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All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Search for Daily Modulation of MeV Dark Matter Signals with DAMIC-M

Dark matter (DM) particles with sufficiently large cross sections may scatter as they travel through Earth’s bulk. The corresponding changes in the DM flux give rise to a characteristic daily modulation signal in detectors sensitive to DM-electron interactions. Here, we report results obtained from the first underground operation of the DAMIC-M prototype detector searching for such a signal from DM with MeV-scale mass. A model-independent analysis finds no modulation in the rate of 1 e − events with sidereal period, where a DM signal would appear. We then use these data to place exclusion limits on DM in the mass range [ 0.53 , 2.7 ] MeV / c 2 interacting with electrons via a dark photon mediator. Taking advantage of the time-dependent signal we improve by ∼ 2 orders of magnitude on our previous limit obtained from the total rate of 1 e − events, using the same dataset. This daily modulation search represents the current strongest limit on DM-electron scattering via ultralight mediators for DM masses around 1 MeV / c 2 . Published by the American Physical Society 2024

Arnquist, I. (ORCID:0000000256438330)↗
DOE OSTI2023

The DAMIC-M experiment: Status and first results

The DAMIC-M (DArk Matter In CCDs at Modane) experiment employs thick, fully depleted silicon charged-coupled devices (CCDs) to search for dark matter particles with a target exposure of 1 kg-year. A novel skipper readout implemented in the CCDs provides single electron resolution through multiple non-destructive measurements of the individual pixel charge, pushing the detection threshold to the eV-scale. DAMIC-M will advance by several orders of magnitude the exploration of the dark matter particle hypothesis, in particular of candidates pertaining to the so-called “hidden sector.” A prototype, the Low Background Chamber (LBC), with 20g of low background Skipper CCDs, has been recently installed at Laboratoire Souterrain de Modane and is currently taking data. We will report the status of the DAMIC-M experiment and first results obtained with LBC commissioning data.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2022

Parametric model-order-reduction development for unsteady convection

A time-averaged error indicator with POD- h Greedy is developed to drive parametric model order reduction (pMOR) for 2D unsteady natural convection in a high-aspect ratio slot parameterized with the Prandtl number, Rayleigh number, and slot angle with respect to the gravity. The error indicator is extended to accommodate the energy equation and Leray regularization. Despite being two-dimensional and laminar, the target flow regime presents several challenges: 1) there is a bifurcation in the angle parameter space; 2) the solution can be multivalued, even at steady state; and 3) the solution exhibits spatio-temporal chaos at several points in the parameter space. The authors explore several reduced-order models (ROMs) and demonstrate that Leray-regularized Galerkin ROMs provide a robust solution approach for this class of flows. They further demonstrate that error-indicated pMOR can efficiently predict several QOIs, such as mean flow, mean Nusselt number and mean turbulent kinetic energy, even in the presence of a bifurcation. Finally, they show that spatio-temporal chaos can lead to lack of reproducibility in both the full-order model and the reduced-order model and that the variance in the full-order model provides a lower bound on the pMOR error in these cases.

leray regularization↗
NASA NTRS1999

Quantum Computation by Optically Coupled Steady Atoms/Quantum-Dots Inside a Quantum Cavity

We present a model for quantum computation using $n$ steady 3-level atoms kept inside a quantum cavity, or using $n$ quantum-dots (QDs) kept inside a quantum cavity. In this model one external laser is pointed towards all the atoms/QDs, and $n$ pairs of electrodes are addressing the atoms/QDs, so that each atom is addressed by one pair. The energy levels of each atom/QD are controlled by an external Stark field given to the atom/QD by its external pair of electrodes. Transition between two energy levels of an individual atom/ QD are controlled by the voltage on its electrodes, and by the external laser. Interactions between two atoms/ QDs are performed with the additional help of the cavity mode (using on-resonance condition). Laser frequency, cavity frequency, and energy levels are far off-resonance most of the time, and they are brought to the resonance (using the Stark effect) only at the time of operations. Steps for a controlled-NOT gate between any two atoms/QDs have been described for this model. Our model demands some challenging technological efforts, such as manufacturing single-electron QDs inside a cavity. However, it promises big advantages over other existing models which are currently implemented, and might enable a much easier scale-up, to compute with many more qubits.

Pradhan, P.↗
NASA NTRS2004

Anomaly Analysis: NASA's Engineering and Safety Center Checks Recurring Shuttle Glitches

The NASA Engineering and Safety Center (NESC), set up in the wake of the Columbia accident to backstop engineers in the space shuttle program, is reviewing hundreds of recurring anomalies that the program had determined don't affect flight safety to see if in fact they might. The NESC is expanding its support to other programs across the agency, as well. The effort, which will later extend to the International Space Station (ISS), is a principal part of the attempt to overcome the normalization of deviance--a situation in which organizations proceeded as if nothing was wrong in the face of evidence that something was wrong--cited by sociologist Diane Vaughn as contributing to both space shuttle disasters.

Morring, Frank, Jr.↗
NASA NTRS2004

Full Service

NASA is moving ahead with the sole-source procurement of a Canadian robot to service the Hubble Space Telescope, gaining confidence the International Space Station (ISS) technology can perform all of the tasks shuttle-launched astronauts were scheduled to do before the Columbia accident changed everything. The U.S. agency is negotiating with MD Robotics, a MacDonald Dettwiler unit located in Brampton, Ontario, for a version of the Special Purpose Dexterous Manipulator (SPDM) the company developed for the ISS. The SPDM would be the business end of a throwaway module designed to replace batteries and gyroscopes, pull old instruments and install new ones before plunging to a targeted reentry over the Pacific.

Morring, Frank, Jr.↗
NASA NTRS2004

Lesson Learned

ASA will begin naming "a few hundred" engineers soon who will constitute the Independent. Technical Authority (ITA) recommended by the Columbia Accident Investigation Board to pro- vide an effective check and balance on space programs for safety. Within the next month, the directors of Johnson and Kennedy space centers will name "a couple of dozen at each place" to backstop human spaceflight engineers, according to Theron M. Bradley, Jr., NASA chief engineer. By the time the new fiscal year begins Oct. 1, the ITA should be fully staffed across the agency, with a system of "warrants" delineating who is an expert in what. Overseeing the whole organization

Morring, Frank, Jr.↗
NASA NTRS2004

Fallen Star

The Sept 8 mishap of the Genesis probe raised fears of the same fate happening to the Stardust comet sample return mission due to parachute into the Utah desert in 2006 with similar recovery hardware.The crash also raised a caution flag for designers of future lunar and Mars sample return missions.

Morring, Frank, Jr.↗
NASA NTRS2004

Mothers of Invention: Hubble Engineers Push Robotic 'Evolution' to Save Telescope, Enable New Exploration

Robotic technology being developed out of necessity to keep the Hubble Space Telescope operating could also lead to new levels of man-machine team-work in deep-space exploration down the road-if it survives the near-term scramble for funding. Engineers here who have devoted their NASA careers to the concept of humans servicing the telescope in orbit are planning modifications to International Space Station (ISS) robots that would leave the humans on the ground. The work. forced by post-Columbia flight rules that killed a planned shuttle-servicing mission to Hubble, marks another step in the evolution of robot-partners for human space explorers. "Hubble has always been a pathfider for this agency," says Mike Weiss. Hubble deputy program manager technical. "When the space station was flown and assembled, Hubble was the pathfinder. not just for modularity, but for operations, for assembly techniques. Exploration is the next step. Things we're going to do on Hubble are going to be applied to exploration. It's not just putting a robot in space. It's operating a robot in space. It's adapting that robot to what needs to be done the next time you're up there."

Morring, Frank, Jr.↗
NASA NTRS2004

Robot Rescue

Tests with robots and the high-fidelity Hubble Space Telescope mockup astronauts use to train for servicing missions have convinced NASA managers it may be possible to maintain and upgrade the orbiting observatory without sending a space shuttle to do the job. In a formal request last week, the agency gave bidders until July 16 to sub-mit proposals for a robotic mission to the space telescope before the end of 2007. At a minimum, the mission would attach a rocket motor to deorbit the telescope safely when its service life ends. In the best case, it would use state-of-the- art robotics to prolong its life on orbit and install new instruments. With the space shuttle off-limits for the job under strict post-Columbia safety policies set by Administrator Sean O'Keefe, NASA has designed a "straw- man" robotic mission that would use an Atlas V or Delta N to launch a 20,ooO-lb. "Hubble Robotic Vehicle" to service the telescope. There, a robotic arm would grapple it, much as the shuttle does.

Morring, Frank, Jr.↗
NASA NTRS2004

Quick Draw

A NASA spacecraft set for launch Nov. 17 is designed to help scientists determine the origin of gamma-ray bursts by pinpointing their sources in the sky and quickly focusing optical/ultraviolet and X-ray telescopes on them.

Morring, Frank, Jr.↗
NASA NTRS2004

Touchdown on Titan

Europe's Huygens probe is on target for a Dec. 25 separation from the Cassini Saturn orbiter that has carried it like a baby for more than seven years. The probe will spend three weeks coasting to a plunge into Titan's thick atmosphere on the morning of Jan. 14. If all goes as planned, the 349-kg. Huygens will spend more than 2 hr. descending by parachute to the mysterious surface of the planet-sized moon, and hopefully devote yet more time to broadcasting data after it lands. Before the day is over, Huygens is programmed to beam about 30 megabytes of data - including some 1,100 images-back to Earth through Cassini, a trip that will take some 75 min. to complete over the 1- billion-km. distance that separates the two planets. Within that data should be answers to questions that date back to 1655, when Dutch astronomer Christiaan Huygens found the moon with a homemade telescope and named it for the family of giants the ancient Greeks believed once ruled the earth. In the Solar System, there is no other world like Titan, with a nitrogen and methane atmospheric and a cold, hidden surface darker than Earth under the full Moon.

Morring, Frank, Jr.↗
NASA NTRS2004

Destinations

This is an article from Aviation Week, & Space Technology, entitled "Destinations". The strains facing the U.S. agency are discussed, such as the choice regarding a vehicle to return lunar samples, and the mission dubbed MoonRise. The U.S. space agency has enlisted the aid of academia and industry in developing new strategic plans for 13 areas, including Solar System exploration, in light of the new space initiative. As the Solar System planners work, they may be guided by some new science from the beyond.

Morring, Frank, Jr.↗
NASA NTRS2004

Risk Analysis

A National Academies panel says the Hubble Space Telescope is too valuable ;or gamblingon a long-shot robotic mission to extend its service life, and urges Directly contradicting Administrator Sean O'Keefe, who killed a planned fifth shuttle servicing mission to the telescope on grounds it was too dangerous for a human crew in the post-Challenger environment, the expert committee found that upgrades to shuttle safety actually should make it less hazardous to fly to the telescope than it was before Columbia was lost. Risks of a telescope-servicing mission are only marginally greater than the planned missions to the International Space Station (ISS) O'Keefe has authorized, the panel found. After comparing those risks to the dangers inherent in trying to develop a complex space robot in the 39 months remaining in the Hubble s estimated service life, the panel opted for the human mission to save one of the major achievements of the American space program, in the words of Louis J. Lanzerotti, its chairman.

Morring, Frank, Jr.↗
NASA NTRS2005

Following Up: Huygens Data, Questions Will Guide Cassini on Its Future Titan Passes

Planetary scientists plan to use the instruments on NASA's Cassini Saturn orbiter in future flybys of Titan to answer questions raised by Europe's Huygens probe. In particular, they hope to discover whether the dark, flat areas on the moon's surface are liquid or quasi-liquid methane seas. As the scientists plotted their next moves, European Space Agency (ESA) officials continued their investigation into how a critical command in the Huygens descent sequence was omitted costing the imaging team half of its data and rendering another Huygens instrument useless. There were suggestions that U.S. export-control rules may have hampered the sort of close international cooperation that might have caught the error.

Morring, Frank, Jr.↗
NASA NTRS2005

Backstop: Shuttle Will Fly with Outstanding Waivers; New Oversight Eases Conflicts on Safety

he space shuttle Discovery is carrying some 300 waivers to technical specifications as it enters the home stretch of its planned return to flight next month. There were about 6,000 waivers in place when Columbia crashed. Shuttle managers say they are working to reduce the number of waivers remaining by fixing the problems they highlight, a change prompted by the Columbia Accident Investigation Board. In the wake of the accident, NASA has heeded the CAWS recommendation that waivers be the responsibility of an "independent technical authority" (ITA), rather than the shuttle program itself. To carry out the recommendation of the CAIB-which found an inherent conflict of interest in having the same managers make decisions about cost, schedule and safety-then-Administrator Sean O'Keefe designated the agency's chief engineer as the formal ITA. He is responsible for setting, maintaining and granting waivers across the agency. In mid-January, Fred Gregory, then O'Keefe's deputy and now his acting replacement, launched the ITA within NASA under Chief Engineer Rex Geveden, the former program manager on the Gravity Probe B experiment.

Morring, Frank, Jr.↗
NASA NTRS2005

Griffin Lifts Off at NASA With Calls for Speeding Shuttle Replacement, Reopening Hubble Decision

Michael D. Griffin launched his tenure as NASA's 11th administrator on a fast track, using his "emergency" confiimation by the U.S. Senate to plug himself into space shuttle return-to-flight decision-making and urging faster development of the shuttle replacement. He also deftly sidestepped the treacherous issue of letting the aging Hubble Space Telescope die that was left behind by former Administrator Sean O'Keefe. Griffin told the Senate Commerce, Science and Transportation Committee that he would take another look at a shuttle mission to service the telescope, but not until the redesigned shuttle system makes a couple of test flights. Griffin made clear at his confirmation hearing Apr. 12 that he has long supported the ideas embodied in President Bush s push to move human exploration out of low Earth orbit, while finishing the International Space Station and retiring the space shuttle as soon as possible. And he showed right out of the blocks that his technical training and management background should serve him well in implementing Bush's directives.

Morring, Frank, Jr.↗
NASA NTRS2005

Game Plan

Industry proposals for the Crew Exploration Vehicle that NASA plans as a replacement for the space shuttle are due next week, but the agency's new chief says it might be necessary to slow the CEV procurement at first to speed it up later. After a quick trip to Kennedy Space Center for briefings on getting the space shuttle back in operation, Michael D. Griffin sat down with his growing staff last week to begin work on modifying the CEV procurement. "We are going to rethink our entire program in that area," he said during an inaugural press conference Apr. 18. The proposals due May 2 are being prepared in response to NASA's call for a "risk-reduction flight effort" in 2008 that would lead to delivery of a human-rated CEV in 2014. But Griffin was co-leader on an independent study in 2004 that recommended a way to get the CEV flying astronauts in 2010, the year President Bush has set as a deadline for retiring the space shuttle fleet. In that study, produced for The Planetary Society, Griffin and his team called for development of a 13-15-ton "Block 1" CEV limited to low Earth orbit (LEO) that would be launched atop a single space shuttle solid rocket motor (SRM), with a new cryogenic upper stage based on existing rocket engine technology, Under this approach, NASA would develop a "Block 2" CEV later for human exploration beyond LEO.

Morring, Frank, Jr.↗