We report results from a reanalysis of data from the Cryogenic Dark Matter Search (CDMS II) experiment at the Soudan Underground Laboratory. Data taken between October 2006 and September 2008 using ...eight germanium detectors are reanalyzed with a lowered, 2 keV recoil-energy threshold, to give increased sensitivity to interactions from weakly interacting massive particles (WIMPs) with masses below ∼10 GeV/c(2). This analysis provides stronger constraints than previous CDMS II results for WIMP masses below 9 GeV/c(2) and excludes parameter space associated with possible low-mass WIMP signals from the DAMA/LIBRA and CoGeNT experiments.
Micro-X is a sounding rocket-borne instrument that uses a microcalorimeter array to perform high-resolution X-ray spectroscopy. This instrument flew for the first time on July 22nd, 2018, from the ...White Sands Missile Range, USA. This flight marks the first successful operation of a transition-edge sensor array and its time-division multiplexing readout system in space. This launch was dedicated to the observation of the supernova remnant Cassiopeia A. A failure in the attitude control system prevented the rocket from pointing and led to no time on target. The onboard calibration source provided X-rays in flight, and it is used to compare detector performance during preflight integration, flight, and after the successful post-flight recovery. This calibration data demonstrate the capabilities of the detector in a space environment as well as its potential for future flight.
The Micro-X sounding rocket flew for the first time on July 22, 2018, becoming the first program to fly Transition-Edge Sensors and multiplexing SQUID readout electronics in space. While a rocket ...pointing failure led to no time on-target, the success of the flight systems was demonstrated. The successful flight operation of the instrument puts the program in a position to modify the payload for indirect galactic dark matter searches. The payload modifications are motivated by the science requirements of this observation. Micro-X can achieve world-leading sensitivity in the keV regime with a single flight. Dark matter sensitivity projections have been updated to include recent observations and the expected sensitivity of Micro-X to these observed fluxes. If a signal is seen (as seen in the X-ray satellites), Micro-X can differentiate an atomic line from a dark matter signature.
The Micro-X High Resolution Microcalorimeter X-Ray Imaging Rocket is a sounding rocket mission that will observe Supernova Remnants and search for keV-scale sterile neutrino dark matter. Micro-X will ...combine the excellent energy resolution of Transition Edge Sensor microcalorimeters with the imaging capabilities of a conical imaging mirror to map extended and point X-ray sources with an unprecedented combination of energy and spatial resolution. The payload has been designed to operate in the challenging conditions of a sounding rocket flight and to achieve sensitive results, in a single five-minute exposure, for each of these science goals. Micro-X's unique design considerations are presented here, along with the status of the instrument and projections for the upcoming flights. The first Micro-X flight in 2018 will observe the Puppis A supernova remnant, where it will attain nearly 13,000 counts in the 300 s exposure. The second Micro-X flight will observe the Galactic Center to search for keV-scale dark matter and explore the nature of the unexplained 3.5 keV line observed by X-ray satellites.
Micro-X is a sounding rocket-borne X-ray telescope that uses a transition edge sensor microcalorimeter array to provide high-energy-resolution spectroscopy. Micro-X is a versatile instrument with ...plans to observe the Puppis A supernova remnant during its first flight, as well as future observations of the Milky Way to search for X-ray signals from decaying dark matter. Commissioning and functionality testing are complete, and the thermal performance of the system has been validated. We are currently evaluating the detector performance in the flight cryostat with the flight multiplexing electronics. Operating in this setup has allowed us to characterize sources of detector and readout noise, as well as to implement mitigation techniques to improve performance in anticipation of the upcoming flight. We present an overview of important noise considerations in addition to an update on latest detector performance.
The common design of the cryopumps for pumping the divertor and the cryostat has been completed at ITER following more than 10 years of development including prototyping and a number of design ...studies. This final design, which will be validated by building a Pre-Production Cryopump, achieves a number of simplifications and is expected to solve issues identified in previous concepts.
The paper will present the build to print manufacturing design of the cryopump according to European Standards. The fabrication and qualification methods will be discussed and a summary of the main manufacturing methods will be given. The design of the valve assembly and its integration in the cryopump with the valve shaft double bellows will be described in detail.
Micro-X is a NASA-funded, sounding rocket-borne X-ray imaging spectrometer that will allow high precision measurements of velocity structure, ionization state and elemental composition of extended ...astrophysical systems. One of the biggest challenges in payload design is to maintain the temperature of the detectors during launch. There are several vibration damping stages to prevent energy transmission from the rocket skin to the detector stage, which causes heating during launch. Each stage should be more rigid than the outer stages to achieve vibrational isolation. We describe a major design effort to tune the resonance frequencies of these vibration isolation stages to reduce heating problems prior to the projected launch in the summer of 2014.
► Simple model of water and helium flow through ITER relevant leak geometries is proposed. ► Validation of ITER concept of leak localization based on flow water flow restrictors presented. ► Viable ...concept scheme for ITER blanket leak localization proposed.
Operational leaks into the main vacuum vessel from actively cooled in vessel components are expected to account for a significant loss of operational availability if timely localization and repair of the leak cannot be performed. Due to the complexity of the machine, and the progression to an active environment, traditional methods of leak localization may not be applicable to ITER. In order to place boundary constraints on the design of leak localization systems the conditions at the leak exit, and fluid expansion into the vacuum vessel, must be characterized. In turn, to understand the fluid conditions at the leak exit the mechanism of fluid flow through the leak must be understood. Simulations have been performed to study the flows of fluids (water and helium) through ITER relevant leak geometries. The simulations are supported by an experimental program described herein. The simulations, results and comparison with empirical data are presented in this paper. Application of the results to the design of leak localization systems is given and details of a proposed leak localization method based on the real time modification of a leak flow characteristics is presented.
Astrophysical observations indicate that dark matter constitutes most of the mass in our universe, but its nature remains unknown. Over the past decade, the Cryogenic Dark Matter Search (CDMS II) ...experiment has provided world-leading sensitivity for the direct detection of weakly interacting massive particle (WIMP) dark matter. The final exposure of our low-temperature germanium particle detectors at the Soudan Underground Laboratory yielded two candidate events, with an expected background of 0.9 ± 0.2 events. This is not statistically significant evidence for a WIMP signal. The combined CDMS II data place the strongest constraints on the WIMP-nucleon spin-independent scattering cross section for a wide range of WIMP masses and exclude new parameter space in inelastic dark matter models.
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