Of course, this is a sizable investment, so be sure to do your research before making a purchase.
What are the main benefits of using a scanning electron microscope?
There are many advantages to using an SEM over other microscopy techniques. One key advantage is that SEMs can achieve much higher resolutions than other microscopes, making them ideal for studying small features or fine details.
In addition, SEMs can be used to examine a wide variety of samples, including those that are fragile or difficult to prepare. Finally, SEMs can be used to perform a variety of analyses on samples, such as elemental composition or topographical mapping.
Overall, the versatility and power of SEMs make them an invaluable tool for researchers in a wide range of fields.
What are some of the limitations of a scanning electron microscope?
Scanning electron microscopes are one of the most powerful tools in the scientific arsenal, capable of magnifying objects up to 500,000 times their actual size. However, there are a few limitations to consider when using this type of microscope.
First, the vacuum required to operate a scanning electron microscope can be difficult to maintain, and even small leaks can cause damage to the equipment. In addition, because they rely on a beam of electrons to create an image, scanning electron microscopes can only be used on materials that are conductive or coated with a conductive film.
Finally, scanned images can sometimes be distorted by the electrons as they interact with the sample. Despite these limitations, scanning electron microscopes remain an invaluable tool for scientists and engineers who need to view microscopic objects in great detail.