A Chip to Measure Vacuums


Ian Rousseau, CEO of Hexisense, brings to the marketplace a gallium nitride-based chip that can measure vaccums © 2019 Alain Herzog

Vacuums are an important part of the procedures – such as freeze-drying – utilized to make and protect many daily products and need to be determined with accuracy. An EPFL spin-off, Hexisense, is bringing to market a gallium nitride-based chip that can measure the amount of specific gas particles inexpensively and with incomparable accuracy.

What do a mirror, a cup of yogurt, an electrical cars and truck battery and an LED lightbulb share? Their production procedures all need a vacuum, i.e. an environment in which gas particles are eliminated. Generally, when the last drop has actually been put from a bottle, the bottle is thought about empty. Physically, nevertheless, it stays loaded with gas. When a vacuum is needed, suction pumps leave a differing quantity of gas depending upon the procedure utilized. A vacuum is for that reason evaluated on the basis of pressure put in by the variety of particles that stay in the container. This measurement is essential for makers – and an EPFL spin-off is preparing to bring to market a little chip that might make their lives much easier.

A perfect tool for freeze-drying

Let’s take freeze-drying as an example. This is a strategy for maintaining food that preserves its color and texture and the majority of its dietary qualities and taste. It is typically utilized when looking into and producing food and medications, and is extremely energy-intensive and lengthy. Products are dried in a vacuum, and the primary stumbling block is that there is no inexpensive method of identifying the precise minute at which the procedure can be stopped. This indicates that the equipment does more work than is needed. The sensing unit established by EPFL’s Lab of Advanced Semiconductors for Photonics and Electronic devices might conquer this downside by suggesting the staying quantity of water vapor in genuine time.

Vacuum systems consist of numerous recurring gases: nitrogen, oxygen, argon, hydrogen, water vapor and so on. To measure them, makers presently have 2 alternatives. The inexpensive one includes numerous techniques to measure the overall pressure of all those gases on the basis of specifications such as contortion, displacement and heat. The other, mass spectrometry, compares the gases, however cannot be utilized in all systems since the devices is costly. The little 0.4 cm2 chip established and quickly to be marketed by the EPFL spin-off goals to provide an inexpensive method of determining private gases in all vacuum systems.

Utilizing light to unstick gas particles

The mini-sensor harnesses 2 physical qualities of its primary element, gallium nitride: its reactivity to light and its status as a semiconductor. In a vacuum vessel, when gas particles end up being less many, they move towards the walls and stick there. Gallium nitride, when exposed to a light, wards off specific gas particles, like oxygen. So an LED is put on the chip, which unsticks particles from the walls. As soon as the light goes off, gallium nitride’s semiconductor homes permit the chip to measure how rapidly gas particles return to the walls. Particular algorithms then evaluate the variety of particles on the surface area together with the partial pressure of each gas. These small chips boast outstanding effectiveness: for instance, they can discover oxygen within nitrogen at a concentration of less than 0.5%.

A versatile chip that is heat- and shock-resistant

These versatile chips are heat-resistant up to 250°C and do not consist of any microelectromechanical systems, which indicates they can endure mechanical vibrations and shocks. In addition, unlike low-pressure ionization-based vacuum evaluates, these sensing units do not produce ionized particles or electromagnetic fields that might impact specific technical devices. These benefits imply that the new-generation chips are extremely flexible, making life much easier for their users since all they require to do is location the chips within their pressure systems in order to get the information they require.

Production underway

The 2 innovators, Ian Rousseau and Pirouz Sohi, supported by numerous start-up programs such as Bridge – the joint accelerator established by the Swiss National Science Structure and Innosuisse – EPFL Innogrant, Enable and Endeavor Kick, are now beginning to produce these chips. Hexisense, the resultant spin-off business, goals to commercially establish and produce the sensing units, from style to characterization, production and product packaging.

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