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  • richardmitnick 3:30 pm on May 25, 2021 Permalink | Reply
    Tags: "Candid cosmos- eROSITA cameras set a benchmark for astronomical imaging", , , , eROSITA is aboard the (RU) Spectrum-Roentgen-Gamma (SRG) satellite., eROSITA is expected to revolutionize our understanding of the evolution of supermassive black holes., eROSITA is not one telescope but an array of seven identical co-aligned telescopes with each one composed of a mirror system and a focal-plane camera., Redshifts greater than 1 is faster than the speed of light(?)., SPIE, The eROSITA has been designed to study the large-scale structure of the universe and test cosmological models including Dark Energy by detecting galaxy clusters with redshifts greater than 1.,   

    From SPIE: “Candid cosmos- eROSITA cameras set a benchmark for astronomical imaging” 


    From SPIE

    24 May 2021

    An overview and performance assessment of the seven cameras of eROSITA, a space x-ray telescope launched in 2019.

    Recently, the eROSITA (extended Roentgen Survey with an Imaging Telescope Array) x-ray telescope, an instrument developed by a team of scientists at MPG Institute for extraterrestrial Physics [MPG Institut für Extraterrestrische Physik] (MPE) (DE), has gained attention among astronomers. The instrument performs an all-sky survey in the x-ray energy band of 0.2-8 kilo electron volts aboard the (RU) Spectrum-Roentgen-Gamma (SRG) satellite that was launched in 2019 from the Baikonur cosmodrome in Kazakhstan.

    “The eROSITA has been designed to study the large-scale structure of the universe and test cosmological models including Dark Energy by detecting galaxy clusters with redshifts greater than 1, corresponding to a cosmological expansion faster than the speed of light (?),” said Dr. Norbert Meidinger from MPE, a part of the team that developed the instrument. “We expect eROSITA to revolutionize our understanding of the evolution of supermassive black holes.” The details of the developmental work have been published in SPIE’s Journal of Astronomical Telescopes, Instruments, and Systems (JATIS).

    eROSITA is not one telescope but an array of seven identical co-aligned telescopes with each one composed of a mirror system and a focal-plane camera. The camera assembly, in turn, consists of the camera head, camera electronics, and filter wheel. The camera head is made up of the detector and its housing, a proton shield, and a heat pipe for detector cooling. The camera electronics include supply, control, and data acquisition electronics for detector operation. The filter wheel is mounted above the camera head and has four positions including an optical and UV blocking filter to reduce signal noise, a radioactive x-ray source for calibration, and a closed position that allows instrumental background measurements.

    “It’s exciting to read about these x-ray cameras that are in orbit and enabling a broad set of scientific investigations on a major astrophysics mission,” says Megan Eckart of Lawrence Livermore National Laboratory, (US), who is the deputy editor of JATIS. “Dr. Meidinger and his team provide a clear description of the hardware development and ground testing, and wrap up the paper with a treat: first-light images from eROSITA and an assessment of onboard performance. Astrophysicists around the world will analyze data from these cameras for years to come.”

    The eROSITA telescope is well on its way to becoming a game changer for x-ray astronomy.

    First light of the eROSITA X-ray telescope in space.

    See the full article here .


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  • richardmitnick 4:58 pm on March 2, 2019 Permalink | Reply
    Tags: , , , , , , , So many recent successes for NASA ansd ESA it is astounding great science, SPIE   

    From SPIE: “Lasers make the grade in Earth observation and space exploration” 


    From SPIE

    1 March 2019
    Mike Hatcher

    Astronomers, weather forecasters, and Earth scientists are among those now benefiting from the application of solid-state lasers in space.

    Laser equipment for cooling atoms in space arrived at the International Space Station in July 2018 on board a Cygnus supply vehicle – seen here being collected by robotic arm. Photo: NASA.

    Even by stellar historic standards, it has been a remarkable few months for space probes and their on-board optical instrumentation. Late 2018 saw the erstwhile Voyager 2 probe – complete with interferometer, ultraviolet spectrometer, photo-polarimeter, and dual-camera imaging science system – finally leave the solar system.

    NASA/Voyager 2

    We’ve also witnessed some extraordinary imagery and data acquisition carried out by missions such as the Parker Solar Probe, the close encounter between OSIRIS-REx and asteroid Bennu, and ozone monitoring by the Earth-observing Sentinel-5P satellite.

    NASA Parker Solar Probe Plus named to honor Pioneering Physicist Eugene Parker

    NASA OSIRIS-REx Spacecraft

    ESA Copernicus Sentinel-5P

    Just weeks before Photonics West opened its doors the imaging instruments on NASA’s New Horizons mission captured the unusual “lumpy snowman” form of Ultima Thule, and a couple of days later China’s Chang’e 4 probe touched down on the far side of the Moon.

    NASA/New Horizons spacecraft

    China’s Chang’e 4 moon lander

    Recent months have also seen the launch of the Bepi Colombo mission to Mercury, its payload featuring a laser altimeter and an ultraviolet (UV) spectroscopy probe, a laser-cooled atom experiment delivered to the International Space Station (ISS), and the deployment of laser terminals to quickly transmit huge data sets back to Earth from imaging satellites.

    ESA-JAXA BepiColombo

    In terms of photonics equipment, perhaps most satisfying of all has been the recent arrival of a couple of solid-state lasers on board Earth-orbiting spacecraft. Last August, the European Space Agency (ESA) finally launched its wind-monitoring Aeolus satellite.

    ESA ADM-Aeolus satellite

    The first wind lidar instrument in space, it is based around a UV laser and is set to provide far more accurate and detailed monitoring of wind speeds than was previously possible.

    Attempts to understand and forecast the wind date back as far as Aristotle in the 4th century BC. Today, wind profiles sampled down through the atmosphere are needed for accurate medium- to long-term weather forecasting, and are critical for modelling climate change. But until Aeolus, this information was not available from direct measurement: the best equivalent came from ground sensors and balloon monitors giving localized point measurements, followed by extrapolation through cloud tracking or computer simulations. Aeolus being in orbit changes that, and for the first time global wind fields can be mapped directly, in three dimensions.

    Challenging development

    “Using revolutionary laser technology, Aeolus will measure winds around the globe and play a key role in our quest to better understand the workings of our atmosphere,” announced ESA following the launch of the 1.4-tonne satellite aboard a Vega rocket last year. “Importantly, this novel mission will also improve weather forecasting.”

    But the mission has also proved to be one of ESA’s most technologically demanding. Problems with the “Aladin” UV laser, in particular the damage caused to its system optics over an extended operating period, had delayed the original launch schedule by more than a decade. Thanks in part to technical breakthroughs made with a similar source – the green laser at the heart of NASA’s similarly delayed ICESat-2 mission – the Aeolus mission now looks set for major success.

    NASA ICESat 2

    A couple of weeks after launch, Aeolus sent back its first data, and in November Errico Armandillo, the retired head of ESA’s optoelectronics section, reflected on the development. “Today Aeolus is returning more wind data than all ground-based measuring systems put together,” he remarked. “But it took the sustained efforts of ESA labs and technical experts – in close cooperation with the Aeolus team – to make it fly.”

    In fact ESA set up two new laboratories to solve its laser issues. It called in additional support from the German Aerospace Center to produce entirely new technical standards, which are now being applied to all subsequent laser missions.

    “The commercial space industry by itself could not have gone to the lengths we took,” Armandillo pointed out.

    The idea of flying a wind-surveying lidar in orbit was nothing new. In fact it had been explored as long ago as the early 1980s, considered at one time for the ISS. And in fact the technology developed back then is now used to help guide rendezvous and docking operations with ISS-supplying cargo spacecraft.

    Initially a high-energy carbon dioxide gas laser was earmarked for the lidar role, before the mid- 1990s development of space-worthy pump laser diodes opened the door to far more compact solid-state designs. The Aeolus mission was pencilled in for a launch some time after 2000.

    The Aladin laser is at the heart of the Aeolus satellite

    Based around a conventional Nd:YAG solid-state laser crystal, the UV wavelength selected is seen as essential for achieving the high level of back-scatter from both molecular and aerosol components to provide reliable lidar signals. But ESA saw the first signs of trouble in NASA’s ICESat mission, which was using a UV laser to map ice. Around the same time, ground tests on Aladin began to show laser-induced contamination of optics.

    The key problem was then identified: out-gassing of organic molecules from Aladin’s laser equipment was accumulating on system lenses, before being carbonized by the high-energy UV laser pulses. As they grew, those deposits further absorbed the laser’s heat, distorting and darkening the optical components.

    It meant that the original performance of the UV laser within Aladin was nowhere close to requirements. ESA says that when it ran a prototype version of the lidar system, its laser optics degraded by 50% in less than six hours of operations – not much use for a proposed three-year mission.

    “The first solution was to take extreme precautions to remove all organics,” Armandillo said. “But this did not prove entirely possible. Even at just a few parts per billion of organics, contamination was still introduced.”

    For more clues the team approached users of high-energy UV lasers in terrestrial applications. That included working closely with two German optics companies, LaserOptik and LayerTec, as well as experts at France’s Mégajoule facility – where lasers are employed to ignite nuclear fusion reactions – and the semiconductor industry. In principle, the answer proved remarkably simple. Injecting a small amount of oxygen allowed the contamination to burn up under the heat of the laser, in the process cleaning the lens. In tests, the ESA team says it saw this approach work in a matter of minutes.

    Laser breathing

    Rather than redesigning Aladin to work on a fully pressurized basis, small amounts of oxygen are released from a pair of 30-liter tanks. The oxygen gas flows close to the optical surfaces that are exposed to the UV laser, and gradually leaks out of the instrument enclosure.

    “Just like us, the laser has to breathe,” explained laser engineer Linda Mondin in a report by ESA. “It’s very elegant because the burnt-up contaminants flow out of the instrument along with this oxygen, in the form of carbon dioxide and water.” Only 25 Pascals of residual oxygen pressure is needed – just one four-thousandth of standard atmospheric pressure.

    Though contamination was the key issue facing the Aladin team, it was far from the only problem. Heat produced within the volume of the laser transmitter also needed removal. This was solved using ‘heat pipes’, which cool the laser by evaporating liquid and moving it to a space-facing radiator.

    Solving the various problems has ultimately created new technology that is set to benefit a range of future missions. Aladin’s development has yielded ESA some world-leading optics and optoelectronics capability, along with a set of ISO-certified laser development standards for other laser-based missions – starting with the “EarthCARE” mission for clouds and aerosol monitoring.

    ESA/JAXA EarthCARE satellite

    Pencilled in for launch in 2021, this will carry an atmospheric lidar instrument based around a 355 nm laser source to profile aerosols and thin clouds.

    “It’s proved an extremely complex mission, and we’ve learnt an awful lot about lasers,” concluded Rondin, with Aeolus’s instrument manager Denny Wernham adding: “The fact we have a high-power UV laser instrument now working in space is testament to all of the hard work, ingenuity, and inventiveness of many dedicated engineers in industry, ESA, and elsewhere.

    “Aeolus is a world-first mission that will hopefully lead to many active laser missions in the future, and shows the true value of close collaboration between industry and ESA to find innovative solutions to very tough technical challenges.”

    “There were so many ways it could go wrong, we were worried,” recalled Armandillo following the 2018 launch. “And then it worked! Those first wind profiles felt like Christmas coming early, a really amazing gift.”

    ICESat-2 [above]: up and running
    Just as Aeolus and its Aladin laser were starting to return those initial wind profiles from space, NASA launched its ‘ICESat-2′ satellite from California’s Vandenberg Air Force Base.

    Like Aeolus, the mission – comprising a single-instrument laser altimeter payload – was delayed and significantly over its original budget. But it has now deployed its Advanced Topographic Laser Altimeter System (ATLAS), flying in a polar orbit at an average altitude of 290 miles.

    ATLAS – Advanced Topographic Laser Altimeter System by Newton LLC

    Its job is to monitor annual changes in the height of the Greenland and Antarctic ice sheets, to a precision of just 4 mm.

    Developed by the Virginia-based photonics and engineering services company Fibertek, the two flight lasers aboard ICESat-2 emit millijoule-scale nanosecond pulses at 532 nm and a repetition rate of 10 kHz. In continuous operation over the three years of the mission, that equates to around a trillion pulses in all – with Fibertek saying that the tough performance metrics represented a significant increase in the complexity and reliability requirements for a space-based laser system.

    The optical design of ATLAS splits the laser source into three separate pairs of beams that are fired towards Earth at different angles, such that at ground level there is a 3.3 km gap between the beam pairs. This contrasts with the approach used on the original ICESat mission that flew between 2003 and 2009 but whose laser only operated at 40 Hz, and provides much denser cross-track sampling.

    For Earth scientists and studies of climate change, the altimeter should yield a height measurement every 70 cm along the orbiting track, with Fibertek saying that elevation estimates in sloped areas and rough surfaces around crevasses will be much improved.

    According to the ICESat-2 team, only about a dozen of the approximately 20 trillion photons that leave ATLAS with each laser pulse return to the satellite’s telescope after a round trip that takes around 3.3 milliseconds. To detect those scarce returning photons, the system is equipped with a 76 cm-diameter beryllium telescope. A series of filters ensures that only light of precisely 532 nm reaches the detectors, eliminating any reflected sunlight that might influence the results.

    The ATLAS laser, part of NASA’s much-delayed ICESat-2 mission, was launched in September 2018. It will provide high-precision profiles of ice sheets and sea ice for climate studies. Photo by NASA

    Just three months after launch, ICESat-2 was already exceeding scientists’ expectations. NASA said that the satellite had measured the height of sea ice to within an inch, traced the terrain of previously unmapped Antarctic valleys, surveyed remote ice sheets, and peered through forest canopies and shallow coastal waters.

    “ICESat-2 is going to be a fantastic tool for research and discovery, both for cryospheric sciences and other disciplines,” said Tom Neumann, ICESat-2 project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. Neumann and others shared the first results from the mission at the American Geophysical Union’s December 2018 meeting in Washington, DC.

    “It’s spectacular terrain,” reported Benjamin Smith, a glaciologist with the University of Washington, Seattle, and member of the ICESat-2 science team. “We’re able to measure slopes that are steeper than 45 degrees, and maybe even more, all through this [Transantarctic] mountain range.”

    The returning photons have shown high ice plateaus, crevasses in the ice 65 feet deep, and the sharp edges of ice shelves dropping into the ocean. Those first measurements will help fill in current gaps in maps of the Antarctic, Smith said, although the most critical science of the ICESat-2 mission is yet to come. As researchers refine their knowledge of exactly where the instrument is pointing, they can start to measure the rise or fall of ice sheets and glaciers.

    “Very soon, we’ll have measurements that we can compare to older measurements of surface elevation,” Smith said. “And after the satellite’s been up for a year, we’ll start to be able to watch the ice sheets change over the seasons.”

    Cold Atom Lab

    Cold Atom Lab NASA JPL

    Cold Atom Lab NASA JPL II

    Not long before the launch of the Aeolus and ICESat-2 sources, another laser system made its way to the ISS, where it is now carrying out quantum research inside the orbiting Cold Atom Lab (CAL). Part of a scientific payload that arrived in May 2018, it is based around commercial laser equipment and capable of trapping potassium and rubidium isotopes.

    By July, the space lab had produced Bose-Einstein condensates (BECs) of rubidium atoms in orbit for the first time, controlled by scientists on the ground at NASA’s Jet Propulsion Laboratory (JPL) in California. Robert Thompson, CAL project scientist and a physicist at JPL, said at the time. “It’s been a long, hard road to get here, but completely worth the struggle, because there’s so much we’re going to be able to do with this facility.”

    Although shrinking the BEC-making equipment to the size demanded for launch to the ISS has been a huge challenge, the advantages of the environment are enormous, from the point of view of quantum experimentation. Unlike on Earth, the persistent microgravity allows scientists to observe individual BECs for 5-10 seconds at a time, and to repeat measurements for up to six hours every day.

    In fact this was not quite the first cold atom experiment in space. In January 2017 the “MAIUS-1” sounding rocket launched a diode laser system for laser cooling and rubidium atom interferometry to an altitude of 243 kilometers, before returning to the ground.

    Maius-1 Payload Johannes Gutenberg Universitaet Mainz

    Developed by Humboldt University Berlin’s optical metrology research group, initial results confirmed that it was possible to carry out research on laser-cooled atoms in space, and in November 2018 the German consortium reported that it had carried out a remarkable 110 experiments on BECs during the six minutes of space travel that were possible.

    Another diode-pumped solid-state laser currently traversing the solar system sits inside an altimeter setup destined for the planet Mercury. Launched by the ESA in October, the Bepi Colombo probe is a collaboration with the Japan Aerospace Exploration Agency (JAXA).

    Designed and built by a Swiss-German-Spanish team led by engineers at the University of Bern, the altimeter kit will be used to map Mercury’s topography and surface morphology in unprecedented detail, and is said to be the first such instrument developed for a European interplanetary mission. Based around a Q-switched, nanosecond-pulsed Nd:YAG source operating at 10 Hz, it will fire relatively high-energy (50 mJ) bursts of 1064 nm light at the planet, and collect reflections from the surface around 5 ms later using a silicon avalanche photodiode, via a narrowband filter.

    Elsewhere in the solar system, NASA’s OSIRIS-REx mission has just completed its approach to the asteroid Bennu, where it is now in close orbit. Ultimately, it is set to grab a sample from the surface of the orbiting rock and bring it back to Earth, but before that Bennu had to be mapped in considerable detail to ensure that the spacecraft could be maneuvered into exactly the right orbit to achieve the close fly-by.

    That operation relied on another laser altimeter featuring a lidar scanner, to generate a detailed three-dimensional map of Bennu’s shape. Built by the Canadian Space Agency, it will help the OSIRIS-REx team identify the best location from which to grab a sample. Two lasers are on board: a high-energy source to scan the asteroid at distances between 7.5 km and 1 km from the surface, and a second low-energy emitter that can be used for rapid time-of-flight imaging down to 225 m.


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    See the full article here .

  • richardmitnick 11:48 am on April 17, 2018 Permalink | Reply
    Tags: , , , Marriage of a 20keV superconducting XFEL with a 100PW laser, , SPIE,   

    From SPIE: “Marriage of a 20keV superconducting XFEL with a 100PW laser” 



    16 April 2018
    Toshiki Tajima, University of California, Irvine
    Ruxin Li, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences

    A new regime of science at exawatts and zeptoseconds.

    The Chinese national science and technology major infrastructure, Shanghai Coherent Light Facility (SCLF), organized an international review meeting for the Station of Extreme Light (SEL) in Shanghai on July 10, 2017.

    The Shanghai Institute of Applied Physics is building a Soft X-ray Free Electron Laser that is set to open to users in 2019. Credit Michael Banks

    The reviewing committee members included experts in strong-field laser physics, high-energy-density physics, and theoretical physics from Germany, USA, UK, France, Japan, Canada; and China chaired by R. Sauerbrey and N .Wang. The working group, led by Ruxin Li of the Shanghai Institute of Optics and Fine Mechanics (SIOM), Chinese Academy of Sciences (CAS), has made a series of breakthroughs on high energy, high power, and high-repetition laser system development.

    Reflecting on this, the Review Committee Report1 stated: “The architecture of the laser system of the Optical Parametric Chirped Pulse Amplification (OPCPA) and its interaction with the XFEL are well thought out. The proposed 1023 W/cm2 peak laser power is feasible. The working group has made a series of breakthroughs on high-power laser technologies in the past decades. Their constant effort has resulted in valuable experience, outstanding engineering skills, and international recognition for the group. Their strong track record has laid a strong foundation, which will provide the basis for successful construction of the 100 PW laser system.”

    Based on this, the Committee applauded the work, stating: “The Station of Extreme Light at Shanghai Coherent Light Facility is dedicated to cutting-edge research in strong field science and applications. This includes, for example, astrophysics, nuclear physics, cosmology, and matter under extreme conditions. The combination of the hard XFEL and the world-leading 100PW laser in SEL will initiate exploration of effects such as vacuum birefringence, one of the most prominent strong-field QED effects, acceleration mechanisms leading to ultra-high energy cosmic rays, simulation of black hole physics, and generation of new forms of matter.”

    The developments proposed are based on solid research carried out at SIOM (and other scientific organizations). In particular, the research and development of the OPCPA laser amplifier at the highest power level at SIOM. Shown in Figure 1 is SIOM’s 10PW laser CPA device and the 10PW laser system. The 10PW laser system, Shanghai Superintense-Ultrafast Lasers Facility (SULF), is based on CPA technology and the diameter of the Ti-Sapphire used in the main amplifier is 235mm, which is the largest crystal for the laser manufactured by the scientists at SIOM.

    Based on these developments, SIOM has launched a 100PW laser system, Station for Extreme Light (SEL). This system has two significant salient features. First, the level of its power will be an order of magnitude beyond the planned highest-powered laser, Extreme Light Infrastructure (ELI). Secondly, its design is a combination of the 100PW laser as part of the system in the SCLF’s XFEL. This project received strong endorsement from the International Review Meeting that convened at SCLF of SIOM on July 10, 2017, and was approved by the Government of China. The overall funding level is approximately USD$1.3 Billion.

    Figure 1 10PW laser system in Shanghai pumped by CPA.

    II. Extreme field regime
    The parameters of SEL are well beyond what has so far been available. Table 1 shows typical principal physical parameters. The coherent x-ray energy from the SCLF ranges between 3 to 15 keV (hard x-rays) produced from the superconducting x-ray free electron laser (XFEL). The photon number per pulse of this XFEL is 1012. Its pulse focusability is 200nm with the energy resolution of 0.6eV. The x-ray’s intensity at focus is as high as 1021W/cm2.

    The parameters of the 100PW laser for optical photons are as follows: Its peak power is 100PW, while its focal intensity is as high as 1023W/cm2. (If we can managed to focus better than this, it could go toward 1025W/cm2). While this is a single shot performance, it could deliver the repetition rate of 1Hz of optical laser if the power is at 0.1 to 1PW.

    These parameters by themselves are exciting. However, their coexistence and marriage as a combined unit shows a remarkable capability for future scienctific exploration. The combination of a synchrotron light source and an intense laser was first suggested and conducted in 1990s. Toshiki Tajima suggested that Professor Mamoru Fujiwara at Osaka University make use of the high-energy (8GeV) electrons of the SPRing-8 combined with an intense laser to make extremely high-energy gamma photons, which he did in his lab.2 Since then, the combination of these accelerator-based synchrotron light sources (or even more advanced XFEL with intense lasers) have come a long way. The present SCLF’s marriage of these two will uncover a new regime of science and greatly impact various technologies and applications, such as nuclear photonics and nonlinear interferometry.

    Table 1 shows the schematic layout of the SEL. The interaction of XFEL and the plasma chamber takes place in the experimental area. Figure 3 indicates the 100PW laser based on the OPCPA technology.

    Figure 2: Schematic layout figure of SEL that couples the 100PW laser with the XFEL.

    Figure 3: Details of the amplification stages of the 100PW laser based on OPCPA.

    The scheme of this marriage is seen in the concept of the SEL at which the coherent high-energy x-rays photons are shone in the configuration shown in Figure 2. This way we will be able to observe the interaction of the high-energy x-ray photons and most intense lasers and their developed matter interaction. This will greatly increase the experimental probe of intense laser-matter interaction. The XFEL beam will provide ultra-short MHz x-ray beam with energy range of 3-5keV and significantly large photon number of 1012. Specific x-ray energy of 12.914keV will be used for QED experiments with very low energy spread of 0.6eV. The x-ray beam will collide head-on with the 100PW laser pulse in the experimental chamber. The 100PW laser system contains four beams and each beam reaches the peak power of 25 PW.

    Figure 2 shows that the main laser system will occupy two floors and its power supply and control system are set at different floors. After the four-beam combination, the laser pulse will be sent to the experimental area on the bottom floor. There is a large-size vacuum chamber, where the 100PW laser pulse will be focused to 5μm and collide with the x-ray beam.

    Details of the 100PW laser system are shown in Figure 3. At the core is the OPCPA system. The 100PW laser pulse starts at high temporal laser source, where its temporal synchronization signal comes from the XFEL beam. This source will generate high-quality seed pulses, which will go into the PW level repetition-rate OPCPA front-end. The laser energy will reach 25J and its spectrum width will support 15fs at PW level OPCPA front-end.

    The main amplifier is based on OPCPA technology and it provides 99% energy gain of the whole laser system, which requires sufficient pump energy from a Nd Glass pump laser. The final optics assembly will compress the high-energy of 2500J 4ns laser pulse to 15fs. After the compression, the laser pulse will be sent into the experimental chamber with the peak intensity 1023 W/cm2. As shown in Figure 1, we developed and tested the performance of a high-intensity laser with CPA up to 10PW level.

    III. High Field Science
    The proposed SEL aims to achieve the ultimate in high field science [3],[4],[5]. Here, we describe a simple way to reach that goal.

    The radiation dominance regime (1023 W/cm2) as described in Ref. 2 may be accessible and experimentally explored for the first time in sufficient details with the help of the coherent X-ray probe. As discussed in Sec. 1, if one can focus a bit narrowly, we may be able to enter the so-called QED Quantum regime (~1024 W/cm2)[4],[5].

    The particle acceleration by laser will enter a new regime. The wakefield generation [6] becomes so nonlinear that it enters what is sometimes called the bow-wake regime [7]. This may be relevant to the astrophysical extreme high-energy cosmic ray genesis by AGN (active galactic nuclei) jets [8]. In this regime, the physics of wakefield acceleration and that of the radiation pressure acceleration begin to merge (1023W/cm2)[9],[10]. Thus, the laser pulse should be able to pick up ions as well as electrons to become accelerated. Soon or later, the energy of ions begins to exceed that of electrons and their acceleration should become as coherent as the electron acceleration in this regime. Such acceleration will allow ion accelerators to be smaller. (A broader scope at this regime and slightly higher intensity regime than just mentioned has been reviewed [9].)

    However, it could go much further than that, since the invention of a new compression technique called “thin film compression11.” With this technique, a laser may be compressed to even higher power and intensity such as EW and further by relativistic compression into the shortest possible pulses ever in zs12. We will thus see the continuous manifestation of the Intensity-Pulse Duration Theorem into the extension of EW and zs [13]. It will not only explore strong field QED physics [14],[15], but we will also see the emergence of new phenomena at play in a wider variety of fundamental physics, including: (1) possible search of the proposed “fifth force” [16],[17]; (2) dark matter search by four wave mixing [18]; (3) x-ray wakefield in solid state matter [19] and related x-ray and optical solid state plasmonics [20]; (4) possible testing of the energy dependence of gamma photon propagation speed in a vacuum to test the foundational assumption of the Theory of Special Theory of Relativity [21]; and (5) zeptosecond streaking of the QED process [22].

    Chen et al.[23] suggested the exploration of general relativity using the equivalence principle of acceleration-gravity to test the Hawking-Unruh process.

    IV. Gamma-ray diagnosis and the marriage of XFEL and HFS
    In the issues of high field science, we often enter into the physical processes in higher energies and shorter timescales, which may not be easily resolvable in optical diagnosis. Here, the powerful XFEL’s resolution in time and space come in [24]. X-rays can be also signatures in high intensity experiments such as laser-driven acceleration experiments [25]. A typical display of such interplay may be seen in the diagnostics of the physical processes in the problem of x-ray wakefield acceleration in solid-state matter. In this case, nanoscopic materials with a nanohole structure [20] need to be observed and controlled. The surface of the nanotubes may be exhibiting surface plasmons and polaritons in nanometer size and zs temporal dynamics, best diagnosed by the XFEL. This is but an example of the marriage of a 20keV superconducting XFEL and a 100PW laser. In addition this technology will enhance studies in photon-induced nuclear physics [26] and the treatment of nuclear materials [27] (including nuclear waste), nuclear pharmacology, nuclear biochemistry, and medicine [28],[29].

    Another example is to use gamma photons to mediate the vacuum nonlinearity caused by intense laser pulse to exploit zeptosecond streaking via the gamma photon mediation [22]. In this scheme the presence of intense laser pulse and x-ray photon play a crucial role. If this example elucidates a beginning of exploration of zeptosecond photometric and zeptosecond optics, it would be an achievement comparable of the opening of the femtosecond optics flowing by attosecond optics [30].

    One more example of exploring the proposition was recently made for the Fifth Force [17]. In the Hungarian nuclear experiment, a mysterious photon at the energy of 17MeV was observed. The paper [5] suggested this emission of gamma photon may be due to the unknown force (the Fifth Force). It may be helpful if we can inject a large amount of monoenergetic photons at this energy to see if the reversal of this process of photon emission (i.e. injection of photon) can explore this process more quantitatively. We can check of the fifth force (17MeV gamma)16,17,31 with the process and an outcome of the following, utilizing the energy specific laser induced gamma photon interaction: e + 17MeV gamma → e + X.

    Finally, there is a recent suggestion by Day and Fairbairn [32] that XFEL laser pulses at 3.5keV may be used to investigate the astrophysically observed x-ray excess by fluorescent dark matter. Such an avenue may open up with this device. Such an effort along with the astrophysical observations may become an important interdisciplinary development.

    In order to maximize the success of these implications, we recommend the formation of a broad international collaboration with the organizations and institutions that are engaging in related fields. Learning from these labs in their technologies, practice, and collaborative engagements should reduce risks and duplications and enhance learning and the scope of experience. Collaborations with a variety technology sectors are important both for the execution of experiments and their applications.

    The authors are grateful for close discussions with all the committee members (Naiyan Wang, Roland Sauerbrey, Pisin Chen, See Leang Chin, Thomas Edward Cowan, Thomas Heinzl, Yongfeng Lu, Gerard Mourou, Edmond Turcu, Hitoki Yoneda, Lu Yu) of SEL. The discussions with Profs. T. Tait, K. Abazajian, T. Ebisuzaki, and K. Homma were also very useful. Prof. X. M. Zhang helped with our manuscript.

    1. Report of the International Review Meeting for Station of Extreme Light (2017).

    2. G. A. Mourou, T. Tajima and S. V. Bulanov, Optics in the relativistic regime, Rev. Mod. Phys. 78, p. 309, 2006.

    3. T. Tajima, K. Mima and H. Baldis, Eds., High-Field Science, Kluwer Academic/Plenum Publishers, New York, NY, 2000.

    4. T. Tajima and G. Mourou, Zettawatt-exawatt lasers and their applications in ultrastrong-field physics, Phys. Rev. ST AB 5, p. 031301, 2002.

    5. G. Mourou and T. Tajima, Summary of the IZEST science and aspiration, Eur. Phys. J. ST 223, pp. 979-984, 2014.

    6. T. Tajima and J. M. Dawson, Laser electron accelerator, Phys. Rev. Lett. 43, p. 267, 1979.

    7. C. K. Lau, P. C. Yeh, O. Luk, J. McClenaghan, T. Ebisuzaki and T. Tajima, Ponderomotive acceleration by relativistic waves, Phys. Rev. ST AB 18, p. 024401, 2015; T. Tajima, Laser acceleration in novel media, Eur. Phys. J. ST 223, pp. 1037-1044, 2014.

    8. T. Ebisuzaki and T. Tajima, Astrophysical ZeV acceleration in the relativistic jet from an accreting supermassive blackhole, Astropart. Phys. 56, pp. 9-15, 2014.

    9. T. Tajima, B. C. Barish, C. P. Barty, S. Bulanov, P. Chen, J. Feldhaus, et al., Science of extreme light infrastructure, AIP Conf. Proc. 1228, pp. 11-35, 2010.

    10. T. Esirkepov, M. Borghesi, S. V. Bulanov, G. Mourou and T. Tajima, Highly efficient relativistic-ion generation in the laser-piston regime, Phys. Rev. Lett. 92, p. 175003, 2004.

    11. G. Mourou, S. Mironov, E. Khazanov and A. Sergeev, Single cycle thin film compressor opening the door to Zeptosecond-Exawatt physics, Eur. Phys. J. ST 223, pp. 1181-1188, 2014.

    12. N. Naumova, J. Nees, I. Sokolov, and G. Mourou, Relativistic generation of isolated attosecond pulses in a λ3 focal volume, Phys. Rev. Lett. 92, p. 063902, 2004.

    13. G. Mourou and T. Tajima, More intense, shorter pulses, Science 331, pp. 41-42, 2011.

    14. M. Marklund and P. K. Shukla, Nonlinear collective effects in photon-photon and photon-plasma interactions, Rev. Mod. Phys. 78, p. 591, 2006.

    15. A. Di Piazza, C. Müller, K. Z. Hatsagortsyan and C. H. Keitel, Extremely high-intensity laser interactions with fundamental quantum systems, Rev. Mod. Phys. 84, p. 1177, 2012.

    16. A. J. Krasznahorkay, M. Csatlós, L. Csige, Z. Gácsi, J. Gulyás, M. Hunyadi, et al., Observation of anomalous internal pair creation in Be 8: a possible indication of a light, neutral boson, Phys. Rev. Lett. 116, p. 042501, 2016.

    17. J. L. Feng, B. Fornal, I. Galon, S. Gardner, J. Smolinsky, T. M. Tait and P. Tanedo, Protophobic fifth-force interpretation of the observed anomaly in Be-8 nuclear transitions, Phys. Rev. Lett. 117, p. 071803, 2016.

    18. K. Homma, D. Habs and T. Tajima, Probing the semi-macroscopic vacuum by higher-harmonic generation under focused intense laser fields, Appl. Phys. B 106, pp. 229-240, 2012.

    19. T. Tajima, Laser acceleration in novel media, Eur. Phys. J. ST 223, pp. 1037-1044, 2014.

    20. X. Zhang, T. Tajima, D. Farinella, Y. Shin, G. Mourou, J. Wheeler and B. Shen, Particle-in-cell simulation of x-ray wakefield acceleration and betatron radiation in nanotubes, Phys. Rev. AB 19, p. 101004, 2016.

    21. T. Tajima, M. Kando and M. Teshima, Feeling the texture of vacuum: laser acceleration toward PeV, Progr. Theor. Phys. 125, pp. 617-631, 2011.

    22. T. Tajima, G. Mourou and K. Nakajima, Laser acceleration, Riv. Nuovo Cim. 40, p. 1, 2017.

    23. P. Chen and G. Mourou, Accelerating plasma mirrors to investigate the black hole information loss paradox, Phys. Rev. Lett. 118, p. 045001, 2017.

    24. C. Pellegrini, A. Marinelli and S. Reiche, The physics of x-ray free-electron lasers, Rev. Mod. Phys. 88, p. 015006, 2016.

    25. S. Corde, K. T. Phuoc, G. Lambert, R. Fitour, V. Malka, A. Rousse and E. Lefebvre, Femtosecond x rays from laser-plasma accelerators, Rev. Mod. Phys. 85, p. 1, 2013.

    26. S. V. Bulanov, T. Z. Esirkepov, M. Kando, H. Kiriyama and K. Kondo, Relativistically strong electromagnetic radiation in a plasma, J. Exp. Theor. Phys. 122, pp. 426-433, 2016.

    27. S. Gales, IZEST meeting presentation, ELI-EP, French Embassy in Tokyo, 2013. https://gargantua.polytechnique.fr/siatel-web/linkto/mICYYYSI7yY6. Accessed 10 November 2017.

    28. D. Habs and U. Köster, Production of medical radioisotopes with high specific activity in photonuclear reactions with γ-beams of high intensity and large brilliance, Appl. Phys. B 103, pp. 501-519, 2011; Ö. Özdemir, Eds., Current Cancer Treatment – Novel Beyond Conventional Approaches, INTECH Open Access Publisher, 2011.

    29. A. Bracco and G. Köerner, Eds., Nuclear Physics for Medicine, Nuclear Physics European Collaboration Committee, 2014.

    30. F. Krausz and M. Ivanov, Attosecond physics, Rev. Mod. Phys. 81, p. 163, 2009.

    31. T. Tajima, T. Tait, and J. Feng, private comment, 2017.

    32. F. Day and M. Fairbairn, submitted to J. High Energy Phys., 2017.

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  • richardmitnick 3:52 pm on June 21, 2016 Permalink | Reply
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    From SPIE: “Systems engineering and science projects: lessons from MeerKAT” 



    16 June 2016
    François Kapp
    Square Kilometre Array South Africa
    Pinelands, South Africa

    Early results from the MeerKAT radio telescope project are providing guidance for scientific research enterprises, including the Square Kilometre Array telescope ‘megaproject.’

    SKA Square Kilometer Array

    Dynamic scientific research and rigorous formal engineering processes do not always make for the easiest partnerships, particularly in the development of large or ‘mega’ projects. Difficulties may arise between multiple stakeholders with conflicting interests, or there may be discrepancies between technologies and designs. Furthermore, some nine out of 10 such schemes overrun costs. [1] The MeerKAT [2] radio telescope project, however, has demonstrated that the application of systems engineering principles can be highly effective in overcoming some of these issues.

    SKA Meerkat telescope, 90 km outside the small Northern Cape town of Carnarvon
    SKA Meerkat telescope, 90 km outside the small Northern Cape town of Carnarvon,SA

    MeerKAT is currently under construction in the Karoo region of South Africa. When completed in 2017, it will consist of 64 interlinked receptors and a main reflector dish of 13.5m diameter. The project is a pathfinder to the larger Square Kilometre Array (SKA), an international collaboration to build the world’s largest radio telescope in Africa and Australia. However, MeerKAT is also a megaproject in its own right. It would therefore be prudent to capture any possible lessons from MeerKAT and to make them available to SKA. [3]

    At an early stage in MeerKAT’s development, we (the project management team) noted various technical risks for each of the project’s subsystems. For the digitizer, these risks included radio frequency interference/electromagnetic compatibility, environmental conditions (which could affect performance), and implementation (without the use of a control processor) of the 10Gb/s ethernet interfaces. For the correlator beamformer (which receives the signals from all the individual antennas and combines them), the risks were the field programmable gate arrays (FPGAs) in the programming environment, the availability of a next-generation processing platform, and the performance of the 40Gb ethernet. For the time and frequency reference subsystem, risks included the design of a synchronization solution, the effect of temperature on the distribution network, and the very long procurement cycles for hydrogen masers. To manage these perceived risks, we used a systems engineering approach. Our team created a concept design that we used to solicit science proposals from the community. We were then able to give direction to the design effort and unambiguous guidance for any trade-off decisions, such as the array layout. To meet the transient science requirements, a dense core with fewer antennas further out was preferable, while the imaging requirements called for a more distributed array with longer baselines. We built a simulation tool to evaluate different array layouts, and were able to find a good compromise.

    The correlator beamformer is an evolutionary design based on the KAT-7 [4] precursor to MeerKAT, and was thus regarded as a lower-risk element of the project because we had in-house design and implementation experience readily available. Nonetheless, the correlator beamformer was dependent on improvements in processing technology performance (notably the FPGAs), in line with Moore’s law. The other subsystems—the digitizer and the time and frequency reference system—were newly identified and without precedent in South Africa, and had requirements that were unique worldwide. The digitizer, which contains high-speed electronics, was mounted next to a very sensitive radio astronomy receiver in a dusty environment, which was prone to large temperature variation. As a result, there was a high risk of self-induced radio frequency interference, and a high probability of encountering difficulties in stabilizing sensitive analog electronics over a wide operating temperature. To compound these difficulties, the mitigation strategies we identified were limited and often resulted in increased design complexity, which would inevitably lead to challenges in achieving high availability of the system in its remote location. The time and frequency reference system required very precise timing—again in an uncontrolled environment—leading to high technical risk.

    We considered the perceived risks in each subsystem and varied our approach to their development accordingly, while also adhering to a single systems engineering management plan. For the high-risk digitizer, we undertook a classic waterfall development process in order to avoid possible changes to requirements between stages. For the correlator beamformer, we allowed the requirements to remain more flexible for a longer time. The time and frequency reference requirements also evolved over time as a result of changing scientific requirements. Instead of focusing on requirements analysis—as with the digitizer—we worked on additional modes based on the KAT-7 system. The greater risks were in the changes to requirements. For instance, we defined mode concurrency after time allocation, and this had a significant impact on the cost of the correlator beamformer hardware. As expected, the risk profiles changed during execution of the project, and prompted us to make slight variations in our approach.

    Figure 1. Digitizer units awaiting final assembly on the production line at the Square Kilometre Array radio telescope project in South Africa.

    However, it is now in full production with no remaining design risks. In contrast, the correlator beamformer (see Figure 2) still carries a number of open design risks as it approaches critical design review. The time and frequency reference system has not yet completed preliminary design review, mainly because of requirement uncertainty.

    Figure 2. The MeerKAT radio telescope project’s correlator beamformer under construction.

    Drawing on the MeerKAT experiences, we can extract several key lessons for SKA. First, we have learned that the quality of requirements (completeness, correctness, clarity, and so forth) prior to starting construction and the discipline in managing those requirements are both critical for reliable construction planning. This will be even more important for SKA, which has a distributed and culturally diverse project team (unlike the collocated and well-integrated MeerKAT team). The second lesson we have learned is that complex projects result in complex design trade-offs. To empower a design team to make rational decisions, it is essential that the engineering requirements can be traced to a small set of well-prioritized science goals.

    Our future work will prioritize the completion of MeerKAT (due in late 2017). We are currently developing new processing platforms that are potentially useful to SKA, and from 2018 we will focus on construction of that project.

    1. B. Flyvbjerg, What you should know about megaprojects and why: an overview, Proj. Manag. J. 45, p. 6-19, 2014.
    2. http://www.ska.ac.za/ Astronomers discuss the scientific potential of the MeerKAT telescope project. Accessed 6 May 2016.
    3. F. Kapp, Managing engineering in a science project: lessons for SKA from MeerKAT. Presented at SPIE Astronomical Telescopes + Instrumentation 2016.
    4. A. R. Foley, T. Alberts, R. P. Armstrong, A. Barta, E. F. Bauermeister, H. Besterand S. Blose, et al., Engineering and science highlights of the KAT-7 radio telescope, Mon. Not. R. Astron. Soc. 460, p. 1664-1679, 2016.

    See the full article here.

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  • richardmitnick 6:50 am on February 6, 2016 Permalink | Reply
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    From SPIE: “Tracking DNA damage with electrochemical sensing” 



    Jason D. Slinker
    The University of Texas at Dallas
    Richardson, TX

    DNA, the fundamental biomolecule of life, is constantly subject to damage that threatens the vitality of cells and the integrity of the genome. Without enzymatic intervention, this damage can produce mutations that lead to cancerous tumors. Furthermore, many current and developing treatments of cancer and disease rely on the generation of DNA damage products, which—from a chemical standpoint—are very subtle. For example, 8-oxoguanine, the most prevalent oxidative DNA damage product, involves the addition of a single oxygen bond to a guanine base. Remarkably, enzymes in cells recognize and remove this damage and other products of degradation. Biological assays that follow repair of this subtle DNA damage assist cancer studies by advancing fundamental understanding of DNA-protein interactions, connecting damage to diagnosis, and informing options for treatment.

    We have demonstrated devices that follow DNA damage repair in real time, with a convenient, low-cost package (see Figure 1).1 In this device, DNA is bound to the circular electrodes of multielectrode chips, and a redox probe at the top of the DNA reports charge transfer through it. DNA is the natural recognition element not only for the binding of repair proteins but also for their repair activity, and it can be synthesized with or without damage/lesion sites to establish controls. Furthermore, DNA can also serve as an electrical transducing element when modified with a redox-active probe and self-assembled on a working electrode, as first demonstrated by the Barton group.2 We have combined these features of DNA, using them to form devices capable of selectively detecting oxidative DNA damage repair (see Figure 1) and changes in DNA stability.1 The devices give a direct measure of molecular-level repair, providing a window into intracellular DNA repair by DNA-binding proteins.

    DNA Device
    Figure 1. Top: Schematic of detection of oxidative damage removal. Bottom: Image of the device used to study DNA-damaging drugs. (Photo by Randy Anderson). FPG: Formamidopyrimidine DNA glycosylase. e-: Electron.

    Specifically, we have used our approach to show sensitive and selective electrochemical sensing of 8-oxoguanine and uracil repair glycosylase activity. We produced sensors on electrospun fibers as low-cost devices with improved dynamic range. Our experiments compared electroactive, probe-modified DNA monolayers containing a base defect with the rational control of defect-free monolayers. We found damage-specific limits of detection on the order of femtomoles of proteins, corresponding to mere nanograms of the enzymes. The DNA chips enabled the real-time observation of protein activity, and we observed base excision activity on the order of seconds. We also demonstrated damage-specific detection in a mixture of enzymes and in response to environmental oxidative damage. We showed how nanofibers may behave similarly to conventional gold-on-silicon devices, revealing the potential of these low-cost devices for sensing applications. This device approach enables sensitive, selective, and rapid assay of repair protein activity, allowing biological interrogation of DNA damage repair.

    Given the ability of these devices to follow induced oxidative damage, we are further using them to follow DNA-damaging anticancer drug activity. We are working with the group of David Boothman of the University of Texas Southwestern Medical Center to sense DNA repair activity in conjunction with a novel drug therapy that selectively produces oxidative damage of DNA in cancer cells, bringing about selective cancer cell death. We represent key features of a living system to reproduce DNA damaging and repair activity pathways on the chip. Recent results have shown that we can follow specific drug-induced DNA damage excision and subsequent DNA repair with our devices. Furthermore, the multiple electrodes of the chip allowed us to perform controls of each associated enzyme and to obtain high statistical confidence of results. Given this success, we have launched studies of other DNA damaging drugs to explore the generality of this technique.

    In summary, we have designed and fabricated low-cost devices that are capable of electrochemical sensing of 8-oxoguanine and uracil repair glycosylase activity. Ultimately, in addition to their utility in bioassays of DNA-protein interactions, our devices have potential in a number of applications for public health, and our future work will focus on realizing these. The prevalence of high damage repair sites can be an indication of cancers and disease states, and these devices could provide statistically significant diagnosis. Additionally, as a number of cancer treatments involve DNA-damaging agents, our devices can be used to improve treatment outcomes. These devices could be used to sample the activity of multiple drugs with a small volume patient sample, enabling a tailored treatment based on DNA-damaging effectiveness. Similarly, they may also be used to follow the course of cancer treatment through characteristic measures of enzymatic activity of cancer cells versus healthy cells.

    See the full article here.

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