South Pole telescope detector aids study of the universe

Center for Nanoscale Materials (CNM) users from Argonne's High Energy Physics and Materials Science divisions helped design and operate part of the South Pole Telescope, a project that aims a large telescope at the night sky to track radiation from the period just after the universe was born. 

Developing and designing the detectors for the camera required expertise from several Argonne facilities and research divisions, including the expertise and capabilities in CNM's Nanofabrication & Devices Group.

In the wake of the Big Bang, all matter was hot, dense particles and light. As the universe aged, it began to spread and cool, and the intense light from that period traveled across space.

The light is still traveling and has a very distinct radiation signature called the cosmic microwave background. 

Mapping the cosmic microwave background can reveal information about dark matter and dark energy, which are thought to make up 95% of the universe.

Dark energy affects the way galaxy clusters form. By comparing the distribution of distant galaxy clusters with the distribution observed nearby, scientists can decode the role dark energy plays in the universe.

The majority of cosmic microwave background radiation has wavelengths of 1-2 mm. These photons are absorbed by water, so a dry, flat and preferably cold space is needed to capture them.

The South Pole is one of only two ideal locations on Earth. The South Pole telescope is more than 30 feet across, and Argonne scientists helped build its camera.

Detectors for the camera were developed and designed with expertise from several Argonne facilities and research divisions.

At the core of the detector technology is a thin—at the nanoscale—superconducting film comprised of Mo/Au bilayer-based heterostructures modified with superconducting (niobium) and normal (gold) metal stripes.

Superconductors can carry an electrical charge perfectly and are highly sensitive to changes in temperature.

When thermal radiation from the cosmic microwave background hits the camera, it heats the material slightly, changing the conductivity of the film.

The energy coming from that particular part of the sky is then recorded.

More information: D. Hanson et al., "Detection of B-Mode Polarization in the Cosmic Microwave Background with Data from the South Pole Telescope," Physical Review Letters, 111, 141301 (2013)

IceCube Detector under Antarctic ice may have seen first cosmic neutrinos

IceCube, the giant experiment buried beneath the South Pole's ice has recorded the first neutrinos ever detected originating outside our solar system, researchers say.

Neutrinos are produced in our atmosphere but the IceCube experiment -- a cubic kilometer of sensitive detectors sunk into the Antarctic ice -- has seen the first "cosmic neutrinos," they said.

IceCube consists of 86 strings, each with 60 sensitive light detectors strung along it like "fairy lights," sunk deep into the ice.

Rare collisions of neutrinos with the nuclei of atoms in the ice produce a brief flash that the detectors can catch.

With more than 5,000 detectors catching the flashes the direction of the neutrinos' arrival on Earth can be determined, the researchers said.

Neutrinos can be produced in the Earth's atmosphere -- IceCube picks up about 100,000 of that variety a year -- but previous attempts to isolate neutrinos created in far-flung cosmic processes had all failed.

However, in April the IceCube research team reported detecting two neutrinos -- nicknamed Bert and Ernie -- with energy levels high enough to suggest a cosmic rather than atmospheric origin.

The team has now reported 26 more events of similar energy that they expect will also be confirmed as cosmic in origin.

Francis Halzen

Detection is just a first step and "of course, there's much more to do," IceCube principle investigator Francis Halzen told reporters.

"It's after you find them that the work starts; these events are very difficult to analyze."

The study results were presented Wednesday at the IceCube Particle Astrophysics Symposium in Madison, Wis.

NASA ISS IV-TEPC Instrument: Tissue-equivalent proportional counter

The Tissue Equivalent Proportional Counter (TEPC), in situ on the ISS, consists of a spectrometer and cylindrical detector with which to measure external radiation doses.

The purpose of the TEPC is to collect a record of the International Space Station (ISS) environment to construct exposure history records for the crew.

Credit: NASA, JPL

Description
The Tissue Equivalent Proportional Counter (TEPC) is a gas proportional counter used to characterize the radiation environment.

TEPC will also provide near real-time measurements to ground personnel during radiation events and make survey measurements in different parts of the ISS for shield verifications.

TEPC collects data as a function of time to measure the dose and estimate the dose equivalent by making spectral measurements of the lineal energy loss of the radiation as it passes through the detector volume.

The omni-directional detector is surrounded by a tissue equivalent plastic and the internal gas (propane) provides an energy deposition response similar to human tissue. The detector gas is at a very low pressure such that the mass of the gas is approximately that of a cell.

The 512 channel spectrometer stores the lineal energy data in energy bins ranging from approximately 25 keV/micron through channels exceeding 1000 keV/micron. The crew is able to read the current level through an electronic display and has the capability to telemeter data to the ground every 10 seconds.

TEPC is a portable piece of equipment, integrated with numerous ports in various modules to support the survey function of the equipment.

TEPC is an automatic micro-dosimetry system. Each TEPC consists of two main components, the spectrometer unit and the detector unit.

The spectrometer unit contains a powerful computer that allows real-time analysis of the data and provides calculations of total dose, total dose equivalent and incremental dose, as a function of linear energy transfer (LET) and time, for penetrating radiation in space.

The detector unit is attached directly to the multi-channel analyzer (MCA) card in the spectrometer.

Different size detectors can be attached to the TEPC depending on the desired task.

The radiation data that is measured can be stored inside the spectrometer unit for later analysis or communicated via RS-232 to a host computer.

The TEPC is calibrated in terms of lineal energy, by exposing it to fission neutrons and 137Cesium sources.

Scientists Develop Hand-Held Brain Injury Detector

The U.S. National Institute of Health has devised an innovative hand-held machine that enables the rapid detection of brain-related injuries like hematomas.

(a) The design of the device and its use scanning over the head in (b) the absence and (c) presence of a hematoma in the field of view—where the green light on the device indicates presence of a hematoma .

The U.S. National Institute of Health has devised an innovative hand-held machine that enables the rapid detection of brain-related injuries like haematoma - a medical condition that occurs when blood vessels are damaged and blood seeps into surrounding tissues, causing significant and dangerous swelling. It is critical therefore that medical authorities detect haematoma as quickly as possible.

It is believed that one of the more practical applications for the finished device could be focused on screening for these injuries before switching to more expensive CT and MRI techniques. The device, of which there is now a prototype, has been created by Jason D. Riley and his team.

The findings of the team were published in the Optical Society's (OSA) open-access journal, Biomedical Optics Express and center on the belief that near-infrared imaging will help in determining the urgency of patient transport and treatment.

According to the researchers, the device is based on the concept of using instrumental motion as a signal in near-infrared imaging rather than treating it as noise. The device depends on a simplified single-source model with a dual separation detector array that uses motion as a signal for detecting changes in blood volume in the hard, outermost membrane that envelops the brain and spinal cord.

Finally, the paper also suggests the use of the device in situations where authorities cannot resort to either CT or MRI imaging facilities, like warzones or accidents.

Software Algorithm can detect Gout on CT Scan

Having gout, a painful inflammation of your joints, usually in the feet or knees is bad enough, but diagnosing it is no bargain either (the test involves a needle stick into the offending joint).

But a new software algorithm used to detect gout via a scanner is promising a much less invasive test. On the scan CT values of uric acid deposits show up in red, while other bone formations and calcium are displayed in blue, according to Siemens which developed the system.

Dark Matter Hunters Construct a New Weapon - Detector

That dark matter has never been found is no deterrent to the physicists who are looking for it.

“Even if we don’t know what dark matter is, we know how it must act,” said Eduardo Abancens, a physicist at Spain’s University of Zaragoza and designer of a prototype dark matter detector.

According to physicists, only around five percent of what makes up the universe can presently be detected. The existence of dark matter is inferred from the behavior of faraway galaxies, which move in ways that can only be explained by a gravitational pull caused by more mass than can be seen. They estimate dark matter represents around 20 percent of the universe, with the other 75 percent made up of dark energy, a repulsive force that is causing the universe to expand at an ever-quickening pace.

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