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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 595 records · Page 33
All sourcesNASA NTRSDOE OSTI
DOE OSTI2010

INJECTOR UPGRADE FOR THE SUPERCONDUCTING ELECTRON ACCELERATOR S-DALINAC

Since 1991 the superconducting Darmstadt linear accelerator S-DALINAC provides an electron beam of up to 130 MeV for nuclear and astrophysical experiments. The accelerator consists of an injector and four main linac cryostats, where the superconducting cavities are operated in a liquid helium bath at 2 K. Currently, the injector delivers beams of up to 10 MeV with a current of up to 60 muA. The upgrade aims to increase both parameters, the energy to 14 MeV and the current to 150 muA. Due to an increase in the required RF power to 2 kW the old coaxial RF input couplers, being designed for a maximum power of 500 W, have to be replaced by new waveguide couplers. Consequently, modifications to the cryostat-module had become necessary. We review the design principles, the necessary changes in RF components (i.e. couplers, transition line, stub tuner), the production of the SRF cavities and the new magnetic shielding. A report on the status will be given.

43 PARTICLE ACCELERATORS↗
DOE OSTI2010

THERMAL ANALYSIS OF THE FAIR SIS300 MODEL DIPOLE

Design activities, conductor R and D and model coil construction are under way for the development of a curved superconducting dipole for the fast cycled SIS300 synchrotron at FAIR at GSI. The main target is the construction within 2009 of a half-length model magnet (cold mass fully integrated in a horizontal cryostat). This magnet is designed for a maximum central field of 4.5 T in a bore of 100 mm, with a ramp rate of 1 T/s. The magnetic length of the model is 3.9 m with a curvature radius of 66.67 m (27 mm of sagitta). This paper describes the thermal analysis of the magnet, based on the estimated values of the losses in the cold mass. The study has been performed with 2-D finite element codes, both in steady state and transient analysis. The study has been completed with measurements of overall thermal exchange coefficient between the kapton-insulated cables and the supercritical helium, in order to validate the adopted assumptions about the material thermal properties.

43 PARTICLE ACCELERATORS↗
DOE OSTI2010

The ESRF Miniature Pulsed Magnetic Field System

We have developed a portable system to provide pulsed magnetic fields on the ESRF X-ray beamlines. The complete system consists of a power supply, liquid Helium and liquid Nitrogen dewars with a siphon each, control electronics and a double cryostat for separate coil and sample cooling. The liquid nitrogen cooled solenoids reach a maximum field of 30 Tesla for a total pulse duration of one milisecond. They are constructed for optimised cooling rate after the pulse to obtain a high duty cycle, the repetition rate is five pulses per minute at maximum field. The sample is cooled in an independent Helium flow cryostat which is inserted into the bore of the magnet. The flow cryostat has a temperature range from 5 to 250 Kelvin with a direct contact between the sample and Helium flow. This overview gives a general presentation of the system and we will show recent results.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2010

The materials science X-ray beamline BL8 at the DELTA storage ring

The instrumentation of the hard X-ray beamline BL8 at the 1.5 GeV Dortmund Electron Accelerator DELTA is described, and the properties of the X-ray optical elements are presented together with experimental data of different fields of research. The beamline, which makes use of the photons emitted by a superconducting asymmetric wiggler, is dedicated to X-ray studies--especially X-ray absorption spectroscopy (XAS)--in the spectral range from about 1 keV to ca. 25 keV photon energy using three different monochromators, namely YB{sub 66}(400), Si(111) and Si(311). The endstation comprises a 6-axis diffractometer that is capable of carrying heavy loads related to non-ambient sample environments such as high pressure cells, cryostats or even complete ultrahigh vacuum systems. X-ray absorption spectra from several reference compounds illustrate the performance of the beamline optics concerning e.g. energy range, energy resolution and beam stability. Fluorescence detection enables the investigation of dilute sample systems, and surface sensitive reflection mode experiments are possible for thin film studies.

36 MATERIALS SCIENCE↗
DOE OSTI2010

Continuous Flow Cryostat for X-Ray Fluorescence

A continuous Helium flow cryostat was designed and built by Cryovac GMbH to specifications given by ESRF beamline ID26. The beamline has constructed a high energy resolution X-ray emission spectrometer using multiple spherically bent analyser crystals, together with the sample and detector on a vertical Rowland circle. The double shrouded cryostat has a low profile designed to fit into the spectrometer setup, the lowest detector position allows for a Bragg angle of 85 degrees with a 1 meter diameter Rowland circle. The cryostat has a temperature range of 5 to 300 Kelvin on the sample holder which is cooled by static Helium exchange gas. The cryostat has triple windows for beam entrance, transmission and fluorescence; the latter offers an opening angle of 80 degrees horizontally and 50 degrees vertically. The cryostat can be configured to work in two different operation modes: translation or rotation. The translation mode offers a displacement of 50 mm to accommodate multiple samples on the sample holder. The rotation mode is used for polarisation studies on single crystals.We show recent results obtained on Chromium containing molecular complexes; data collection was done at a temperature of 10 Kelvin to avoid radiation damage.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2010

Sensitivity Reach of the Neutron EDM Experiment: The Electric Field Strength

The search for an electric dipole moment of the neutron tests physics beyond the Standard Model such as new sources of CP-violation and Supersymmetry. The nEDM experiment aims to improve the sensitivity on the current limit of the electric dipole moment of the neutron to <10{sup -27} e{center_dot}cm. The experiment will use a flux of Ultra Cold Neutrons (UCNs) produced and stored in a bath of superfluid He-II. A change in precession frequency is expected for a non-zero EDM when an electric field is applied parallel and antiparallel to a magnetic field across the neutron storage cell. A dominant parameter in terms of reducing the statistical uncertainty of this measurement is the strength of the applied electric field. An experiment to measure if superfluid He-II can sustain up to 50 kV/cm for a volume and electrode spacings comparable to the nEDM experiment has been constructed at Los Alamos National Laboratory. It consists in a large-area parallel plate capacitor immersed in a 200 liter central volume inside a suitable cryostat that in turn is connected to a dilution refrigerator unit. A description of test runs and the status of the experiment is presented.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Low background physics at the Kimballton Mine

The Kimballton Underground Research Facility (KURF) is home to several experiments. One consists to two HPGe detectors designed to screen candidate materials to be used in low-background experiments for radioactivity. Analysis techniques, including our efficiency calculations will be presented. We have also deployed a customized BEGe (Broad Energy Germanium) detector in a low-background cryostat. This paper will focus on the shield design, detector characteristics and measurements that can be performed with such a detector in a low-background environment.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2011

Low background aspects of GERDA

The GERDA experiment operates bare Germanium diodes enriched in {sup 76}Ge in an environment of pure liquid argon to search for neutrinoless double beta decay. A very low radioactive background is essential for the success of the experiment. We present here the research done in order to remove radio-impurities coming from the liquid argon, the stainless steel cryostat and the front-end electronics. We found that liquid argon can be purified efficiently from {sup 222}Rn. The main source of {sup 222}Rn in GERDA is the cryostat which emanates about 55 mBq. A thin copper shroud in the center of the cryostat was implemented to prevent radon from approaching the diodes. Gamma ray screening of radio-pure components for front-end electronics resulted in the development of a pre-amplifier with a total activity of less than 1 mBq {sup 228}Th.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2011

Setting up of a low temperature in-situ ion implantation and channeling facility at Kalpakkam

A simple low temperature ion implantation and ion channeling facility has been set up. Low temperatures upto 70 K has been obtained on a goniometer sample holder by connecting to a continuous flow Helium cryostat with a copper braid. Charge integration is carried out with a transmission Faraday cup with 10 mm diameter aperture and four Faraday cups for performing ion implantation and an electron suppressed 1.5 mm aperture with a TEM grid of 60% beam transmission for ion beam analysis. Typical low temperature ion implantation and channeling experiments have been carried out. Stabilization at intermediate temperatures by controlling the heater at the sample holder and improvement of the achievable lowest temperature by having liquid nitrogen cooled heat shield are in progress.

43 PARTICLE ACCELERATORS↗
DOE OSTI2011

A DUAL-BAND MILLIMETER-WAVE KINETIC INDUCTANCE CAMERA FOR THE IRAM 30 m TELESCOPE

The Neel IRAM KIDs Array (NIKA) is a fully integrated measurement system based on kinetic inductance detectors (KIDs) currently being developed for millimeter wave astronomy. The instrument includes dual-band optics allowing simultaneous imaging at 150 GHz and 220 GHz. The imaging sensors consist of two spatially separated arrays of KIDs. The first array, mounted on the 150 GHz branch, is composed of 144 lumped-element KIDs. The second array (220 GHz) consists of 256 antenna-coupled KIDs. Each of the arrays is sensitive to a single polarization; the band splitting is achieved by using a grid polarizer. The optics and sensors are mounted in a custom dilution cryostat, with an operating temperature of {approx}70 mK. Electronic readout is realized using frequency multiplexing and a transmission line geometry consisting of a coaxial cable connected in series with the sensor array and a low-noise 4 K amplifier. The dual-band NIKA was successfully tested in 2010 October at the Institute for Millimetric Radio Astronomy (IRAM) 30 m telescope at Pico Veleta, Spain, performing in-line with laboratory predictions. An optical NEP was then calculated to be around 2 x 10{sup -16} W Hz{sup -1/2} (at 1 Hz) while under a background loading of approximately 4 pW pixel{sup -1}. This improvement in comparison with a preliminary run (2009) verifies that NIKA is approaching the target sensitivity for photon-noise limited ground-based detectors. Taking advantage of the larger arrays and increased sensitivity, a number of scientifically relevant faint and extended objects were then imaged including the Galactic Center SgrB2 (FIR1), the radio galaxy Cygnus A, and the NGC1068 Seyfert galaxy. These targets were all observed simultaneously in the 150 GHz and 220 GHz atmospheric windows.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2025

Resident Tolerance to Transitional Temperature Deviation in Smart Communities

Choosing the right HVAC system or the right algorithm of implementing demand response may create significant energy and environmental gains while maintaining resident comfort. But these questions are closely related to the concept of user comfort, which in turn requires a reasonable fit between user preferences and temperature setpoints. While setting the temperature right is a well-researched question, systems in transition from one setpoint to another are currently not thoroughly addressed in research. But how tolerant the residents really are if a system spends a large share of time outside of the comfort setpoint. This study gives some early insights on how the deviation of temperature from the setpoint affect perceived resident comfort. We use two weeks of data for a smart neighborhood located in Atlanta, GA. We find that the system spends 20% - 50% of time deviating from the setpoint by more than 1℉. However, we do not find that increasing deviations cause resident complaints or increasing overrides.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2012

An Evaluation of the HVAC Load Potential for Providing Load Balancing Service

This paper investigates the potential of providing aggregated intra-hour load balancing services using heating, ventilating, and air-conditioning (HVAC) systems. A direct-load control algorithm is presented. A temperature-priority-list method is used to dispatch the HVAC loads optimally to maintain consumer-desired indoor temperatures and load diversity. Realistic intra-hour load balancing signals were used to evaluate the operational characteristics of the HVAC load under different outdoor temperature profiles and different indoor temperature settings. The number of HVAC units needed is also investigated. Modeling results suggest that the number of HVACs needed to provide a {+-}1-MW load balancing service 24 hours a day varies significantly with baseline settings, high and low temperature settings, and the outdoor temperatures. The results demonstrate that the intra-hour load balancing service provided by HVAC loads meet the performance requirements and can become a major source of revenue for load-serving entities where the smart grid infrastructure enables direct load control over the HAVC loads.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2020

Lithium and Lithium Isotopes in Earth’s Surface Cycles

Lithium and its isotopes can provide information on continental silicate weathering, which is the primary natural drawdown process of atmospheric CO 2 and a major control on climate. Lithium isotopes themselves can aid our understanding of weathering, via globally important processes such as clay formation and cation retention. Both these processes occur as part of weathering in modern surface environments, such as rivers, soil pore waters, and groundwaters, but Li isotopes can also be used to track weathering changes across major climate-change events. Lithium isotope evidence from several past climatic warming and cooling episodes shows that weathering processes respond rapidly to changes in temperature, meaning that weathering is capable of bringing climate back under control within a few tens of thousands of years.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2012

Residential Feedback Devices and Programs: Opportunities for Natural Gas

Behavior-based approaches have been a growing interest in the energy efficiency field over recent years and the use of residential energy feedback has garnered particular interest. By providing an increased level of detail, feedback can greatly increase a consumer's understanding of how energy is used in their home. This project reviewed the existing body of research on electricity feedback to identify parallel lessons for gas, discussed the benefits and challenges of different types of feedback, and identifying three feedback options that show strong potential for natural gas savings.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗