Articles

Performance of 1mm² Silicon Photomultipliers

A silicon photomultiplier (SPM) is a new type of semiconductor detector that has the potential to replace the photomultiplier tube (PMT) detector in many applications. In common with a PMT detector, the output of an SPM is an easily detectable current pulse for each detected photon and can be used in both photon counting mode and as an analogue (photocurrent) detector. However, the SPM also has a distinct advantage over PMT detectors. The photon-induced current pulse from a PMT varies greatly from photon to photon, due to the statistics of the PMT multiplication process (excess noise). In contrast, the current pulse from an SPM is identical from photon to photon. This gives the SPM a distinct advantage in photon counting applications as it allows the associated electronics to be greatly simplified. Identical pulses also mean that the SPM can resolve the number of photons in weak optical pulses, so-called photon number resolution. This is critical in a number of applications including linear-optics quantum computing.

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Touch Screen Technology 101

What makes the iPhone so great? Touch screen technology. Touch screens are changing the way we interact with technology and with iPhone, Apple has opened the floodgates of innovation for the function and design of handheld devices.

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Prototyping PMC Daughterboards

The PMC, or PCI Mezzanine Card, follows the IEEE P1386.1 standard for printed circuit boards. PMCs combine the electrical characteristics of the PCI bus with the mechanical dimensions of the Common Mezzanine Card, or CMC, format. Within the PMC format single PMC boards measure 74mm × 149mm. While the standard also defines a double-sized card, this format is rare. For PMC cards, as defined by the standard, connector configurations can be: 2 bus connectors (P1 and P2) supporting 32-bit PCI signals, 3 bus connectors (P1, P2 and P3) supporting 64 bit PCI signals, and/or 4th bus connector (P4) supporting non-specified I/O signals.

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Techniques for Cooling Power and Other Electronic Devices

All electronic devices generate heat due to their unavoidable internal losses and inefficiencies. The higher the efficiency rating of the device, the less internal heat is generated within it. If we could achieve 100% efficiency, and technology is getting ever closer to that elusive goal, no heat would be generated within the device and, therefore, no cooling would be required. Until then, the generated heat must be dissipated to maximize the end product’s reliability and prevent its premature failure.

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Fly-by-Wireless: A Less-Wire and Wireless Revolution for Aerospace Vehicle Architectures

By George Studor, NASA’s Johnson Space Center, Houston, TX Every ounce of weight brought to the lunar surface costs 40 to 60 times that in fuel needed at liftoff from the Earth. Part of that weight penalty is due to wires, but the cost of wires is much more than weight. Wired connectivity drives up the price of design from the beginning: it drives the cost of the many systems and structures; it drives inspection, troubleshooting, maintenance, and upgrade costs; as well as the cost of making system changes. Future vehicles that can reduce the effects and limitations of wires will not be without risk or a lot of work, but the effort has begun.

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Performance of 1mm2 Silicon Photomultipliers

A silicon photomultiplier (SPM) is a new type of semiconductor detector that has the potential to replace the photo- multiplier tube (PMT) detector in many applications. In common with a PMT detector, the output of an SPM is an easily detectable current pulse for each detected photon and can be used in both photon counting mode and as an analogue (photocurrent) detector. However, the SPM also has a distinct advantage over PMT detectors. The photon-induced current pulse from a PMT varies greatly from photon to photon, due to the statistics of the PMT multiplication process (excess noise). In contrast, the current pulse from an SPM is identical from photon to photon. This gives the SPM a distinct advantage in photon counting applications as it allows the associated electronics to be greatly simplified. Identical pulses also mean that the SPM can resolve the number of photons in weak optical pulses, so-called photon number resolution. This is critical in a number of applications including linear-optics quantum computing.

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Printed Flexible Solar Cells Provide Embedded Renewable Power

In the effort to produce inexpensive, easily manufactured sources of sustainable, renewable power, solar cells continue to be a major focus — particularly flexible solar cells that can be applied directly to surfaces. Flexible solar cells are nothing new, but the methods by which they are made have progressed significantly in recent years.

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