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Board-level EMI shielding: DIY in minutes

ProtoShield sheets from Tech-Etch are depth-etched with a checkerboard pattern for folding, so they can be easily formed into many diverse configurations. In the product-development stage, fully functional shields can be created in minutes with just a pair of scissors and a straight edge for folding. Offered in two sizes: standard (.25-in. squares) and metric (5-mm squares). Both versions are solderable and corrosion resistant due to nickel silver material. Shield prototypes can be directly soldered to the board, or shield clips can be used for easy mounting. Samples available.
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Isolated probing tech for fast-switching power device testing

Keysight Technologies has developed an optically isolated differential probing family dedicated to enhancing efficiency and performance testing of fast-switching devices such as wide-bandgap GaN and SiC semiconductors. Validation of floating half-bridge and full-bridge architectures commonly used in power conversion, motor drives, and inverters requires measurement of small differential signals riding on high common-mode voltages. This measurement can be challenging due to voltage source fluctuations relative to ground, noise interference, and safety concerns.
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Protect sensitive electronics in explosive environments with new aluminum ATEX Cabinet Cooler Systems

EXAIR's ATEX Cabinet Cooler^® Systems deliver a powerful and affordable solution for keeping electrical enclosures cool in hazardous ATEX classified areas -- and they're now available in durable aluminum construction. Engineered for use in Zones 2 and 22, these coolers are UL tested, CE compliant, and meet stringent ATEX standards for purged and pressurized enclosures. With cooling capacities up to 5,600 Btu/Hr., ATEX Cabinet Coolers are ideal for preventing overheating in electrical cabinets. EXAIR offers a comprehensive lineup of systems.
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PLC handbook chock full of must-know information

Automation-Direct's Practical Guide to Program-mable Logic Controllers Handbook has been improved with tons of new need-to-know info, making it a more comprehensive guide to the world of PLCs. Besides covering the basics of PLC history, PLC hardware, and PLC software, this guide takes you deeper into the ever-changing world of PLC communication, the importance of feedback loops, cyber security, and many other areas that are a must-know for any PLC novice or seasoned automation professional.
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Haptic feedback prototyping kit from TDK

Get your customers to feel the difference your products make. TDK has released a development starter kit for fast haptics prototyping. It gives mechanical designers and engineers first impressions of the haptic feedback using PowerHap piezo actuators, shows how the mechanical integration works, and provides a reference design. Applications include automotive, displays and tablets, household appliances, vending machines, game controllers, industrial equipment, and medical devices.
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Mini ESD preset torque screwdriver

Need precision fastening with ESD protection at the smallest torque levels? Mountz has you covered. The new FG Mini ESD Preset Torque Screwdriver is built for low-torque, high-precision tasks. Its compact design makes it ideal for tight spaces and small fasteners, while delivering the same reliable control and ESD protection users have come to expect from Mountz. Two models available: FG25z (3 to 25 ozf.in, 2 to 17.7 cN-m) and FG50z (20 to 50 ozf.in, 14.1 to 35.3 cN-m).
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Laumas load cells and electronics from AutomationDirect

Automation-Direct has added Laumas precision-engineered load cells, transmitters, and accessories that deliver reliable performance in industrial weighing and force measurement applications. The FCAL series high-precision bending beam load cells are ideal for low- to mid-capacity systems. CTL series load cells are designed for both tension and compression, with excellent linearity. The CBL series low-profile compression load cells are perfect for space-limited applications. Laumas load cell transmitters are available too for precise monitoring and control. Very good pricing.
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Engineer's Toolbox: What is ground loop feedback?

Improper grounding can create problems in data logging, data acquisition, and measurement and control systems. One of the most common problems is known as ground loop feedback. Experts at CAS DataLoggers run through five ways to eliminate this problem.
Read the full article.

What is a braking resistor?

According to Automation-Direct, "Braking resistors don't actually provide braking directly -- rather, they allow a drive to stop a loaded motor faster." Why is this important? Protect your AC or DC drive system from regenerative voltage that can create an over-voltage fault on the drive -- especially with high inertial loads or rapid deceleration.
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New Digital Static Meter: Precise measurement, easy use

Static electricity isn't just a nuisance; it's a serious threat to manufacturing efficiency, product integrity, and workplace safety. Unchecked static can lead to costly downtime, product defects, material jams, and even hazardous shocks to employees. If static is interfering with your processes, EXAIR's upgraded Model 7905 Digital Static Meter offers an essential first step in identifying and eliminating the problem. With just the press of a button, this easy-to-use, handheld device pinpoints the highest voltage areas in your facility, helping you diagnose static issues before they become a problem.
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New laser cutting modulating strategy tested with Mikrotron high-speed camera

Modulating a laser beam's intensity distribution optimizes energy delivery to the process zone, resulting in better cutting speed, cut edge quality, and cut kerf geometry. Scientists in Belgium have come up with a new method that they say produces better cutting results.
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All-in-one embedded PLC based on Raspberry Pi 4 -- build control applications

The new PLC CPI-PS10CM4 from Contec Co. is a compact embedded programmable logic controller (PLC) that is loaded with CODESYS, the world's most widely used software PLC. This product uses Contec's original single-board computer, which is based on Raspberry Pi's latest embedded module, the Compute Module 4 (CM4). By using the wide range of peripheral devices for Raspberry Pi, such as Contec's CPI Series, you can build various control applications in a PLC language that complies with the IEC 61131-3 international standard.
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Torque sensors for fastening applications and more

Saelig Company has introduced the Sensor Technology SGR525/526 Series Torque Sensors to provide precision torque monitoring that is critical for performance and safety. The square drive design (for applications with non-cylindrical shafts) allows for seamless integration into power tools, test rigs, industrial machinery, and precision fastening applications, ensuring superior torque measurement without the need for additional adapters or modifications. The SGR525 offers torque measurement only, while the SGR526 provides torque, speed, and power measurement using a 360-pulse-per-revolution encoder. Industries include automotive, aerospace, manufacturing, and research and development.
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Wide-angle camera optimized for larger, faster conveyor belts

Wider conveyor belts operating at higher speeds are now commonplace in modern logistics. To keep up, SVS-Vistek is offering a cost-effective alternative to multi-camera systems with its fxo901CXGE 10-GigE color camera featuring the Sony IMX901-AQR wide-aspect global shutter 16.4-megapixel CMOS sensor. Unlike standard cameras, this unit captures targets in a wide field of view while maintaining high resolutions. The 4:1 horizontal aspect ratio allows one fxo901CXGE to replace an entire multi-camera system, removing the need for image synchronization.
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Handheld thermal imager cuts diagnostic time

The FLIR TG268 is a next-generation thermal imager that provides professionals in the utility, manufacturing, electrical, automotive, and industrial sectors with a lightweight, handheld, affordable condition monitoring tool. Latest enhancements include higher temperature ranges, improved resolution, and larger data storage capacity. Go beyond the restrictions of single-spot IR thermometers to view and evaluate hot and cold spots that may signify potentially dangerous issues. Accurately measure temps from -25 to 400 C. Native thermal images improved with Super Resolution upscaling.
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U.S. scientists make matter and antimatter from light

A new study demonstrates a long-predicted process for generating matter directly from light -- plus evidence that magnetism can bend polarized photons along different paths in a vacuum.

Scientists studying particle collisions at the Relativistic Heavy Ion Collider (RHIC), a U.S. Department of Energy Office of Science user facility for nuclear physics research at DOE's Brookhaven National Laboratory, have produced definitive evidence for two physics phenomena predicted more than 80 years ago. The results were derived from a detailed analysis of more than 6,000 pairs of electrons and positrons produced in glancing particle collisions at RHIC and are published in Physical Review Letters.

The primary finding is that pairs of electrons and positrons -- particles of matter and antimatter -- can be created directly by colliding very energetic photons, which are quantum "packets" of light. This conversion of energetic light into matter is a direct consequence of Einstein's famous E=mc² equation, which states that energy and matter (or mass) are interchangeable. Nuclear reactions in the sun and at nuclear power plants regularly convert matter into energy. Now scientists have converted light energy directly into matter in a single step.

Making matter from light: Two gold (Au) ions (red) move in opposite directions at 99.995% of the speed of light (v, for velocity, = approximately c, the speed of light). As the ions pass one another without colliding, two photons (γ) from the electromagnetic cloud surrounding the ions can interact with each other to create a matter-antimatter pair: an electron (e^-) and positron (e⁺).

 

 

 

 

The second result shows that the path of light traveling through a magnetic field in a vacuum bends differently depending on how that light is polarized. Such polarization-dependent deflection (known as birefringence) occurs when light travels through certain materials. (This effect is similar to the way wavelength-dependent deflection splits white light into rainbows.) This new work is the first demonstration of polarization-dependent light-bending in a vacuum.

Both results depend on the ability of RHIC's STAR detector -- the Solenoid Tracker at RHIC -- to measure the angular distribution of particles produced in glancing collisions of gold ions moving at nearly the speed of light.

Colliding clouds of photons
Such capabilities didn't exist when physicists Gregory Breit and John A. Wheeler first described the hypothetical possibility of colliding light particles to create pairs of electrons and their antimatter counterparts, known as positrons, in 1934.

"In their paper, Breit and Wheeler already realized this is almost impossible to do," said Brookhaven Lab physicist Zhangbu Xu, a member of RHIC's STAR Collaboration. "Lasers didn't even exist yet! But Breit and Wheeler proposed an alternative: accelerating heavy ions. And their alternative is exactly what we are doing at RHIC."

The STAR detector at the Relativistic Heavy Ion Collider measured the angular distribution of particles produced in glancing collisions of gold ions moving at nearly the speed of light to provide evidence for two physics phenomena predicted more than 80 years ago.

 

 

 

 

An ion is essentially a naked atom, stripped of its electrons. A gold ion, with 79 protons, carries a powerful positive charge. Accelerating such a charged heavy ion to very high speeds generates a powerful magnetic field that spirals around the speeding particle as it travels -- like current flowing through a wire.

"If the speed is high enough, the strength of the circular magnetic field can be equal to the strength of the perpendicular electric field," Xu said. And that arrangement of perpendicular electric and magnetic fields of equal strength is exactly what a photon is -- a quantized "particle" of light. "So, when the ions are moving close to the speed of light, there are a bunch of photons surrounding the gold nucleus, traveling with it like a cloud."

At RHIC, scientists accelerate gold ions to 99.995% of the speed of light in two accelerator rings.

"We have two clouds of photons moving in opposite directions with enough energy and intensity that when the two ions graze past each other without colliding, those photon fields can interact," Xu said.

STAR physicists tracked the interactions and looked for the predicted electron-positron pairs.

But such particle pairs can be created by a range of processes at RHIC, including through "virtual" photons, a state of photon that exists briefly and carries an effective mass. To be sure the matter-antimatter pairs were coming from real photons, scientists have to demonstrate that the contribution of "virtual" photons does not change the outcome of the experiment.

To do that, the STAR scientists analyzed the angular distribution patterns of each electron relative to its partner positron. These patterns differ for pairs produced by real photon interactions versus virtual photons.

"We also measured all the energy, mass distributions, and quantum numbers of the systems. They are consistent with theory calculations for what would happen with real photons," said Daniel Brandenburg, a Goldhaber Fellow at Brookhaven Lab, who analyzed the STAR data on this discovery.

Other scientists have tried to create electron-positron pairs from collisions of light using powerful lasers -- focused beams of intense light. But the individual photons within those intense beams don't have enough energy yet, Brandenburg said.

One experiment at the SLAC National Accelerator Laboratory in 1997 succeeded by using a nonlinear process. Scientists there first had to boost the energy of the photons in one laser beam by colliding it with a powerful electron beam. Collisions of the boosted photons with multiple photons simultaneously in an enormous electromagnetic field created by another laser produced matter and antimatter.

"Our results provide clear evidence of direct, one-step creation of matter-antimatter pairs from collisions of light as originally predicted by Breit and Wheeler," Brandenburg said. "Thanks to RHIC's high-energy heavy ion beam and the STAR detector's large acceptance and precision measurements, we are able to analyze all the kinematic distributions with high statistics to determine that the experimental results are indeed consistent with real photon collisions."

Bending light in a vacuum
STAR's ability to measure the tiny deflections of electrons and positrons produced almost back-to-back in these events also gave the physicists a way to study how light particles interact with the powerful magnetic fields generated by the accelerated ions.

"The cloud of photons surrounding the gold ions in one of RHIC's beams is shooting into the strong circular magnetic field produced by the accelerated ions in the other gold beam," said Chi Yang, a long-time STAR collaborator from Shandong University who spent his entire career studying electron-positron pairs produced from various processes at RHIC. "Looking at the distribution of particles that come out tells us how polarized light interacts with the magnetic field."

Bending polarized light: This illustration shows how light with different polarization directions (indicated by black arrows) passes through a material along two different paths (yellow beams). This is called the birefringence effect. Results from RHIC provide evidence that birefringence also happens in a magnetic field in a vacuum.

 

 

 

 

Werner Heisenberg and Hans Heinrich Euler in 1936, and John Toll in the 1950s, predicted that a vacuum of empty space could be polarized by a powerful magnetic field and that such a polarized vacuum should deflect the paths of photons depending on photon polarization. Toll, in his thesis, also detailed how light absorption by a magnetic field depends on polarization and its connection to the refractive index of light in a vacuum. This polarization-dependent deflection, or birefringence, has been observed in many types of crystals. There was also a recent report of the light coming from a neutron star bending this way, presumably because of its interactions with the star's magnetic field. But no Earth-based experiment has detected birefringence in a vacuum.

At RHIC, the scientists measured how the polarization of the light affected whether the light was "absorbed" by the magnetic field.

This is similar to the way polarized sunglasses block certain rays from passing through if they don't match the polarization of the lenses, Yang explained. In the case of the sunglasses, in addition to seeing less light get through, you could, in principle, measure an increase in the temperature of the lens material as it absorbs the energy of the blocked light. At RHIC, the absorbed light energy is what creates the electron-positron pairs.

"When we look at the products produced by photon-photon interactions at RHIC, we see that the angular distribution of the products depends on the angle of the polarization of the light. This indicates that the absorption (or passing) of light depends on its polarization," Yang said.

This is the first Earth-based experimental observation that polarization affects the interactions of light with the magnetic field in the vacuum -- the vacuum birefringence predicted in 1936.

"Both of these findings build on predictions made by some of the great physicists in the early 20th century," said Frank Geurts, a professor at Rice University, whose team built and operated the state-of-the-art "Time-of-Flight" detector components of STAR that were necessary for this measurement. "They are based on fundamental measurements made possible only recently with the technologies and analysis techniques we have developed at RHIC."

Source: Brookhaven National Laboratory

Published September 2021

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