X-ray camera makes A-grade particle detector

ScienceDaily (Oct. 11, 2011) — In the particle identification business, two pieces of information are vital: energy and spatial location. By measuring its energy you can work out the mass of your mystery particle. From its spatial location on the surface of a detector, you can work out where the particle came from -- and therefore how big the event was that produced the particle in the first place.

For the range of energies close to one million electron volts (1 MeV) -- a popular energy range to probe, with uses in a variety of fields from cancer treatment research to astrochemistry -- there are currently two leading methods of detecting particles. But both are limited in the types of molecules they can detect, and both sacrifice one type of information -- spatial location or energy measurements -- for the other.

Now a group of nuclear physicists and molecular scientists from the Université Paris Sud and Hamamatsu Photonics have demonstrated a new type of detector that can do both of these jobs at the same time. Their device uses the CCD image sensor chip in a particular off-the-shelf X-ray camera. In the study, described in a paper accepted to the AIP's Review of Scientific Instruments, the experimenters accelerated charged atoms (or ions) of carbon at various energies above 1 MeV, then "caught" those atoms with the camera. A single ion impact with the camera produced a bright spot on the image sensor.

They also accelerated molecules containing carbon and hydrogen. Unfortunately, these bigger particles overwhelmed the CCD chip, wiping out the details.

To avoid saturating the sensor, the researchers came up with the solution of putting a piece of thin carbon foil in front of it. The foil breaks up the projectile molecules that collide with it and sends them, like shrapnel, to the sensor to be counted. The foil also allowed them to separate different types of molecules from one another when the molecules' signatures would otherwise have overlapped.

The researchers say they hope their new detector will open the door to a new class of tools in the study of complex molecules using high-energy accelerators.

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The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by American Institute of Physics, via EurekAlert!, a service of AAAS.

Journal Reference:

M. Chabot, G. Martinet, K. Be´roff, T. Pino, S. Bouneau, B. Genolini, X. Grave, K. Nguyen, C. le Gailliard, P. Rosier, G. Fe´raud, H. Friha, B. Villier. Detection of atomic and molecular mega-electron-volt projectiles using an x-ray charged coupled device camera. Review of Scientific Instruments, 2011; 82 (10): 103301 DOI: 10.1063/1.3640411

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

X-ray camera makes A-grade particle detector

ScienceDaily (Oct. 11, 2011) — In the particle identification business, two pieces of information are vital: energy and spatial location. By measuring its energy you can work out the mass of your mystery particle. From its spatial location on the surface of a detector, you can work out where the particle came from -- and therefore how big the event was that produced the particle in the first place.

For the range of energies close to one million electron volts (1 MeV) -- a popular energy range to probe, with uses in a variety of fields from cancer treatment research to astrochemistry -- there are currently two leading methods of detecting particles. But both are limited in the types of molecules they can detect, and both sacrifice one type of information -- spatial location or energy measurements -- for the other.

Now a group of nuclear physicists and molecular scientists from the Université Paris Sud and Hamamatsu Photonics have demonstrated a new type of detector that can do both of these jobs at the same time. Their device uses the CCD image sensor chip in a particular off-the-shelf X-ray camera. In the study, described in a paper accepted to the AIP's Review of Scientific Instruments, the experimenters accelerated charged atoms (or ions) of carbon at various energies above 1 MeV, then "caught" those atoms with the camera. A single ion impact with the camera produced a bright spot on the image sensor.

They also accelerated molecules containing carbon and hydrogen. Unfortunately, these bigger particles overwhelmed the CCD chip, wiping out the details.

To avoid saturating the sensor, the researchers came up with the solution of putting a piece of thin carbon foil in front of it. The foil breaks up the projectile molecules that collide with it and sends them, like shrapnel, to the sensor to be counted. The foil also allowed them to separate different types of molecules from one another when the molecules' signatures would otherwise have overlapped.

The researchers say they hope their new detector will open the door to a new class of tools in the study of complex molecules using high-energy accelerators.

Recommend this story on Facebook, Twitter,
and Google +1:

Other bookmarking and sharing tools:

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by American Institute of Physics, via EurekAlert!, a service of AAAS.

Journal Reference:

M. Chabot, G. Martinet, K. Be´roff, T. Pino, S. Bouneau, B. Genolini, X. Grave, K. Nguyen, C. le Gailliard, P. Rosier, G. Fe´raud, H. Friha, B. Villier. Detection of atomic and molecular mega-electron-volt projectiles using an x-ray charged coupled device camera. Review of Scientific Instruments, 2011; 82 (10): 103301 DOI: 10.1063/1.3640411

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

Secret behind new gas detector? Chirp before sniffing

ScienceDaily (May 12, 2011) — Trace gas detection, the ability to detect a scant quantity of a particular molecule -- a whiff of formaldehyde or a hint of acetone -- in a vast sea of others, underlies many important applications, from medical tests to air pollution detectors to bomb sniffers. Now, a sensor recently developed at the National Institute of Standards and Technology (NIST) that is hundreds of times faster and more sensitive than other similar technologies may make such detectors portable, economical and fast enough to be used everywhere.

According to the NIST investigators, the new sensor overcomes many of the difficulties associated with trace gas detection, a technique also used widely in industry to measure contaminants and ensure quality in manufacturing. A trace level of a particular gas can indicate a problem exists nearby, but many sensors are only able to spot a specific type of gas, and some only after a long time spent analyzing a sample. The NIST sensor, however, works quickly and efficiently.

"This new sensor can simultaneously detect many different trace gases at very fast rates and with high sensitivity," says NIST chemist Kevin Douglass. "It's also built from off-the-shelf technology that you can carry in your hands. We feel it has great commercial potential."

The key to the new sensor is the use of radiation at "terahertz" frequencies -- between infrared and microwaves. Terahertz waves can make gas molecules rotate at rates unique to each type of gas, which implies the waves hold great promise for identifying gases and measuring how much gas is present. The NIST team has developed the technology to rotate the molecules "in phase" -- imagine synchronized swimmers -- and detect the spinning molecules easily as they gradually fall out of phase with each other.

A major hurdle the new technology overcomes is that it is now possible to look at nearly all possible gas molecules instantly using terahertz frequencies. Previously, it was necessary to expose molecules to a vast range of terahertz frequencies -- slowly, one after another. Because no technology existed that could run through the entire frequency band quickly and easily, the NIST team had to teach their off-the-shelf equipment to "chirp."

"The sensor sends a quick series of waves that run the range from low frequency to high, sort of like the 'chirp' of a bird call," says Douglass. "No other terahertz sensor can do this, and it's why ours works so fast. Teaching it to chirp in a repeatable way has been one of our team's main innovations, along with the mathematical analysis tools that help it figure out what gas you're looking at."

The NIST team has applied for a patent on its creation, which can plug into a power outlet and should be robust enough to survive in a real-world working environment.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by National Institute of Standards and Technology (NIST).

Journal Reference:

Eyal Gerecht, Kevin O. Douglass, David F. Plusquellic. Chirped-pulse terahertz spectroscopy for broadband trace gas sensing. Optics Express, 2011; 19 (9): 8973 DOI: 10.1364/OE.19.008973

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

Secret behind new gas detector? Chirp before sniffing

ScienceDaily (May 12, 2011) — Trace gas detection, the ability to detect a scant quantity of a particular molecule -- a whiff of formaldehyde or a hint of acetone -- in a vast sea of others, underlies many important applications, from medical tests to air pollution detectors to bomb sniffers. Now, a sensor recently developed at the National Institute of Standards and Technology (NIST) that is hundreds of times faster and more sensitive than other similar technologies may make such detectors portable, economical and fast enough to be used everywhere.

According to the NIST investigators, the new sensor overcomes many of the difficulties associated with trace gas detection, a technique also used widely in industry to measure contaminants and ensure quality in manufacturing. A trace level of a particular gas can indicate a problem exists nearby, but many sensors are only able to spot a specific type of gas, and some only after a long time spent analyzing a sample. The NIST sensor, however, works quickly and efficiently.

"This new sensor can simultaneously detect many different trace gases at very fast rates and with high sensitivity," says NIST chemist Kevin Douglass. "It's also built from off-the-shelf technology that you can carry in your hands. We feel it has great commercial potential."

The key to the new sensor is the use of radiation at "terahertz" frequencies -- between infrared and microwaves. Terahertz waves can make gas molecules rotate at rates unique to each type of gas, which implies the waves hold great promise for identifying gases and measuring how much gas is present. The NIST team has developed the technology to rotate the molecules "in phase" -- imagine synchronized swimmers -- and detect the spinning molecules easily as they gradually fall out of phase with each other.

A major hurdle the new technology overcomes is that it is now possible to look at nearly all possible gas molecules instantly using terahertz frequencies. Previously, it was necessary to expose molecules to a vast range of terahertz frequencies -- slowly, one after another. Because no technology existed that could run through the entire frequency band quickly and easily, the NIST team had to teach their off-the-shelf equipment to "chirp."

"The sensor sends a quick series of waves that run the range from low frequency to high, sort of like the 'chirp' of a bird call," says Douglass. "No other terahertz sensor can do this, and it's why ours works so fast. Teaching it to chirp in a repeatable way has been one of our team's main innovations, along with the mathematical analysis tools that help it figure out what gas you're looking at."

The NIST team has applied for a patent on its creation, which can plug into a power outlet and should be robust enough to survive in a real-world working environment.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by National Institute of Standards and Technology (NIST).

Journal Reference:

Eyal Gerecht, Kevin O. Douglass, David F. Plusquellic. Chirped-pulse terahertz spectroscopy for broadband trace gas sensing. Optics Express, 2011; 19 (9): 8973 DOI: 10.1364/OE.19.008973

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here