With a Sentech vacuum sensor, Delmic's SECOM 2.0 is conquering the international microscopy world. This is the only device in the world that enables fluorescence and electron microscopy in one integrated setup. The unique microscope is compatible with all types of SEM electron microscopes.
Sentech has developed a vacuum-compatible optical encoder solution for sample positioning in the vacuum chamber. The independent sensor integrator supplies the solution as a sensor assembly, allowing Delmic to easily integrate it into the SECOM 2.0.
Combination of fluorescence and electron microscopy
At Delmic, 13 people work on the development and manufacturing of high-quality microscopy technology. Its product range offers SPARC solutions for materials research, and SECOM solutions for biomedical research, among others.
“Delmic combines fluorescence and electron microscopy in the SECOM system,” begins Andries Effting, CTO and co-founder of Delmic. The correlative light and electron microscope (CLEM) can be integrated as a module into almost any scanning electron microscope (SEM).
The physicist is building on research from TU Delft and AMOLF with his colleague Sander den Hoedt. In 2011, that research resulted in the SECOM 1.0 prototype.
“It took us about 2 years to bring a suitable microscope to market from the prototype. The SECOM 2.0 looks very different from the prototype, but the concept has remained the same,” according to Effting.
With the high-tech microscopy technologies in Delmic's system, scientists are conducting groundbreaking biomedical research.
Fluorescence microscopy
Fluorescence microscopy, invented in the 1970s, is an optical method for investigating cell function. Researchers add chemical markers to a specimen, which bind to specific proteins.
In the image produced by the microscope, the marked proteins light up in various colors. Proteins are responsible for all processes in living cells. With fluorescence microscopy, scientists gain insight into processes that lead to disease.
Electron Microscopy – TEM and SEM
A electron microscope shoots a beam of electrons toward the specimen to be examined. Accelerated electrons have a much smaller wavelength than photons (light), allowing for a resolution that can be 2000 times higher than an optical microscope.
A transmission electron microscope (TEM) shoots an electron beam through the specimen, creating a kind of slide projection. The method allows for magnifications up to one million times: 0.1 nanometers.
A scanning electron microscope (SEM) focuses electrons towards the material and captures the backscattered electrons point by point to create an image. SEM enables magnifications up to 100,000 times and very sharp 3D images.
Benefits of CLEM for medical science.
According to Effting, Delmic's CLEM has several advantages over standalone systems:
- Ease of use
The researcher no longer needs to make two recordings with separate devices and then process them in software. - New research opportunities
Short-shelf-life preparations can be investigated. The actual uptake of a preparation takes only 1 minute. - Technical quality of the recordings
The recordings offer incredible levels of detail that are not possible with other devices. - Time saving
When research time is a factor, the system offers enormous time savings. Short machine time, for example, allows for rapid population studies.
Featured Benefit: Open Source Software
Effting jokingly calls his company “a photo company.” This explains Delmic's choice to offer its customers open-source software for image processing. “The software just has to be good,” he believes.
“Excellent software ensures a better product experience. We see our software as the instrument's calling card. Competitors leave gaps there. When our customers discover a bug or problem, we simply fix it. They don't have to wait for releases and updates, and they don't pay license fees, but they do pay for the actual support provided. Open source offers transparency to the user. The code is simply online,” according to the CTO.
Integration into almost all SEM types
“We provide the optical microscope and software,” Effting explains. “There are plenty of companies that supply excellent SEMs. Our system fits on the SEMs of the five major suppliers, such as ZEISS, Tescan, Hitachi, Fei, and JEOL.”
The SECOM stage replaces the SEM stage. Effting continues: “For this, we developed microscope-specific interfaces. We optimized the software for each SEM type. Our customers can order the SECOM as an option from the SEM supplier, or directly from Delmic.”
Groundbreaking bioscience research
Delmic's CLEM microscopes are now finding their way to various universities and research institutions around the world.
Dr. Ben Giepmans The microscope is used, for example, in diabetes research by his cell biology research group at the University of Groningen.
He and his scientists are focusing on the Islets of Langerhans in the pancreas. They are thus investigating the triggers and new treatment methods for type 1 diabetes.
The Francis Crick Institute, under the leadership of microbiologist Lucy Collinson, uses SECOM for cancer research, among other applications.
Vacuum sensor development for the vacuum space
The SECOM 2.0 owes its extreme accuracy and high resolution to a unique optical vacuum sensor. Sentech supplies the customized MicroE optical sensors in a fully tested and calibrated assembly.
Delmic receives three sensor assemblies per CLEM system, one for each axis of movement, which can be quickly and easily assembled.
Encoder sensor MicroE for precise positioning
Delmic was looking for a reliable sensor solution for accurately positioning the sample in the vacuum chamber. Sentech came onto Delmic's radar after a Google search.
This led to a joint search for a suitable sensor solution based on the accuracy requirements and the circumstances of the internship.
Peter Verstappen, account manager at Sentech, explains the development process. “The challenges were: accuracy, vacuum conditions, and the limited installation volume. We're talking about nanometers and an extremely precise focal point for the optical microscope.”
Accurate position sensor – material usage and low energy consumption
The vacuum limited the search spectrum for the position sensor in terms of material usage and energy consumption. In a vacuum, outgassing occurs with various materials such as plastics, which ‘contaminates’ the sample and environment.
Another problem is the lack of air cooling. Therefore, a sensor was needed that generates as little heat as possible.
“We put the entire MicroE line, along with a position sensor, through testing, as well as a number of competitors. Based on the specifications, the 90% was immediately ruled out,” said Verstappen.
Effting reacts: “We quickly agreed on the application of a MicroE optical encoder. It was pleasant to be able to talk about our wishes and the specifications in an easy way.”
How an optical encoder works
The optical sensors determine their position on the motion axis using a read head and a very fine ruler, on which a pattern of lines is placed with a period of 20 µm.
The linear optical encoder does not contain an LED as a light source, but a VCSEL-controlled element that requires much less energy. The absence of a lens also contributes to the most compact possible position sensor.
“We adjusted the ruler according to the accuracy requirements,” said Verstappen. The light source shines on a pattern of reflective and non-reflective stripes, creating ‘nodes’ in the reflection pattern.
These are coinciding crests and troughs of the specific wavelength and are captured by the sensor receiver. Similar to the principle of light passing through a diffraction grating. This way, a displacement can be made visible per period in a movement.
Incremental measuring system with interpolation
The incremental measuring system converts movement into counting pulses. The movement is accurately controlled with respect to a fixed unique point on the ruler: the index.
Verstappen on accuracy: “The sensor interpolates the intrinsic period of 20 micrometers to steps of 1.2 nanometers, or a multiple thereof. We needed the highest accuracy for the z-axis movement.”
He continues: “For cost and handling reasons, we have decided to use the optical nanosensor for each axis.”
High-quality materials in optical sensor assembly
Sentech and Delmic have paid a lot of attention to the quality of the other components, in addition to the specific sensor. Effting wanted to avoid discussions with various suppliers about sensor components.
“We offer a high-tech system. Then you shouldn't skimp on costs with cheap connectors and cabling, for example. You don't want hassle about liability afterwards.”
Semiconductor industry experience
Sentech utilized its experience in the semiconductor industry. “That's why we chose the standards and high quality from the semiconductor industry and advised Delmic to solder the connections rather than screw them,” explains Verstappen.
The semiconductor experience also led to the logical choice of producing and packaging the sensor assembly in Sentech's cleanroom.
“Sentech makes it incredibly easy for us because we know that the complete sensor application has been tested. In our assembly facility, we just need to take the sensors out of the packaging, and we can assemble them directly and quickly,” says the satisfied Delmic founder.
Conquering the world with reliable sensors
According to Effting, satisfaction with Sentech doesn't just stem from the pleasant collaboration in an open development environment. “The SECOM 2.0 has been on the market since 2013. To date, all sensors have been working flawlessly. The promised specifications and performance have been delivered.”
The SECOM platform has proven its worth and is slowly but surely conquering the microscopy world.
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