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  • richardmitnick 2:41 pm on May 29, 2019 Permalink | Reply
    Tags: , , , , , Infrared vision, Instrumentation,   

    Fom James Webb Space Telescope: “A New View of Exoplanets With NASA’s Upcoming Webb Telescope” 

    NASA Webb Header

    NASA Webb Telescope
    NASA/ESA/CSA

    Fom James Webb Space Telescope

    May 29, 2019

    Contact:
    Ann Jenkins /
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4488 /
    jenkins@stsci.edu

    Christine Pulliam
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4366
    cpulliam@stsci.edu

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    About This Image

    One of the targets Webb will study is the well-known, giant ring of dust and planetesimals orbiting a young star called HR 4796A. This Hubble Space Telescope photo shows a vast, complex dust structure, about 150 billion miles across, enveloping the young star HR 4796A. (The light from HR 4796A and its binary companion, HR 4796B, have been blocked to reveal the much dimmer dust structure.) A bright, narrow inner ring of dust encircling the star may have been corralled by the gravitational pull of an unseen giant planet. Credits: NASA/ESA and G. Schneider (University of Arizona)

    How Do We Find Exoplanets?

    The James Webb Space Telescope will open a new window on exoplanets, planets around other suns. With its keen infrared vision, Webb will observe them in wavelengths where they have never been studied before. One of the telescope’s first observation programs is to look at young, newly formed exoplanets and the systems they inhabit. Scientists will use all four of Webb’s instruments to observe three targets: A recently discovered exoplanet; an object that is either an exoplanet or a brown dwarf; and a well-studied ring of dust and planetesimals orbiting a young star. Webb will be vital for understanding how these objects form, and what these systems are like. These observations are part of a program that allows the astronomical community to quickly learn how best to use Webb’s capabilities, while also yielding robust science.

    While we now know of thousands of exoplanets — planets around other stars — the vast majority of our knowledge is indirect. That is, scientists have not actually taken many pictures of exoplanets, and because of the limits of current technology, we can only see these worlds as points of light. However, the number of exoplanets that have been directly imaged is growing over time. When NASA’s James Webb Space Telescope launches in 2021, it will open a new window on these exoplanets, observing them in wavelengths at which they have never been seen before and gaining new insights about their nature.

    Exoplanets are close to much brighter stars, so their light is generally overwhelmed by the light of the host stars. Astronomers usually find an exoplanet by inferring its presence based on the dimming of its host star’s light as the planet passes in front of the star—an event called a “transit.” Sometimes a planet tugs on its star, causing the star to wobble slightly.

    In a few cases, scientists have captured pictures of exoplanets by using instruments called coronagraphs. These devices block the glare of the star in much the same way you might use your hand to block the light of the Sun. However, finding exoplanets with this technique has proven to be very difficult. All that will change with the sensitivity of Webb. Its onboard coronagraphs will allow scientists to view exoplanets at infrared wavelengths they’ve never seen them in before.

    Webb’s Unique Capabilities

    Coronagraphs have something important in common with eclipses. During an eclipse, the Moon blocks the light of the Sun, allowing us to view stars that would normally be overwhelmed by the Sun’s glare. Astronomers took advantage of this during the 1919 eclipse, 100 years ago on May 29, in order to test Albert Einstein’s theory of general relativity. Similarly, a coronagraph acts as an “artificial eclipse” to block the light from a star, allowing planets that would otherwise be lost in the star’s glare to be seen.

    “Most of the planets that we have detected so far are roughly 10,000 to 1 million times fainter than their host star,” explained Sasha Hinkley of the University of Exeter. Hinkley is the principal investigator on one of Webb’s first observation programs to study exoplanets and exoplanetary systems.

    “There is, no doubt, a population of planets that are fainter than that, that have higher contrast ratios, and are possibly farther out from their stars,” Hinkley said. “With Webb, we will be able to see planets that are more like 10 million, or optimistically, 100 million times fainter.” To observe their targets, the team will use high-contrast imaging, which discerns this large difference in brightness between the planet and the star.

    Webb will have the capability of observing its targets in the mid-infrared, which is invisible to the human eye, but with sensitivity that is vastly superior to any other observatory ever built. This means that Webb will be sensitive to a class of planet not yet detected. Specifically, Saturn-like planets at very wide orbital separations from their host star may be within reach of Webb.

    “Our program is looking at young, newly formed planets and the systems they inhabit,” explained co-principal investigator Beth Biller of the University of Edinburgh. “Webb is going to allow us to do this in much more detail and at wavelengths we’ve never explored before. So it’s going to be vital for understanding how these objects form, and what these systems are like.”

    Testing the Waters

    The team’s observations will be part of the Director’s Discretionary-Early Release Science program, which provides time to selected projects early in the telescope’s mission. This program allows the astronomical community to quickly learn how best to use Webb’s capabilities, while also yielding robust science.

    “With our ERS program, we will really be ‘testing the waters’ to get an understanding of how Webb performs,” said Hinkley. “We really need the best understanding of the instruments, of the stability, of the most effective way to post-process the data. Our observations are going to tell our community the most efficient way to use Webb.”

    The Targets

    Hinkley’s team will use all four of Webb’s instruments to observe three targets: A recently discovered exoplanet; an object that is either an exoplanet or a brown dwarf; and a well-studied ring of dust and planetesimals orbiting a young star.

    Exoplanet HIP 65426b: This newly discovered, directly imaged exoplanet has a mass between six and 12 times that of Jupiter and is orbiting a star that is hotter than and about twice as massive as our Sun.

    Direct imaging-This false-color composite image traces the motion of the planet Fomalhaut b, a world captured by direct imaging. Credit: NASA, ESA, and P. Kalas (University of California, Berkeley and SETI Institute

    The exoplanet is roughly 92 times farther from its star than Earth is from the Sun. The wide separation of this young planet from its star means that the team’s observations will be much less affected by the bright glare of the host star. Hinkley and his team plan to use Webb’s full suite of coronagraphs to view this target.

    Planetary-mass companion VHS 1256b: An object somewhere around the planet/brown dwarf boundary, VHS 1256b also is widely separated from its red dwarf host star—about 100 times the distance that the Earth is from the Sun. Because of its wide separation, observations of this object are much less likely to be affected by unwanted light from the host star. In addition to high-contrast imaging, the team expects to get one of the first “uncorrupted” spectra of a planet-like body at wavelengths where these objects have never before been studied.

    Circumstellar debris disk: For more than 20 years, scientists have been studying a ring of dust and planetesimals orbiting a young star called HR 4796A, which is about twice as massive as our own Sun. Astronomers think that most planetary systems probably looked a lot like HR 4796A and its debris ring at their earliest ages, making this a particularly interesting target to study. The team will use the high-contrast imaging of Webb’s coronagraphs to view the disk in different wavelengths. Their goal is to see if the structures of the disk look different from wavelength to wavelength.

    Planning the Program

    To plan this Early Release Science program, Hinkley asked as many members of the astronomical community as possible the simple question: If you want to plan a survey to search for exoplanets, what are the questions that you need the answers to for planning your surveys?

    “What we came up with was a set of observations that we think is going to answer those questions. We are going to tell the community that this is the way Webb performs in this mode, this is the kind of sensitivity we get, and this is the kind of contrast we achieve. And we need to rapidly turn that around and inform the community so that they can prepare their proposals really, really quickly.”

    The team is excited to view their targets in wavelengths never before detected, and to share their knowledge. According to Biller, “We could see years ago that for some of the planets we’ve already discovered, Webb would be really transformational.”

    The James Webb Space Telescope will be the world’s premier space science observatory when it launches in 2021. Webb will solve mysteries in our solar system, look beyond to distant worlds around other stars, and probe the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and the Canadian Space Agency.

    See the full article here .

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    The James Webb Space Telescope will be a large infrared telescope with a 6.5-meter primary mirror. Launch is planned for later in the decade.

    Webb telescope will be the premier observatory of the next decade, serving thousands of astronomers worldwide. It will study every phase in the history of our Universe, ranging from the first luminous glows after the Big Bang, to the formation of solar systems capable of supporting life on planets like Earth, to the evolution of our own Solar System.

    Webb telescope was formerly known as the “Next Generation Space Telescope” (NGST); it was renamed in Sept. 2002 after a former NASA administrator, James Webb.

    Webb is an international collaboration between NASA, the European Space Agency (ESA), and the Canadian Space Agency (CSA). The NASA Goddard Space Flight Center is managing the development effort. The main industrial partner is Northrop Grumman; the Space Telescope Science Institute will operate Webb after launch.

    Several innovative technologies have been developed for Webb. These include a folding, segmented primary mirror, adjusted to shape after launch; ultra-lightweight beryllium optics; detectors able to record extremely weak signals, microshutters that enable programmable object selection for the spectrograph; and a cryocooler for cooling the mid-IR detectors to 7K.

    There will be four science instruments on Webb: the Near InfraRed Camera (NIRCam), the Near InfraRed Spectrograph (NIRspec), the Mid-InfraRed Instrument (MIRI), and the Fine Guidance Sensor/ Near InfraRed Imager and Slitless Spectrograph (FGS-NIRISS). Webb’s instruments will be designed to work primarily in the infrared range of the electromagnetic spectrum, with some capability in the visible range. It will be sensitive to light from 0.6 to 28 micrometers in wavelength.

    NASA Webb NIRCam

    NASA Webb NIRspec

    NASA Webb MIRI

    CSA Webb Fine Guidance Sensor-Near InfraRed Imager and Slitless Spectrograph FGS/NIRISS


    Webb has four main science themes: The End of the Dark Ages: First Light and Reionization, The Assembly of Galaxies, The Birth of Stars and Protoplanetary Systems, and Planetary Systems and the Origins of Life.

    Launch is scheduled for later in the decade on an Ariane 5 rocket. The launch will be from Arianespace’s ELA-3 launch complex at European Spaceport located near Kourou, French Guiana. Webb will be located at the second Lagrange point, about a million miles from the Earth.

    NASA image

    ESA50 Logo large

    Canadian Space Agency

     
  • richardmitnick 1:17 pm on October 26, 2018 Permalink | Reply
    Tags: , , , , , Gert Finger known as one of the “fathers” of ESO detectors, Instrumentation   

    From ESOblog: “A Lifetime at ESO” 

    ESO 50 Large

    From ESOblog

    26 October 2018

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    Gert Finger

    The detectors used on ESO’s telescopes are among the best in the world, and without them, ESO would not be able to provide the astronomical community with the amazing facilities that it is known for. The development of these detectors is only possible with many years of research and hard work. And here at ESO, it is common knowledge that a lot of this work can be attributed to Gert Finger, known as one of the “fathers” of ESO detectors. In this week’s blog post, Gert shares insights into his career and tells us more about what makes ESO’s detectors so special.

    Q: Firstly could you tell us how you became involved in ESO? What was your path to working here?

    A: After obtaining my PhD from the Swiss Institute of Technology in Zurich, I was uncertain where to go. I had received an offer from the renowned Bell Labs in the US, but the technical specialist who had assisted me during my PhD had also found a newspaper announcement for a technical position at ESO in Munich. My son said, “Munich, Munich, Munich!” because he wanted me to stay close to him in my home in Austria. I also liked the fact that ESO has never been involved in any military projects. At the time ESO was building the IRSPEC instrument, a spectrometer for the ESO 3.6-metre telescope, which I thought would be really interesting to work on. So because of all of these reasons my final choice was to apply to ESO.

    ESO IRSPEC now decommissioned

    Q: And you’ve worked in the ESO technology department ever since! What kind of roles did you have there?

    A: Initially, I was working on the calibration and grating of IRSPEC, but once this instrument was finished I started working on a few other instruments. Slowly but surely I moved more into the detector field, which was challenging as I didn’t start out as a detector specialist at all. Throughout my time at ESO I have worked on almost all the infrared detectors that have gone onto the ESO instrumentation.

    Detectors are incredibly important because by converting photons of light into an electrical signal, they achieve the final collection of light that allows us to observe the Universe. When I first joined ESO there were two separate detector groups — one working on detectors that collected optical light and the other focused on infrared light. Later on, the two groups merged and eventually I was appointed Head of the Detector Department, which was my position until the end of my career. Upon retirement, I became an emeritus physicist at ESO. So yes indeed, I have spent a lot of my life here at ESO!

    Q: Within ESO you are known as the “go-to-guy” for information about the ESO detectors. Can you tell us more about them?

    IRAC1 on the ESO 2.2m telescope at LaSilla

    A: The first astronomical research was carried out using the human eye as a detector of light. Then in the 19th century astronomers started using photography to record astronomical images. Nowadays we use electronic detectors, which convert light into electrons to produce images and spectra. Detectors are found in all the instruments of ESO’s telescopes and almost all of these have been developed in house. One of ESO’s areas of expertise is in detector controllers which operate the detectors. We have created our own controller, the NGC controller, which can work with all of the detector systems. This is a big advantage over other observatories that use lots of different controllers from different companies — a nightmare regarding maintenance!

    Q: Is there anything you’ve worked on during your time at ESO that you are particularly proud of?

    A: I am really proud of initiating electron avalanche photodiode (eAPD) detector technology.

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    Avalanche photodiode

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    A 320 x 256 pixel eAPD array as used in the GRAVITY instrument. This detector has revolutionised ground-based astronomy.

    ESO GRAVITY insrument on The VLTI, interferometric instrument operating in the K band, between 2.0 and 2.4 μm. It combines 4 telescope beams and is designed to peform both interferometric imaging and astrometry by phase referencing. Credit: MPE/GRAVITY team

    When a photon enters an eAPD, it creates an electron which is accelerated to generate an avalanche of fast-moving electrons that are more easily detected than a single electron. eAPDs outperform any other high-speed sensor technology in terms of sensitivity and they are now used worldwide! Five eAPDs are installed on the GRAVITY instrument in the Very Large Telescope Interferometer (VLTI), allowing it to peer into the galactic centre and precisely measure the positions and movements of stars. GRAVITY has even helped reveal the effects predicted by Einstein’s general relativity on the motion of a star passing through the extreme gravitational field near the black hole at the Milky Way’s centre. And it has led to more amazing discoveries soon to be announced.

    The Max Planck Institute for Extraterrestrial Physics (MPE) really understood what could be gained with this technology so I would like to thank them for all their support. The company manufacturing the arrays of eAPDs is called LEONARDO, and I would like to thank Adrian Russell, Director of Programmes at ESO for funding several production runs at LEONARDO. It is thanks to a collaboration between several partners that we have been able to develop this completely new technology.

    Q: How many years have you worked at ESO, and how has ESO changed during your time here?

    A: I came to ESO in 1983 and have acquired expertise over time. To avoid becoming someone who knows more and more about less and less until he knows everything about nothing, it is important to communicate with other specialists. In my opinion, what is great about ESO is that there are people who are truly experts in their field, who love their job and who are very competent. There is a lot of support and people are always interested in what you are doing. There has obviously been a lot of restructuring during my time here but these people and their expertise are the backbone of ESO and it’s very nice that this has survived all the changes.

    Q: You’ve retired now. Many people would relish the freedom from work but you’ve decided to remain heavily involved in ESO. Why?

    A: To be honest, the main reason I chose to continue was for the eAPD technology. It had just been implemented in GRAVITY and I saw that it could be developed further — not only for high-speed sensors that correct the twinkling of stars as their light passes through Earth’s atmosphere, but also for large science detectors. I realised this technology could mark the next step in sensitivity, since many characteristics of eAPD arrays are equal to, or better than, the characteristics of conventional science detectors currently in use.

    GRAVITY is home to Mark#3 detectors, but we’ve recently developed version Mark#14, which shows just how far this technology has come over the last few years! GRAVITY eAPDs collect light with wavelengths between 1.3 and 2.5 microns, but the current eAPD technology is sensitive between 0.8 and 2.5 microns. The VLT’s MUSE instrument needs exactly such a sensor to be able to see more astronomical objects.

    Q: What has been your favourite moment working at ESO?

    A: It’s hard to choose just one moment but a special memory that stands out is when we got IRAC 1 working. This is a cryogenic infrared camera which hosted several generations of infrared detector arrays. Another nice moment was when the ISAAC instrument went to the VLT.

    ESO ISAAC at the Nasmyth A focus of UT3 on the VLT

    At that time, there was no hotel for astronomers to stay in; we lived in containers but it was someone’s birthday so a guitar came out and a party got started. I’m so grateful that there are very competent people to collaborate with at ESO and when I come to them they are always open and we have fun working together.

    Q: How do you feel about being known as one of the “fathers” of ESO detectors?

    A: What can I say… it’s true that I started with one-pixel detectors and just before I retired I was working with some 4096 x 4096-pixel infrared detectors! I am extremely lucky and happy that my professional career spanned the time during which detector technology developed very, very quickly.

    Q: Is there anything else you would like to mention about your time at ESO?

    A: I believe that technology development should be prioritised because it really helps the organisation and astronomy as a whole. ESO is a world-leader in this field and it should make sure it stays there. I also think that it’s incredibly important to make ESO technology available for telescopes belonging to other institutes, and I have always worked hard to ensure that this is the case.

    The most important things during my professional life were curiosity, inquisitiveness, communication with experts working in other fields and collaboration with instrument consortia and detector manufacturers.

    See the full article here .


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    ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre European Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

    ESO LaSilla
    ESO/Cerro LaSilla 600 km north of Santiago de Chile at an altitude of 2400 metres.

    ESO VLT 4 lasers on Yepun


    ESO Vista Telescope
    ESO/Vista Telescope at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level.

    ESO NTT
    ESO/NTT at Cerro LaSilla 600 km north of Santiago de Chile at an altitude of 2400 metres.

    ESO VLT Survey telescope
    VLT Survey Telescope at Cerro Paranal with an elevation of 2,635 metres (8,645 ft) above sea level.

    ALMA Array
    ALMA on the Chajnantor plateau at 5,000 metres.

    ESO/E-ELT,to be on top of Cerro Armazones in the Atacama Desert of northern Chile. located at the summit of the mountain at an altitude of 3,060 metres (10,040 ft).


    ESO APEX
    APEX Atacama Pathfinder 5,100 meters above sea level, at the Llano de Chajnantor Observatory in the Atacama desert.

    Leiden MASCARA instrument, La Silla, located in the southern Atacama Desert 600 kilometres (370 mi) north of Santiago de Chile at an altitude of 2,400 metres (7,900 ft)

    Leiden MASCARA cabinet at ESO Cerro la Silla located in the southern Atacama Desert 600 kilometres (370 mi) north of Santiago de Chile at an altitude of 2,400 metres (7,900 ft)

    ESO Next Generation Transit Survey at Cerro Paranel, 2,635 metres (8,645 ft) above sea level

    SPECULOOS four 1m-diameter robotic telescopes 2016 in the ESO Paranal Observatory, 2,635 metres (8,645 ft) above sea level

    ESO TAROT telescope at Paranal, 2,635 metres (8,645 ft) above sea level

    ESO ExTrA telescopes at Cerro LaSilla at an altitude of 2400 metres

     
  • richardmitnick 2:04 pm on March 11, 2014 Permalink | Reply
    Tags: , , , Instrumentation,   

    From Symmetry: “The Instrumentation Frontier” 

    March 11, 2014
    Paul Preuss

    Devices designed for science open both the wonders of the cosmos and new possibilities in everyday life.

    Half a millennium ago, Dutch spectacle-makers put lenses together in new ways and invented the telescope and the microscope. Novel instruments have been the key to scientific discovery throughout history.
    In particle physics, new technologies brought the field into the electronic era, enabling the discovery of the top quark and the Higgs boson, and contributing to establishing the Standard Model of fundamental particles and forces.

    sm
    The Standard Model of elementary particles, with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth.

    “Technologies are transformative,” says physicist Marcel Demarteau, a senior scientist at Argonne National Laboratory. “New technologies have made it possible to measure the universe at the dawn of time, probe the dark sector, study the asymmetry between matter and anti-matter, and track down the secrets of the elusive neutrino.”

    Whether the search is for supersymmetric particles or distant quasars, detectors are the sine qua non of particle physics and cosmology. Particle physics has pushed detector technology forward for decades, and new materials and innovative industrial techniques offer the potential to do so again. New technologies can find their way into daily life as well.

    Thick chips for searching the skies

    Twenty years ago, scientists assumed the pull of gravity was slowing the universe’s expansion. The international Supernova Cosmology Project, based at Lawrence Berkeley National Laboratory, set out to measure how the universe was changing by observing Type Ia supernovae, exploding stars whose consistent brightness makes them dependable standard candles for establishing cosmic distances.

    By comparing Type Ia distances and redshifts—a direct measure of expansion, which stretches the light traveling from the supernovae to longer wavelengths—the SCP team and the rival High-Z Supernova Search Team discovered, to their astonishment, that the universe is actually expanding at an accelerating rate.

    This was the first evidence that dark energy is pushing the universe apart, but finding it wasn’t easy: The most advanced detectors of the day performed poorly with highly redshifted light.

    Saul Perlmutter, who heads the SCP, recalls that in 1994, “we were having problems with the red sensitivity and internal reflections at red wavelengths in existing astronomical CCDs.”

    sp
    Nobel laureate Dr. Saul Perlmutter

    At the time, CCDs—the charge-coupled devices found in digital cameras—were the cutting-edge technology for replacing photographic plates in astronomy. CCDs capture photons and convert them to electrical signals. But typical astronomical CCDs have to be shaved to a tissue-thin 20 millionths of a meter to allow charge carriers to reach the circuitry on the other side of the chip.

    While that works great for blue light, it’s bad news for red and infrared light, which are long-wavelength and can sail right through a thin chip; what doesn’t get through bounces back and forth, causing interference fringes. Not only did thin astronomical CCDs have problems with red light, they were expensive. So many were damaged during thinning that the survivors were worth more than 50,000 dollars each.

    Existing CCDs were a weak point for the SCP and high-redshift astrophysics generally. Over lunch in the Berkeley Lab cafeteria in 1994, Perlmutter explained the difficulties to physicist David Nygren, a man Demarteau calls “the best instrumentalist in the field.”

    Nygren suggested that Perlmutter talk with an electronics engineer named Steve Holland. Holland had just developed an advanced silicon-based detector for another project, the ill-fated Superconducting Super Collider, which was planned but never constructed. Like most silicon detectors for accelerators, it was a rugged chip about the thickness of a postcard.

    Off and running, Holland and his colleagues morphed the particle-catcher into a light catcher. A thin window on the light-collecting side doubled as an electrode, creating voltage that guided blue-light charges straight through to the chip’s electronics, while the chip’s thickness caught long-wavelength photons and eliminated fringe-producing reflections.

    Manufacturing processes took time to perfect, so the supernova teams had to discover dark energy without the advanced CCD. Nevertheless its impact on cosmology has been remarkable. The Berkeley Lab design is a key part of several leading modern experiments that probe the nature of dark energy: the third Sloan Digital Sky Survey’s Baryon Oscillation Spectroscopic Survey; the Hyper Suprime-Cam on the 8.2-meter Subaru Telescope; and the innovative Dark Energy Camera that powers the Dark Energy Survey.

    cam
    Hyper Suprime-Cam

    Subaru Telescope
    Subaru on Mauna Kea, Hawaii

    Dark Energy Camera
    DeCAM

    “The red sensitivity of the CCDs was one of the critical new features that made DECam worth doing,” says Brenna Flaugher, head of Fermilab’s Astrophysics Department, who led the development of Dark Energy Camera.

    The advanced CCD also contributed to significant progress in medical imaging. Its photodiode component not only captures long-wavelength red light but other radiation as well. Early on, the technology was licensed for cameras that diagnose heart disease by the Digirad Corporation, one of the top players in the world’s $2 billion nuclear imaging market.

    ccd
    The Berkeley Lab CCD is known for its high sensitivity to light, particularly long-wavelength red light.
    Courtesy of: Berkeley Lab

    A multiple-purpose layer cake

    Perlmutter and Holland’s story is one of many. Over and over in particle physics, researchers see a need for new kinds of instrumentation and find unique solutions that go on to revolutionize the field—and, often, other fields as well.

    In 2007, Ray Yarema, then head of the Electrical Engineering Department in Fermilab’s Particle Physics Division, saw a coming wave of collider experiments that would pose critical technical problems. As particle accelerators produced collision events more efficiently, experimentalists would require wide arrays of trackers to deal with tsunamis of data.

    The biggest challenges would arise closest to where the beams collided. A new generation of detectors was needed to combine pixel arrays, which determine where particles strike, with readout electronics. They had to have higher resolution, quicker processing and better radiation hardness than anything then in the works.

    Yarema argued that a solution was already at hand in the form of three-dimensional integrated circuits, or 3D_ICs, developed by industry. These could “do all kinds of neat calculations [and] deliver nearly instantaneous processing with far less power,” says Demarteau, who was then working at Fermilab. The task was to integrate pixel sensors, which register where particles strike, into a new kind of 3D IC.

    Fermilab organized an international consortium of a dozen physics laboratories to produce a demonstration 3D pixel-readout chip. They chose Tezzaron Semiconductor, a leader in the 3D field, as an industrial partner.

    “We were designing 3D chips as early as 2004, and we’d already gotten to the show-stoppers and fixed them,” says Gretchen Patti, a Tezzaron technical staff member and the company’s spokesperson. Although their specialty was memory chips, Patti says the prospect of working with a national laboratory was exciting. “The great thing about Fermilab is that they are pushing the boundaries of what 3D can do. Sensors are a wonderful application for 3D.”

    Together, the laboratory consortium overcame design and manufacturing challenges to develop a highly successful 3D chip. Each problem that’s overcome opens the way for new applications of 3D integrated circuitry for science and the consumer.

    Grzegorz Deptuch, who has led Fermilab’s Pixel Design Group since Yarema’s retirement, says that for many instruments, the ability to make a 3D chip with any combination of sensors, processors and memory, using both analog and digital elements, “is the right answer.”

    As for computing power, “one can imagine storing a terabyte of information on something the size of a postage stamp,” says Demarteau. “Think about putting that in your next smart phone.” This potential power and flexibility account for a 3D IC market estimated at $3 billion, climbing toward $7.5 billion by 2019.

    chip
    A Tezzaron-Fermilab 3D chip.
    Photo by: Fred Ullrich, Fermilab

    Shaping the light

    Today, instrumentation development is more important than ever. When even small experiments can cost millions, “time and cost mean the projects have to succeed, so there’s little risk-taking,” Demarteau says. Yet, at the same time, “there has to be investment in instrumentation with a healthy portfolio of risk.”

    Early in 2012, Waruna Fernando, then a postdoc at Argonne’s Center for Nanoscale Materials, called Demarteau’s attention to an article in the journal Nano Letters: A group at the University of California, Berkeley, described using graphene—single sheets of carbon atoms—to manipulate light.

    Demarteau recalls, “Waruna’s first thought was that we could make a new kind of optical modulator,” a device that can shape the frequency, amplitude, and other properties of the light signal, including how many channels a single fiber can carry. “It was an intriguing idea, and we wondered what else we could do with it—perhaps use it for developing a new kind of particle detector.”

    The worth of any detector increasingly depends on fast, smart transmission of its data. “The limitation on signal transfer in an optical fiber is how many bits per second you can push through it,” says Demarteau. “Essentially you have to turn the light on and off really fast.”

    His team is developing two kinds of modulator. Their initial effort—which he calls a “crude concept”—lays bare the fiber’s cladding to expose the glass core, then wraps it with two sheets of graphene. The double layer interacts with the evanescent electromagnetic field generated by lightwaves moving through the core; electrodes attached to the graphene tune the voltage. Demarteau explains, “Graphene kills the light, but applying a voltage to the graphene makes it transparent.”

    Crude, maybe, but this kind of modulator is expected to couple efficiently to the optical signal, consuming little power at minimal cost. Demarteau’s group has already demonstrated proof of the principle.

    A more sophisticated design would create ring waveguides—structures that steer light—each tailored to resonate at a specific wavelength. The resonant wavelength travels around the ring, “leaking” to adjacent silicon waveguides, which read out the signal. The technique could filter out unwanted frequencies in astronomical observations, for example. Whether made of graphene or other materials, ring waveguides could be tuned to different frequencies, enabling a single fiber to carry hundreds of channels.

    “This is really pie in the sky,” Demarteau says, “but theoretically we could make a modulator that operates at 400 or 500 gigabits per second per channel, for high-speed data transmission totalling trillions of bits per second. With that kind of capacity, your detector could stream any amount of data.”

    Applications in the “real world” would be tremendous, he adds, “from streaming many millions of phone calls over a single fiber, to providing near instantaneous access to massive amounts of data anywhere in the world.”

    graphene
    Graphene, which has a hexagonal structure, is a promising material for high-speed data transmission.
    Courtesy of: Argonne National Laboratory

    Into the future

    The implications of any new technology, like any scientific result, are sometimes more exciting than what can be imagined in advance—and almost always different. After inventing the radio in 1887 to prove the existence of electromagnetic waves, Heinrich Hertz explained its other applications with the dismissive phrase, “it’s of no use whatsoever.” Ten years later, J.J. Thompson used a cathode ray tube to determine that electrons were discrete particles, a discovery that was not of much interest to people outside of physics—until the advent of telephones, radios, TVs, computers, smart phones… with no end in sight.

    Today, scientists are more alert to the possibilities. From proven successes to pie-in-the-sky, the foremost goal of instrument designers is to extend the reach of science. But they also know that what’s transformative for science can be transformative for society. So they keep a sharp eye open for the gadgets that could trigger tomorrow’s telecommunications, electronics or medical diagnostics.

    “Innovation and improvement in the quality of life go hand in hand,” Demarteau says. “Investment in R&D for new technologies in particle physics, combined with advances in other areas of science, will not only open the wonders of the cosmos to us all but improve the quality of our lives, as it has in the past.”

    See the full article here.

    Symmetry is a joint Fermilab/SLAC publication.



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