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Sample records for cryogenic linear octupole

  1. Structure and dynamics of ion clusters in linear octupole traps: Phase diagrams, chirality, and melting mechanisms

    SciTech Connect

    Yurtsever, E.; Onal, E. D.; Calvo, F.

    2011-05-15

    The stable structures and melting dynamics of clusters of identical ions bound by linear octupole radiofrequency traps are theoretically investigated by global optimization methods and molecular dynamics simulations. By varying the cluster sizes in the range of 10-1000 ions and the extent of trap anisotropy by more than one order of magnitude, we find a broad variety of stable structures based on multiple rings at small sizes evolving into tubular geometries at large sizes. The binding energy of these clusters is well represented by two contributions arising from isotropic linear and octupolar traps. The structures generally exhibit strong size effects, and chiral arrangements spontaneously emerge in many crystals. Sufficiently large clusters form nested, coaxial tubes with different thermal stabilities. As in isotropic octupolar clusters, the inner tubes melt at temperatures that are lower than the overall melting point.

  2. Linear beam raster for cryogenic targets

    SciTech Connect

    Yan, C; Sinkine, N; Wojcik, R

    2005-02-21

    Based on the H-bridge switch technique a linear beam raster system was developed in 2002. The system generates a rectangular raster pattern with highly uniform ({approx}95%) raster density distribution on cryogenic targets. The two raster frequencies are 24.96 and 25.08 kHz. The turning time at the vertex is 200 ns and the scan linearity is 98%. The beam-heating effect on the target is effectively eliminated. The new raster system allows the use of higher beam current toward 200 muA in many of the experimental proposals at end station Hall A and Hall C of the Jefferson lab.

  3. Linear cryogenic coolers for HOT infrared detectors

    NASA Astrophysics Data System (ADS)

    Veprik, A.; Riabzev, S.; Avishay, N.; Oster, D.; Tuitto, A.

    2012-06-01

    In spite of a wide spreading the uncooled night vision technologies, the cooled systems are still known to be superior in terms of working ranges, resolution and ability to recognize/track fast moving objects in dynamic infrared scenes. Recent technological advances allowed development and fielding of high temperature infrared detectors working up to 200K while showing performances typical for their 77K predecessors. The direct benefits of using such detectors are the lowering of the optical, cooling and packaging constraints resulting in smaller and cost effective optics, electronics and mechanical cryocooler. The authors are formulating requirements and general vision of prospective ultra-compact, long life, lightweight, power efficient, acoustically and dynamically quiet linear cryogenic cooler towards forthcoming infrared imagers. In particular, the authors are revealing the outcomes of the feasibility study and discuss downscaling options.

  4. A magnetically suspended linearly driven cryogenic refrigerator

    NASA Technical Reports Server (NTRS)

    Stolfi, F.; Goldowsky, M.; Ricciardelli, J.; Shapiro, P.

    1983-01-01

    This paper described a novel Stirling cycle cryogenic refrigerator which was designed, fabricated and successfully tested at Philips Laboratories. The prominent features of the machine are an electro-magnetic bearing system, a pair of moving magnet linear motors, and clearance seals with a 25 mu m radial gap. The all-metal and ceramic construction eliminates long-term organic contamination of the helium working fluid. The axial positions of the piston and displacer are electronically controlled, permitting independent adjustment of the amplitude of each and their relative phase relationship during operation. A simple passive counterbalance reduces axial vibrations. The design of the refrigerator system components is discussed and a comparison is made between performance estimates and measured results.

  5. Microminiature linear split Stirling cryogenic cooler for portable infrared imagers

    NASA Astrophysics Data System (ADS)

    Veprik, A.; Vilenchik, H.; Riabzev, S.; Pundak, N.

    2007-04-01

    Novel tactics employed in carrying out military and antiterrorist operations call for the development of a new generation of warfare, among which sophisticated portable infrared (IR) imagers for surveillance, reconnaissance, targeting and navigation play an important role. The superior performance of such imagers relies on novel optronic technologies and maintaining the infrared focal plane arrays at cryogenic temperatures using closed cycle refrigerators. Traditionally, rotary driven Stirling cryogenic engines are used for this purpose. As compared to their military off-theshelf linear rivals, they are lighter, more compact and normally consume less electrical power. Latest technological advances in industrial development of high-temperature (100K) infrared detectors initialized R&D activity towards developing microminiature cryogenic coolers, both of rotary and linear types. On this occasion, split linearly driven cryogenic coolers appear to be more suitable for the above applications. Their known advantages include flexibility in the system design, inherently longer life time, low vibration export and superior aural stealth. Moreover, recent progress in designing highly efficient "moving magnet" resonant linear drives and driving electronics enable further essential reduction of the cooler size, weight and power consumption. The authors report on the development and project status of a novel Ricor model K527 microminiature split Stirling linear cryogenic cooler designed especially for the portable infrared imagers.

  6. Experience on a cryogenic linear mechanism based on superconducting levitation

    NASA Astrophysics Data System (ADS)

    Serrano-Tellez, Javier; Romera-Juarez, Fernando; González-de-María, David; Lamensans, Mikel; Argelaguet-Vilaseca, Heribert; Pérez-Díaz, José-Luis; Sánchez-Casarrubios, Juan; Díez-Jiménez, Efrén.; Valiente-Blanco, Ignacio

    2012-09-01

    The instrumentation of many space missions requires operation in cryogenic temperatures. In all the cases, the use of mechanisms in this environment is a matter of concern, especially when long lifetime is required. With the aim of removing lifetime concerns and to benefit from the cryogenic environment, a cryogenic contactless linear mechanism has been developed. It is based on the levitation of a permanent magnet over superconductor disks. The mechanism has been designed, built, and tested to assess the performances of such technology. The levitation system solves the mechanical contact problems due to cold-welding effects, material degradation by fatigue, wearing, backlash, lubrication...etc, at cryogenic temperatures. In fact, the lower is the temperature the better the superconductor levitation systems work. The mechanism provides a wide stroke (18mm) and high resolution motion (1μm), where position is controlled by changing the magnetic field of its environment using electric-magnets. During the motion, the moving part of the mechanism levitates supported by the magnetic interaction with the high temperature type II superconductors after reaching the superconductor state down to 90K. This paper describes the results of the complete levitation system development, including extensive cryogenic testing to measure optically the motion range, resolution, run-outs and rotations in order to characterize the levitation mechanism and to verify its performance in a cryogenic environment.

  7. Octupole collectivity in nuclei

    NASA Astrophysics Data System (ADS)

    Butler, P. A.

    2016-07-01

    The experimental and theoretical evidence for octupole collectivity in nuclei is reviewed. Recent theoretical advances, covering a wide spectrum from mean-field theory to algebraic and cluster approaches, are discussed. The status of experimental data on the behaviour of energy levels and electric dipole and electric octupole transition moments is reviewed. Finally, an outlook is given on future prospects for this field.

  8. Baseline Configuration of the Cryogenic System for the International Linear Collider

    SciTech Connect

    Casas-Cubillos, J.; Claudet, S.; Parma, V.; Riddone, G.; Serio, L.; Tavian, L.; Vullierme, B.; van Weelderen, R.; Chorowski, M.; Ganni, R.; Rode, C.; Klebaner, A.; Peterson, T.; Theilacker, J.; Rousset, B.; Weisend, J.; /SLAC

    2007-06-18

    The paper discusses the main constraints and boundary conditions and describes the baseline configuration of the International Linear Collider (ILC) cryogenic system. The cryogenic layout, architecture and the cooling principle are presented. The paper addresses a plan for study and development required to demonstrate and improve the performance, to reduce cost and to attain the desired reliability.

  9. Cryogenic system for the MYRRHA superconducting linear accelerator

    SciTech Connect

    Chevalier, Nicolas R.; Junquera, Tomas; Thermeau, Jean-Pierre; Romão, Luis Medeiros; Vandeplassche, Dirk

    2014-01-29

    SCK⋅CEN, the Belgian Nuclear Research Centre, is designing MYRRHA, a flexible fast spectrum research reactor (80 MW{sub th}), conceived as an accelerator driven system (ADS), able to operate in sub-critical and critical modes. It contains a continuous-wave (CW) superconducting (SC) proton accelerator of 600 MeV, a spallation target and a multiplying core with MOX fuel, cooled by liquid lead-bismuth (Pb-Bi). From 17 MeV onward, the SC accelerator will consist of 48 β=0.36 spoke-loaded cavities (352 MHz), 34 β=0.47 elliptical cavities (704 MHz) and 60 β=0.65 elliptical cavities (704 MHz). We present an analysis of the thermal loads and of the optimal operating temperature of the cryogenic system. In particular, the low operating frequency of spoke cavities makes their operation in CW mode possible both at 4.2 K or at 2 K. Our analysis outlines the main factors that determine at what temperature the spoke cavities should be operated. We then present different cryogenic fluid distribution schemes, important characteristics (storage, transfer line, etc.) and the main challenges offered by MYRRHA in terms of cryogenics.

  10. Octupole shapes in heavy nuclei

    SciTech Connect

    Ahmad, I.

    1994-08-01

    Theoretical calculations and measurements show the presence of strong octupole correlations in thecyround states and low-lying states of odd-mass and odd-odd nuclei in the RaPa region. Evidence for octupole correlations is provided by the observation of parity doublets and reductions in M1 matrix elements, decoupling parameters, and Coriolis matrix elements Involving high-j states. Enhancement of E1 transition rates has also been observed for some of the octupole deformed nuclei. The most convincing argument for octupole deformation is provided by the similarities of the reduced alpha decay rates to the two members of parity doublets.

  11. Cryogenic Linear Ion Trap for Large-Scale Quantum Simulations

    NASA Astrophysics Data System (ADS)

    Pagano, Guido; Hess, Paul; Kaplan, Harvey; Birckelbaw, Eric; Hernanez, Micah; Lee, Aaron; Smith, Jake; Zhang, Jiehang; Monroe, Christopher

    2016-05-01

    Ions confined in RF Paul traps are a useful tool for quantum simulation of long-range spin-spin interaction models. As the system size increases, classical simulation methods become incapable of modeling the exponentially growing Hilbert space, necessitating quantum simulation for precise predictions. Current experiments are limited to less than 30 qubits due to collisions with background gas that regularly destroys the ion crystal. We present progress toward the construction of a cryogenic ion trap apparatus, which uses differential cryopumping to reduce vacuum pressure to a level where collisions do not occur. This should allow robust trapping of about 100 ions/qubits in a single chain with long lifetimes. Such a long chain will provide a platform to investigate simultaneously cooling of various vibrational modes and will enable quantum simulations that outperform their classical counterpart. Our apparatus will provide a powerful test-bed to investigate a large variety of Hamiltonians, including spin 1 and spin 1/2 systems with Ising or XY interactions. This work is supported by the ARO Atomic Physics Program, the AFOSR MURI on Quantum Measurement and Verification, the IC Fellowship Program and the NSF Physics Frontier Center at JQI.

  12. Cryogenic Linear Ion Trap for Large-Scale Quantum Simulations

    NASA Astrophysics Data System (ADS)

    Kaplan, H. B.; Hess, P. W.; Pagano, G.; Birckelbaw, E. J.; Hernandez, M.; Lee, A. C.; Smith, J.; Zhang, J.; Monroe, C.

    2016-05-01

    Ions confined in RF Paul traps are a useful tool for quantum simulation of long-range spin-spin interaction models. As the system size increases, classical simulation methods become incapable of modeling the exponentially growing Hilbert space, necessitating quantum simulation for precise predictions. Current experiments are limited to less than 30 qubits due to collisions with background gas that regularly destroys the ion crystal. We present progress toward the construction of a cryogenic ion trap apparatus, which uses differential cryopumping to reduce vacuum pressure to a level where collisions do not occur. This should allow robust trapping of about 100 ions/qubits in a single chain with long lifetimes. Such a long chain will provide a platform to investigate simultaneously cooling of various vibrational modes and will enable quantum simulations that outperform their classical counterpart. Our apparatus will provide a powerful test-bed to investigate a large variety of Hamiltonians, including spin 1 and spin 1/2 systems with Ising or XY interactions. This work is supported by the ARO Atomic Physics Program, the AFOSR MURI on Quantum Measurement and Verification, and the NSF Physics Frontier Center at JQI.

  13. Octupole correlation effects in nuclei

    SciTech Connect

    Chasman, R.R.

    1992-08-01

    Octupole correlation effects in nuclei are discussed from the point of view of many-body wavefunctions as well as mean-field methods. The light actinides, where octupole effects are largest, are considered in detail. Comparisons of theory and experiment are made for energy splittings of parity doublets; E1 transition matrix elements and one-nucleon transfer reactions.

  14. Octupole correlation effects in nuclei

    SciTech Connect

    Chasman, R.R.

    1992-01-01

    Octupole correlation effects in nuclei are discussed from the point of view of many-body wavefunctions as well as mean-field methods. The light actinides, where octupole effects are largest, are considered in detail. Comparisons of theory and experiment are made for energy splittings of parity doublets; E1 transition matrix elements and one-nucleon transfer reactions.

  15. Split Stirling linear cryogenic cooler for high-temperature infrared sensors

    NASA Astrophysics Data System (ADS)

    Veprik, A.; Zehter, S.; Vilenchik, H.; Pundak, N.

    2009-05-01

    Infrared imagers play a vital role in the modern tactics of carrying out surveillance, reconnaissance, targeting and navigation operations. The cooled systems are known to be superior to their uncooled competitors in terms of working ranges, resolution and ability to distinguish/track fast moving objects in dynamic infrared scenes. These advantages are primarily due to maintaining the infrared focal plane arrays at cryogenic temperatures using mechanical closed cycle Stirling cryogenic coolers. Recent technological advances in industrial application of high-temperature (up to 200K) infrared detectors has spurred the development of linearly driven microminiature split Stirling cryogenic coolers having inherently longer life spans, lower vibration export and better aural stealth as compared to their rotary driven rivals. Moreover, recent progress in designing highly efficient "moving magnet" resonant linear actuators and dedicated smart electronics have enabled further improvements to the cooler size, weight, power consumption, cooldown time and ownership costs. The authors report on the development and project status of a novel microminiature split Stirling linear cryogenic cooler having a shortened to 19mm cold finger and a high driving frequency (90Hz). The cooler has been specifically designed for cooling 130K infrared sensors of future portable infrared imagers, where compactness, low steady-state power consumption and fast cool-down time are of primary concern.

  16. Split Stirling linear cryogenic cooler for a new generation of high temperature infrared imagers

    NASA Astrophysics Data System (ADS)

    Veprik, A.; Zechtzer, S.; Pundak, N.

    2010-04-01

    Split linear cryocoolers find use in a variety of infrared equipment installed in airborne, heliborne, marine and vehicular platforms along with hand held and ground fixed applications. An upcoming generation of portable, high-definition night vision imagers will rely on the high-temperature infrared detectors, operating at elevated temperatures, ranging from 95K to 200K, while being able to show the performance indices comparable with these of their traditional 77K competitors. Recent technological advances in industrial development of such high-temperature detectors initialized attempts for developing compact split Stirling linear cryogenic coolers. Their known advantages, as compared to the rotary integral coolers, are superior flexibility in the system packaging, constant and relatively high driving frequency, lower wideband vibration export, unsurpassed reliability and aural stealth. Unfortunately, such off-the-shelf available linear cryogenic coolers still cannot compete with rotary integral rivals in terms of size, weight and power consumption. Ricor developed the smallest in the range, 1W@95K, linear split Stirling cryogenic cooler for demanding infrared applications, where power consumption, compactness, vibration, aural noise and ownership costs are of concern.

  17. The cryogenic performance of moving coil linear actuators

    NASA Astrophysics Data System (ADS)

    Stier, Mark T.; Stewart, Sandra H.; Leombruno, R. L.; Neuner, Jeffrey W.

    Results of an investigation of the performance of electromagnetic linear actuators at temperatures as low as 2 K are presented. The coil assembly is 1 cm long and 2 cm in diameter and consists of either NbTi superconductor wire or annealed ultrahigh purity copper wire wound on either 6061-T6 aluminum or G-10 bases. The temperature dependence of the dc force per unit current is described, and room, liquid nitrogen, and liquid helium temperature measurements of ac power dissipation and damping are presented. The present 4 K measurements show that the use of either superconducting NbTi wire or vanadium permendur steel reduces the energy efficiency of voice coils operating in an AC mode at liquid helium temperatures.

  18. Cryogen free superconducting splittable quadrupole magnet for linear accelerators

    SciTech Connect

    Kashikhin, V.S.; Andreev, N.; Kerby, J.; Orlov, Y.; Solyak, N.; Tartaglia, M.; Velev, G.; /Fermilab

    2011-09-01

    A new superconducting quadrupole magnet for linear accelerators was fabricated at Fermilab. The magnet is designed to work inside a cryomodule in the space between SCRF cavities. SCRF cavities must be installed inside a very clean room adding issues to the magnet design, and fabrication. The designed magnet has a splittable along the vertical plane configuration and could be installed outside of the clean room around the beam pipe previously connected to neighboring cavities. For more convenient assembly and replacement a 'superferric' magnet configuration with four racetrack type coils was chosen. The magnet does not have a helium vessel and is conductively cooled from the cryomodule LHe supply pipe and a helium gas return pipe. The quadrupole generates 36 T integrated magnetic field gradient, has 600 mm effective length, and the peak gradient is 54 T/m. In this paper the quadrupole magnetic, mechanical, and thermal designs are presented, along with the magnet fabrication overview and first test results.

  19. The design of a small linear-resonant, split Stirling cryogenic refrigerator compressor

    NASA Technical Reports Server (NTRS)

    Ackermann, R. A.

    1985-01-01

    The development of a small linear-resonant compressor for use in a 1/4-watt, 78K, split Stirling cryogenic refrigerator is discussed. The compressor contains the following special features: (1) a permanent-magnet linear motor; (2) resonant dynamics; (3) dynamic balancing; and (4) a close-clearance seal between the compressor piston and cylinder. This paper describes the design of the compressor, and presents component test data and system test data for the compressor driving a 1/4-watt expander.

  20. Calibration and linearity verification of capacitance type cryo level indicators using cryogenically multiplexed diode array

    NASA Astrophysics Data System (ADS)

    Karunanithi, R.; Jacob, Subhash; Singh Gour, Abhay Singh; Das, M.; Nadig, D. S.; Prasad, M. V. N.

    2012-06-01

    In space application the precision level measurement of cryogenic liquids in the storage tanks is done using triple redundant capacitance level sensor, for control and safety point of view. The linearity of each sensor element depends upon the cylindricity and concentricity of the internal and external electrodes. The complexity of calibrating all sensors together has been addressed by two step calibration methodology which has been developed and used for the calibration of six capacitance sensors. All calibrations are done using Liquid Nitrogen (LN2) as a cryogenic fluid. In the first step of calibration, one of the elements of Liquid Hydrogen (LH2) level sensor is calibrated using 700mm eleven point discrete diode array. Four wire method has been used for the diode array. Thus a linearity curve for a single element of LH2 is obtained. In second step of calibration, using the equation thus obtained for the above sensor, it is considered as a reference for calibrating remaining elements of the same LH2 sensor and other level sensor (either Liquid Oxygen (LOX) or LH2). The elimination of stray capacitance for the capacitance level probes has been attempted. The automatic data logging of capacitance values through GPIB is done using LabVIEW 8.5.

  1. Split-Stirling, linear-resonant, cryogenic refrigerators for detector cooling

    NASA Astrophysics Data System (ADS)

    Lehrfeld, D.

    1983-12-01

    For the past decade, military IR systems have preferred to see cryogenic coolers provided as split units; separating the functions of compressor and cold-end for system packaging and vibration isolation reasons. A family of split-cycle coolers designed for long MTBF and in the final stages of development is the focus of the discussion. Their technological evolution, from multi-year-MTBF satellite system Stirling coolers developed in the U.S., and the UA 7011 cooler (the first all-linear, military, production cooler) developed in Holland, is explained. Two new split-cycle machines are discussed. They provided 1/4 watt and 1 watt (nominal capacity) at 80 K and 85 K respectively. These linear-resonant, free-displacer Stirling coolers are designed for thousands of hours of service-free operation. They are designed to be compatible with standard U.S. 60 element and 120/180 element detector/dewars, respectively.

  2. Split-Stirling, linear-resonant, cryogenic refrigerators for detector cooling

    NASA Technical Reports Server (NTRS)

    Lehrfeld, D.

    1983-01-01

    For the past decade, military IR systems have preferred to see cryogenic coolers provided as split units; separating the functions of compressor and cold-end for system packaging and vibration isolation reasons. A family of split-cycle coolers designed for long MTBF and in the final stages of development is the focus of the discussion. Their technological evolution, from multi-year-MTBF satellite system Stirling coolers developed in the U.S., and the UA 7011 cooler (the first all-linear, military, production cooler) developed in Holland, is explained. Two new split-cycle machines are discussed. They provided 1/4 watt and 1 watt (nominal capacity) at 80 K and 85 K respectively. These linear-resonant, free-displacer Stirling coolers are designed for thousands of hours of service-free operation. They are designed to be compatible with standard U.S. 60 element and 120/180 element detector/dewars, respectively.

  3. Novel concept for driving the linear compressor of a micro-miniature split Stirling cryogenic cooler

    NASA Astrophysics Data System (ADS)

    Maron, V.; Veprik, A.; Finkelstein, L.; Vilenchik, H.; Ziv, I.; Pundak, N.

    2009-05-01

    New methods of carrying out homeland security and antiterrorist operations call for the development of a new generation of mechanically cooled, portable, battery powered infrared imagers, relying on micro-miniature Stirling cryogenic coolers of rotary or linear types. Since split Stirling linearly driven micro-miniature cryogenic coolers have inherently longer life spans, low vibration export and better aural stealth as compared to their rotary driven rivals, they are more suitable for the above applications. The performance of such cryogenic coolers depends strongly on the efficacy of their electronic drivers. In a traditional approach, the PWM power electronics produce the fixed frequency tonal driving voltage/current, the magnitude of which is modulated via a PID control law so as to maintain the desired focal plane array temperature. The disadvantage of such drivers is that they draw high ripple current from the system's power bus. This results in the need for an oversized DC power supply (battery packs) and power electronic components, low efficiency due to excessive conductive losses and high residual electromagnetic interference which in turn degrades the performance of other systems connected to the same power bus. Without either an active line filter or large and heavy passive filtering, other electronics can not be powered from the same power bus, unless they incorporate heavy filtering at their inputs. The authors present the results of a feasibility study towards developing a novel "pumping" driver consuming essentially constant instant battery power/current without making use of an active or passive filter. In the tested setup, the driver relies on a bidirectional controllable bridge, invertible with the driving frequency, and a fast regulated DC/DC converter which maintains a constant level of current consumed from the DC power supply and thus operates in input current control mode. From the experimental results, the steady-state power consumed by the

  4. Note: New design of a cryogenic linear radio frequency multipole trap

    SciTech Connect

    Asvany, Oskar; Bielau, Frank; Moratschke, Damian; Krause, Juergen; Schlemmer, Stephan

    2010-07-15

    A new design of a cryogenic linear 22-pole ion trap has been constructed and tested. It is essentially a copper housing to which opposite inner walls two electrode sets are attached via sapphire insulators. These stainless steel electrodes are electroformed in one piece to guarantee good heat conduction. Connected to an external coil, they form an LC-circuit of about 19 MHz resonance frequency. This circuit is excited with a rf power supply made of a commercial digital synthesizer followed by a 10 W amplifier. Buffer gas-cooled H{sub 2}D{sup +} ions have been stored in this trap at a nominal trap temperature of 14 K. Spectroscopy of the ions confirmed that the kinetic (Doppler) temperature is in reasonable agreement with this value.

  5. Note: New design of a cryogenic linear radio frequency multipole trap.

    PubMed

    Asvany, Oskar; Bielau, Frank; Moratschke, Damian; Krause, Jürgen; Schlemmer, Stephan

    2010-07-01

    A new design of a cryogenic linear 22-pole ion trap has been constructed and tested. It is essentially a copper housing to which opposite inner walls two electrode sets are attached via sapphire insulators. These stainless steel electrodes are electroformed in one piece to guarantee good heat conduction. Connected to an external coil, they form an LC-circuit of about 19 MHz resonance frequency. This circuit is excited with a rf power supply made of a commercial digital synthesizer followed by a 10 W amplifier. Buffer gas-cooled H(2)D(+) ions have been stored in this trap at a nominal trap temperature of 14 K. Spectroscopy of the ions confirmed that the kinetic (Doppler) temperature is in reasonable agreement with this value. PMID:20687768

  6. Octupole correlations in the heavy elements

    SciTech Connect

    Chasman, R.R.

    1986-01-01

    The effects of octupole correlations on the nuclear structure of the heavy elements are discussed. The cluster model description of the heavy elements is analyzed. The relevance of 2/sup 6/-pole deformation and fast El transitions to an octupole model is considered. 30 refs., 21 figs., 1 tab.

  7. Photoelectron-photofragment coincidence spectroscopy in a cryogenically cooled linear electrostatic ion beam trap

    SciTech Connect

    Johnson, Christopher J.; Shen, Ben B.; Poad, Berwyck L. J.; Continetti, Robert E.

    2011-10-15

    A cryogenically cooled linear electrostatic ion beam trap for use in photoelectron-photofragment coincidence (PPC) spectroscopy is described. Using this instrument, anions created in cold, low-duty-cycle sources can be stored for many seconds in a {approx}20 K environment to cool radiatively, removing energetic uncertainties due to vibrationally excited precursor anions. This apparatus maintains a well-collimated beam necessary for high-resolution fragment imaging and the high experimental duty cycle needed for coincidence experiments. Ion oscillation is bunched and phase-locked to a modelocked laser, ensuring temporal overlap between ion bunches and laser pulses and that ions are intersected by the laser only when travelling in one direction. An electron detector is housed in the field-free center of the trap, allowing PPC experiments to be carried out on ions while they are stored and permitting efficient detection of 3-dimensional electron and neutral recoil trajectories. The effects of trapping parameters on the center-of-mass trajectories in the laser-ion interaction region are explored to optimize neutral particle resolution, and the impact of bunching on ion oscillation is established. Finally, an initial demonstration of radiative cooling is presented.

  8. Development and performance validation of a cryogenic linear stage for SPICA-SAFARI verification

    NASA Astrophysics Data System (ADS)

    Ferrari, Lorenza; Smit, H. P.; Eggens, M.; Keizer, G.; de Jonge, A. W.; Detrain, A.; de Jonge, C.; Laauwen, W. M.; Dieleman, P.

    2014-07-01

    In the context of the SAFARI instrument (SpicA FAR-infrared Instrument) SRON is developing a test environment to verify the SAFARI performance. The characterization of the detector focal plane will be performed with a backilluminated pinhole over a reimaged SAFARI focal plane by an XYZ scanning mechanism that consists of three linear stages stacked together. In order to reduce background radiation that can couple into the high sensitivity cryogenic detectors (goal NEP of 2•10-19 W/√Hz and saturation power of few femtoWatts) the scanner is mounted inside the cryostat in the 4K environment. The required readout accuracy is 3 μm and reproducibility of 1 μm along the total travel of 32 mm. The stage will be operated in "on the fly" mode to prevent vibrations of the scanner mechanism and will move with a constant speed varying from 60 μm/s to 400 μm/s. In order to meet the requirements of large stroke, low dissipation (low friction) and high accuracy a DC motor plus spindle stage solution has been chosen. In this paper we will present the stage design and stage characterization, describing also the measurements setup. The room temperature performance has been measured with a 3D measuring machine cross calibrated with a laser interferometer and a 2-axis tilt sensor. The low temperature verification has been performed in a wet 4K cryostat using a laser interferometer for measuring the linear displacements and a theodolite for measuring the angular displacements. The angular displacements can be calibrated with a precision of 4 arcsec and the position could be determined with high accuracy. The presence of friction caused higher values of torque than predicted and consequently higher dissipation. The thermal model of the stage has also been verified at 4K.

  9. Modified octupoles for damping coherent instabilities

    SciTech Connect

    Cornacchia, M. . Stanford Synchrotron Radiation Lab.); Corbett, W.J. ); Halbach, K. )

    1991-05-01

    The introduction tune spread in circular e{sup +}e{sup {minus}} accelerators with modified octupoles to reduce the loss of dynamic aperture is discussed. The new magnet design features an octupole of field component on-axis and a tapered field structure off-axis to minimize loss of dynamic aperture. Tracking studies show that the modified octupoles can produce the desired tune spread in SPEAR without compromising confinement of the beam. The technique for designing such magnets is presented, together with an example of magnets that give the required field distribution. 7 refs., 7 figs.

  10. Octupole collectivity in 94Zr

    NASA Astrophysics Data System (ADS)

    Toh, Y.; Oshima, M.; Koizumi, M.; Osa, A.; Kimura, A.; Sugawara, M.; Goto, J.

    2009-01-01

    The Zr isotopes between 90Zr and 96Zr are expected to be spherical based on the almost complete subshell closures at Z = 40 and N = 50, 56. On the other hand, they have low-lying 3- states and show the characteristics of low frequency octupole oscillation which arise as a superposition of particle-hole excitations. A 380 MeV 94Zr beam from the tandem accelerator at the Japan Atomic Energy Agency (JAEA) was excited on a self-supporting natPb target. The gamma-ray detector array GEMINI-II was used to detect deexcitation gamma rays. The scattered beam (94Zr) was detected with a position-sensitive particle detector system. The gamma-ray intensities were used as an input to the least-squares search code GOSIA to determine the E3 matrix element of the first 3- excited state of 94Zr. The B(E3;0+→3-) value of 0.21(6) e2b3 in 94Zr has been obtained by Coulomb excitation experiment.

  11. Refrigeration for Cryogenic Sensors

    NASA Technical Reports Server (NTRS)

    Gasser, M. G. (Editor)

    1983-01-01

    Research in cryogenically cooled refrigerators is discussed. Low-power Stirling cryocoolers; spacecraft-borne long-life units; heat exchangers; performance tests; split-stirling, linear-resonant, cryogenic refrigerators; and computer models are among the topics discussed.

  12. Nonaxial-octupole effect in superheavy nuclei

    SciTech Connect

    Chen, Y.-S.; Sun, Yang; Gao Zaochun

    2008-06-15

    The triaxial-octupole Y{sub 32} correlation in atomic nuclei has long been expected to exist but experimental evidence has not been clear. We find, in order to explain the very low-lying 2{sup -} bands in the transfermium mass region, that this exotic effect may manifest itself in superheavy elements. Favorable conditions for producing triaxial-octupole correlations are shown to be present in the deformed single-particle spectrum, which is further supported by quantitative Reflection Asymmetric Shell Model calculations. It is predicted that the strong nonaxial-octupole effect may persist up to the element 108. Our result thus represents the first concrete example of spontaneous breaking of both axial and reflection symmetries in the heaviest nuclear systems.

  13. Evolution of octupole correlations in 123Ba

    NASA Astrophysics Data System (ADS)

    Chen, X. C.; Zhao, J.; Xu, C.; Hua, H.; Shneidman, T. M.; Zhou, S. G.; Wu, X. G.; Li, X. Q.; Zhang, S. Q.; Li, Z. H.; Liang, W. Y.; Meng, J.; Xu, F. R.; Qi, B.; Ye, Y. L.; Jiang, D. X.; Cheng, Y. Y.; He, C.; Sun, J. J.; Han, R.; Niu, C. Y.; Li, C. G.; Li, P. J.; Wang, C. G.; Wu, H. Y.; Li, Z. H.; Zhou, H.; Hu, S. P.; Zhang, H. Q.; Li, G. S.; He, C. Y.; Zheng, Y.; Li, C. B.; Li, H. W.; Wu, Y. H.; Luo, P. W.; Zhong, J.

    2016-08-01

    High-spin states of 123Ba have been studied via the 108Cd(19F,3 n p )123Ba fusion-evaporation reaction at a beam energy of 90 MeV. Several E 1 transitions linking the positive-parity ν (d5 /2+g7 /2) band and negative-parity ν h11 /2 band are observed in 123Ba for the first time. Evidence for the existence of octupole correlations in 123Ba is presented based on the systematic comparisons of the B (E 1 )/B (E 2 ) branching ratios and the energy displacements in odd-A Ba isotopes. The characteristics of octupole correlation in the odd-A Ba,125123 are explained by the state-of-the-art multidimensionally-constrained relativistic mean-field model and cluster model based on the dinuclear system concept.

  14. High Precision Piezoelectric Linear Motors for Operations at Cryogenic Temperatures and Vacuum

    NASA Technical Reports Server (NTRS)

    Wong, D.; Carman, G.; Stam, M.; Bar-Cohen, Y.; Sen, A.; Henry, P.; Bearman, G.; Moacanin, J.

    1995-01-01

    The use of an electromechanical device for optically positioning a mirror system during the pre-project phase of the Pluto Fast Flyby mission was evaluated at JPL. The device under consideration was a piezoelectric driven linear motor functionally dependent upon a time varying electric field which induces displacements ranging from submicrons to millimeters with positioning accuracy within nanometers.

  15. High Precision Piezoelectric Linear Motors for Operations at Cryogenic Temperatures and Vacuum

    NASA Technical Reports Server (NTRS)

    Wong, D.; Carman, G.; Stam, M.; Bar-Cohen, Y.; Sen, A.; Henry, P.; Bearman, G.; Moacanin, J.

    1995-01-01

    The Jet Propulsion Laboratory evaluated the use of an electromechanical device for optically positioning a mirror system during the pre-project phase of the Pluto-Fast-Flyby (PFF) mission. The device under consideration was a piezoelectric driven linear motor functionally dependent upon a time varying electric field which induces displacements ranging from submicrons to millimeters with positioning accuracy within nanometers. Using a control package, the mirror system provides image motion compensation and mosaicking capabilities. While this device offers unique advantages, there were concerns pertaining to its operational capabilities for the PFF mission. The issues include irradiation effects and thermal concerns. A literature study indicated that irradiation effects will not significantly impact the linear motor's operational characteristics. On the other hand, thermal concerns necessitated an in depth study.

  16. Linear and nonlinear optomechanics in a cryogenic membrane-in-the-middle system

    NASA Astrophysics Data System (ADS)

    Lee, Donghun; Underwood, Mitchell; Mason, David; Shkarin, Alexey; Hoch, Scott; Harris, Jack

    2014-03-01

    In cavity optomechanics, linear optomechanical interactions have been used to readout and cool the motion of mechanical oscillators, while nonlinear interactions have been proposed to study quantum non-demolition measurements of mechanical oscillators and the production of non-Gaussian mechanical states. A membrane-in-the-middle system can provide both types of interactions. In this talk, we will present recent results measured in both linear and nonlinear interaction regimes with a membrane-in-the-middle system operating at 500 mK. Linear coupling in this device enables us to cool the mechanical mode of a SiN membrane at 705 kHz to roughly one phonon. During the cooling measurement, we also observed strong asymmetry between the mechanical sidebands, in agreement with the phonon number inferred from other measurements. We also measured nonlinear optomechanics, in particular the quadratic interaction. With a simple theoretical model, we systematically characterized the classical dynamics arising from this quadratic optomechanical interaction. We expect that by combining quadratic coupling with resolved-sideband laser cooling, this device will be able to explore the aforementioned quantum phenomena. We gracefully acknowledge financial support from AFOSR (No. FA9550-90-1-0484).

  17. Octupole and hexadecapole bands in 152Sm

    SciTech Connect

    Garrett, P E; Kulp, W D; Wood, J L; Bandyopadhyay, D; Christen, S; Choudry, S; Dewald, A; Fitzler, A; Fransen, C; Jessen, K; Jolie, J; Kloezer, A; Kudejova, P; Kumar, A; Lesher, S R; Linnemann, A; Lisetskiy, A; Martin, D; Masur, M; McEllistrem, M T; Moller, O; Mynk, M; Orce, J N; Pejovic, P; Pissulla, T; Regis, J; Schiller, A; Tonev, D; Yates, S W

    2005-05-13

    The nucleus {sup 152}Sm is characterized by a variety of low-energy collective modes, conventionally described as rotations, {beta} vibrations, and {gamma} vibrations. Recently, it has been suggested that {sup 152}Sm is at a critical point between spherical and deformed collective phases. Consequently, {sup 152}Sm is being studied by a variety of techniques, including radioactive decay, multi-step Coulomb excitation, in-beam ({alpha},2n{gamma}) {gamma}-ray spectroscopy, and (n,n'{gamma}) spectroscopy. The present work focuses on the latter two reactions; these have been used to investigate the low-lying bands associated with the octupole degree of freedom, including one built on the first excited 0{sup +} band. In addition, the K{sup {pi}} = 4{sup +} hexadecapole vibrational band has been identified.

  18. Evidence for Octupole Correlations in Multiple Chiral Doublet Bands

    NASA Astrophysics Data System (ADS)

    Liu, C.; Wang, S. Y.; Bark, R. A.; Zhang, S. Q.; Meng, J.; Qi, B.; Jones, P.; Wyngaardt, S. M.; Zhao, J.; Xu, C.; Zhou, S.-G.; Wang, S.; Sun, D. P.; Liu, L.; Li, Z. Q.; Zhang, N. B.; Jia, H.; Li, X. Q.; Hua, H.; Chen, Q. B.; Xiao, Z. G.; Li, H. J.; Zhu, L. H.; Bucher, T. D.; Dinoko, T.; Easton, J.; Juhász, K.; Kamblawe, A.; Khaleel, E.; Khumalo, N.; Lawrie, E. A.; Lawrie, J. J.; Majola, S. N. T.; Mullins, S. M.; Murray, S.; Ndayishimye, J.; Negi, D.; Noncolela, S. P.; Ntshangase, S. S.; Nyakó, B. M.; Orce, J. N.; Papka, P.; Sharpey-Schafer, J. F.; Shirinda, O.; Sithole, P.; Stankiewicz, M. A.; Wiedeking, M.

    2016-03-01

    Two pairs of positive-and negative-parity doublet bands together with eight strong electric dipole transitions linking their yrast positive- and negative-parity bands have been identified in 78Br. They are interpreted as multiple chiral doublet bands with octupole correlations, which is supported by the microscopic multidimensionally-constrained covariant density functional theory and triaxial particle rotor model calculations. This observation reports the first example of chiral geometry in octupole soft nuclei.

  19. Chaos in axially symmetric potentials with octupole deformation

    SciTech Connect

    Heiss, W.D.; Nazmitdinov, R.G.; Radu, S. Departamento de Fisica Teorica C-XI, Universidad Autonoma de Madrid, E-28049, Madrid )

    1994-04-11

    Classical and quantum mechanical results are reported for the single particle motion in a harmonic oscillator potential which is characterized by a quadrupole deformation and an additional octupole deformation. The chaotic character of the motion is strongly dependent on the quadrupole deformation in that for a prolate deformation virtually no chaos is discernible while for the oblate case the motion shows strong chaos when the octupole term is turned on.

  20. Evidence for Octupole Correlations in Multiple Chiral Doublet Bands.

    PubMed

    Liu, C; Wang, S Y; Bark, R A; Zhang, S Q; Meng, J; Qi, B; Jones, P; Wyngaardt, S M; Zhao, J; Xu, C; Zhou, S-G; Wang, S; Sun, D P; Liu, L; Li, Z Q; Zhang, N B; Jia, H; Li, X Q; Hua, H; Chen, Q B; Xiao, Z G; Li, H J; Zhu, L H; Bucher, T D; Dinoko, T; Easton, J; Juhász, K; Kamblawe, A; Khaleel, E; Khumalo, N; Lawrie, E A; Lawrie, J J; Majola, S N T; Mullins, S M; Murray, S; Ndayishimye, J; Negi, D; Noncolela, S P; Ntshangase, S S; Nyakó, B M; Orce, J N; Papka, P; Sharpey-Schafer, J F; Shirinda, O; Sithole, P; Stankiewicz, M A; Wiedeking, M

    2016-03-18

    Two pairs of positive-and negative-parity doublet bands together with eight strong electric dipole transitions linking their yrast positive- and negative-parity bands have been identified in ^{78}Br. They are interpreted as multiple chiral doublet bands with octupole correlations, which is supported by the microscopic multidimensionally-constrained covariant density functional theory and triaxial particle rotor model calculations. This observation reports the first example of chiral geometry in octupole soft nuclei. PMID:27035296

  1. Octupole shaps in nuclei, and some rotational consequences thereof

    SciTech Connect

    Nazarewicz, W.; Olanders, P.; Ragnarsson, I.; Dudek, J.; Leander, G.A.

    1984-01-01

    During the last years a large number of experimental papers presenting spectroscopic evidence for collective dipole and octupole deformations have appeared. Many theoretical attempts have been made to explain the observed spectroscopic properties in terms of stable octupole deformations. The coupling by the octupole potential, being proportional to Y/sub 30/, is strongest for those subshells for which ..delta..1 = 3. Therefore the tendency towards octupole deformation occurs just beyond closed shells where the high-j intruder subshells (N,1,j) lie very close to the normal parity subshells (N-1,1-3,j-3), i.e. for the particle numbers 34 (g/sub 9/2/-p/sub 3/2/), 56 (h/sub 11/2/-d/sub 5/2/). 9C (i/sub 13/2/-f/sub 7/2/) and 134 (j/sub 15/2/-g/sub 9/2/). Empirically, it is specifically for the particle numbers listed above that negative parity states are observed at relatively low energies in doubly even nuclei. From the different combinations of octupole-driving particle numbers four regions of likely candidates for octupole deformed equilibrium shapes emerge, namely the neutron-deficient nuclei with Z approx. = 90, N approx. = 134 (light actinides) and Z approx. = 34, N approx. = 34 (A approx. = 70) and the neutron-rich nuclei with Z approx. = 56, N approx. = 90 (heavy Ba) and Z approx. = 34, N/sup 56/ (A approx. = 90). In our calculations we searched for octupole unstable nuclei in these four mass regions. The Strutinsky method with the deformed Woods-Saxon potential was employed. The macroscopic part consists of a finite-range liquid drop energy, where both the surface and Coulomb terms contain a diffuseness correction.

  2. Search for octupole correlations in 147Nd

    NASA Astrophysics Data System (ADS)

    Ruchowska, E.; Mach, H.; Kowal, M.; Skalski, J.; Płóciennik, W. A.; Fogelberg, B.

    2015-09-01

    Properties of excited states in 147Nd have been studied with the multispectra and γ γ coincidence measurements. Twenty-four new γ lines and three new levels have been introduced into the level scheme of 147Nd. Using the advanced time-delayed β γ γ (t ) method, we measured lifetimes of eight excited levels in 147Nd, populated via the β decay of 147Pr. We have determined reduced transition probabilities for 30 γ transitions. Multidimensional potential energy surface calculations performed for 147Nd suggest two single-quasiparticle configurations with nonzero octupole deformation, with K =1 /2 and K =5 /2 . Our calculations also predict a sizable value of the electric dipole moment | D0|=0.26 e fm for this nucleus, while experimentally, a lower limit of | D0|≥0.02 e fm has been evaluated for the supposed K =1 /2 parity doublet. In contrast to the theoretical results, we do not observe the parity doublet bands with K =5 /2 . This, and the lack of theoretically expected E 1 strength in Nd,149147 may signal some poorly understood structural effect in the odd-N lanthanides.

  3. Crystallization of ion clouds in octupole traps: Structural transitions, core melting, and scaling laws

    SciTech Connect

    Calvo, F.; Champenois, C.; Yurtsever, E.

    2009-12-15

    The stable structures and melting properties of ion clouds in isotropic octupole traps are investigated using a combination of semianalytical and numerical models, with a particular emphasis at finite-size scaling effects. Small-size clouds are found to be hollow and arranged in shells corresponding approximately to the solutions of the Thomson problem. The shell structure is lost in clusters containing more than a few thousands of ions, the inner parts of the cloud becoming soft and amorphous. While melting is triggered in the core shells, the melting temperature follows the rule expected for three-dimensional dense particles, with a depression scaling linearly with the inverse radius.

  4. Periodic orbits and shell structure in octupole deformed potentials

    SciTech Connect

    Heiss, W.D. ); Nazmitdinov, R.G. ); Radu, S. )

    1995-01-15

    The effect of an octupole term in a quadrupole deformed single-particle potential is studied from the classical and quantum-mechanical viewpoint. Whereas the problem is nonintegrable, the quantum-mechanical spectrum nevertheless shows some shell structure in the superdeformed prolate case for particular, yet fairly large octupole strengths; for spherical or oblate deformation the shell structure disappears. This result is associated with classical periodic orbits that are found by employing the removal of resonances method; this approximation method allows determination of the shape of the orbit and of the approximate octupole coupling strength for which it occurs. The validity of the method is confirmed by solving numerically the classical equations of motion. The quantum-mechanical shell structure is analyzed using the particle-number dependence of the fluctuating part of the total energy. In accordance with the classical result, this dependence turns out to be very similar for a superdeformed prolate potential plus octupole term and a hyperdeformed prolate potential without octupole term. In this way the shell structure is explained at least for some few hundred levels. The Fourier transform of the level density further corroborates these findings.

  5. Two-phonon octupole excitation in {sup 146}Gd

    SciTech Connect

    Caballero, L.; Rubio, B.; Nacher, E.; Kleinheinz, P.; Yates, S. W.; Algora, A.; Dewald, A.; Fitzler, A.; Jolie, J.; Linnemann, A.; Moeller, O.; Gadea, A.; Julin, R.; Piiparinen, M.; Lunardi, S.; Menegazzo, R.; Blomqvist, J.

    2010-03-15

    Based on experimental evidence from the {sup 144}Sm({alpha},2n) reaction, the 3484.7-keV 6{sup +} state in {sup 146}Gd is identified as the highest-spin member of the 3{sup -} x 3{sup -} two-phonon octupole quartet. A previously unknown {gamma} line of 1905.8 keV and E3 character feeding the 3{sup -} octupole state has been observed. These results represent the first observation of a 6{sup +}->3{sup -}->0{sup +} cascade of two E3 transitions in an even-even nucleus and provide strong support for the interpretation of the 6{sup +} state as a two-phonon octupole excitation.

  6. A superconducting linear motor drive for a positive displacement bellows pump for use in the g-2 cryogenics system

    SciTech Connect

    Green, M.A.

    1994-10-01

    Forced two-phase cooling of indirectly cooled magnets requires circulation of liquid helium through the magnet cooling channel. A bellows helium pump is one possible way of providing helium flow to a magnet cooling system. Since the bellows type of helium pump is immersed in liquid helium, a superconducting linear motor drive appears to be an attractive option. This report describes a linear motor drive that employs oriented permanent magnet materials such as samarium-cobalt as the stator magnet system and a superconducting loud speaker voice coil type of drive as the armature of the linear motor. This report examines drive motor requirements for a helium pump.

  7. Octupole strength in the neutron-rich calcium isotopes

    NASA Astrophysics Data System (ADS)

    Riley, L. A.; McPherson, D. M.; Agiorgousis, M. L.; Baugher, T. R.; Bazin, D.; Bowry, M.; Cottle, P. D.; DeVone, F. G.; Gade, A.; Glowacki, M. T.; Gregory, S. D.; Haldeman, E. B.; Kemper, K. W.; Lunderberg, E.; Noji, S.; Recchia, F.; Sadler, B. V.; Scott, M.; Weisshaar, D.; Zegers, R. G. T.

    2016-04-01

    Low-lying excited states of the neutron-rich calcium isotopes Ca-5248 have been studied via γ -ray spectroscopy following inverse-kinematics proton scattering on a liquid hydrogen target using the GRETINA γ -ray tracking array. The energies and strengths of the octupole states in these isotopes are remarkably constant, indicating that these states are dominated by proton excitations.

  8. Cryogenic exciter

    SciTech Connect

    Bray, James William; Garces, Luis Jose

    2012-03-13

    The disclosed technology is a cryogenic static exciter. The cryogenic static exciter is connected to a synchronous electric machine that has a field winding. The synchronous electric machine is cooled via a refrigerator or cryogen like liquid nitrogen. The static exciter is in communication with the field winding and is operating at ambient temperature. The static exciter receives cooling from a refrigerator or cryogen source, which may also service the synchronous machine, to selected areas of the static exciter and the cooling selectively reduces the operating temperature of the selected areas of the static exciter.

  9. Possible ground-state octupole deformation in /sup 229/Pa

    SciTech Connect

    Ahmad, I.; Gindler, J.E.; Betts, R.R.; Chasman, R.R.; Friedman, A.M.

    1982-12-13

    Evidence is presented for the occurrence of a (5/2)/sup + -/ parity doublet as the ground state of /sup 229/Pa, in agreement with a previous theoretical prediction. The doublet splitting energy is measured to be 0.22 +- 0.05 keV. The relation of this doublet to ground-state octupole deformation is discussed. .ID LV2109 .PG 1762 1764

  10. Octupole Deformation and Signature Inversion in 145Ba

    NASA Astrophysics Data System (ADS)

    Zhu, Sheng-jiang; Sakhaee, M.; Hamilton H., J.; Ramayya V., A.; Gan, Cui-yun; Zhu, Ling-yan; Yang, Li-ming; Long, Gui-lu; Pau, San-li; Babu R. S., B.; Hwang K., J.; Ma C., W.; Komicki, J.; Zhang Q., X.; Jones F., E.; Cole D., J.; Aryaeinejad, R.; Drigert W., M.; Rasmussen O., J.; Stoyer A., M.; Chu Y., S.; Gregorich E., K.; Mohar F., M.; Prussin G., S.; Lee Y., I.; Yu., Oganessian Ts.; Ter-Akopian M., G.; Daniel V., A.

    1999-10-01

    High spin states in neutron-rich odd-N 145Ba nucleus have been investigated from study of prompt γ-rays in spontaneous fission of 252Cf. The alternating parity bands are identified indicating octupole deformation with simplex quantum number s = -i. The ground state band shows signature splitting and inversion at low spin. These collective band structures exhibit the competition and co-existence between symmetric and asymmetric shapes.

  11. Octupole Magnet For Soft X Ray Magnetic Dichroism Experiments: Design and Performance

    SciTech Connect

    Arenholz, Elke; Prestemon, Soren O.

    2004-05-12

    An octupole magnet endstation for soft x ray magnetic dichroism measurements has been developed at the Advanced Light Source. The system consists of an eight pole electromagnet that surrounds a small vacuum chamber. The magnet provides fields up to 0.9 T that can be applied in any direction relative to the incoming x ray beam. High precision magnetic circular and linear dichroism spectra can be obtained reversing the magnetic field for each photon energy in an energy scan. Moreover, the field dependence of all components of the magnetization vector can be studied in detail by choosing various angles of x ray incidence while keeping the relative orientation of magnetic field and sample fixed.

  12. Octupole magnet for soft X ray magnetic dichroism experiments: Design and performance

    SciTech Connect

    Arenholz, Elke; Prestemon, Soren O.

    2003-08-24

    An octupole magnet endstation for soft x-ray magnetic dichroism measurements has been developed at the Advanced Light Source. The system consists of an eight pole electromagnet that surrounds a small vacuum chamber. The magnet provides fields up to 0.9 T that can be applied in any direction relative to the incoming x-ray beam. High precision magnetic circular and linear dichroism spectra can be obtained reversing the magnetic field for each photon energy in an energy scan. Moreover, the field dependence of all components of the magnetization vector can be studied in detail by choosing various angles of x-ray incidence while keeping the relative orientation of magnetic field and sample fixed.

  13. Octupole deformation in sup 221 Fr; E1 transition rates

    SciTech Connect

    Liang, C.F.; Peghaire, A. ); Sheline, R.K. )

    1990-07-10

    Experimental data following the alpha decay of{sup 225}Ac are interpreted in terms of a spectroscopy in {sup 221}Fr consistent with octupole deformation. However, the measured E1 transition probabilities suggest that the low lying bands in {sup 221}Fr are considerably more mixed than in nuclei with slightly higher mass number. It is suggested that this mixing of states in {sup 221}Fr is indicative of the partial collapse of Nilsson-like orbitals into more degenerate shell model orbitals.

  14. High. beta. studies in the Wisconsin Toroidal Octupole

    SciTech Connect

    Halle, J. H.; Kellman, A.; Post, R. S.; Prager, S. C.; Strait, E. J.; Zarnstorff, M. C.

    1980-09-01

    A wide range of MHD stable high ..beta.. plasmas is produced in the Wisconsin Levitated Octupole. At or near the single fluid regime we obtain, in the bad curvature region, ..beta.. = nk(T/sub e/ + T/sub i/)8..pi../B/sup 2/ approx. = 8%, twice the theoretical single fluid ballooning instability limit of 4%. We also obtain stable plasmas at ..beta.. approx. = 35%, 9 times the theoretical limit, in a regime in which both finite ion gyroradius and gyroviscosity effects are important.

  15. Two-Phonon Octupole Excitation in 146Gd

    SciTech Connect

    Caballero, L.; Rubio, B.; Algora, A.; Nacher, E.; Kleinheinz, P.; Dewald, A.; Fitzler, A.; Jolie, J.; Linnemann, A.; Moeller, O.; Gadea, A.; Julin, R.; Piiparinen, M.; Lunardi, S.; Menegazzo, R.; Yates, S.W.

    2005-11-21

    The excited states in 146Gd have been re-investigated with the 144Sm({alpha},2n) reaction using a modern Ge {gamma}-ray array including a polarimeter. Amongst the non-yrast states populated in this reaction we have identified the aligned 6+ member of the two-phonon octupole quartet from the observation of the E3 branching to the one phonon 3- state. Our results represent the first observation of a 6+{yields}3-{yields}0+ E3 cascade in an even-even nucleus.

  16. Two-Phonon Octupole Excitation in 146Gd

    SciTech Connect

    Caballero, L.; Rubio, B.; Nacher, E.; Kleinheinz, P.; Algora, A.; Blomqvist, J.; Dewald, A.; Fitzler, A.; Jolie, J.; Linnemann, A.; Moeller, O.; Gadea, A.; Julin, R.; Piiparinen, M.; Lunardi, S.; Menegazzo, R.; Yates, S. W.

    2006-04-26

    The excited states in 146Gd have been re-investigated with the 144Sm({alpha},2n) reaction using a modern Ge {gamma}-ray array including a polarimeter. Amongst the non-yrast states populated in this reaction we have identified the aligned 6+ member of the two-phonon octupole quartet from the observation of the E3 branching to the one phonon 3- state. Our results represent the first observation of a 6+{yields}3-{yields}0+ E3 cascade in an even-even nucleus.

  17. Proposed s =±1 octupole bands in 140Xe

    NASA Astrophysics Data System (ADS)

    Huang, Y.; Zhu, S. J.; Hamilton, J. H.; Wang, E. H.; Ramayya, A. V.; Xiao, Z. G.; Li, H. J.; Luo, Y. X.; Rasmussen, J. O.; Ter-Akopian, G. M.; Oganessian, Yu. Ts.

    2016-06-01

    Level structures of neutron-rich 140Xe nucleus have been reinvestigated by using a triple γ coincidence study from the spontaneous fission of 252Cf. Several new levels and transitions are identified. The previously observed s =+1 octupole band structure is confirmed and expanded. Another set of the Δ I =2 positive and negative parity bands connected by strong E 1 transitions is proposed as the s =-1 octupole band structure. Thus, the s =±1 doublet octupole bands are completed in 140Xe. The experimental B (E 1 )/B (E 2 ) branching ratios indicate that the octupole correlations in 140Xe are weak. The other characteristics of the s =±1 octupole bands have been discussed.

  18. Cryogenic Systems

    NASA Astrophysics Data System (ADS)

    Hosoyama, Kenji

    2002-02-01

    In this lecture we discuss the principle of method of cooling to a very low temperature, i.e. cryogenic. The "gas molecular model" will be introduced to explain the mechanism cooling by the expansion engine and the Joule-Thomson expansion valve. These two expansion processes are normally used in helium refrigeration systems to cool the process gas to cryogenic temperature. The reverse Carnot cycle will be discussed in detail as an ideal refrigeration cycle. First the fundamental process of liquefaction and refrigeration cycles will be discussed, and then the practical helium refrigeration system. The process flow of the system and the key components; -compressor, expander, and heat exchanger- will be discussed. As an example of an actual refrigeration system, we will use the cryogenic system for the KEKB superconducting RF cavity. We will also discuss the liquid helium distribution system, which is very important, especially for the cryogenic systems used in accelerator applications. 1 Principles of Cooling and Fundamental Cooling Cycle 2 Expansion engine, Joule-Thomson expansion, kinetic molecular theory, and enthalpy 3 Liquefaction Systems 4 Refrigeration Systems 5 Practical helium liquefier/refrigeration system 6 Cryogenic System for TRISTAN Superconducting RF Cavity

  19. RHIC cryogenics

    NASA Astrophysics Data System (ADS)

    Iarocci, M. A.; Brown, D.; Sondericker, J.; Wu, K. C.; Benson, J.; Farah, Y.; Lac, C.; Morgillo, A.; Nicoletti, A.; Quimby, E.; Rank, J.; Rehak, M.; Werner, A.

    2003-03-01

    An integrated helium cryogenic system was designed with the specific performance goal of cooling and refrigerating the cryogenic magnets to below their nominal operating temperature. These magnets make up the steering and focusing elements for the Relativistic Heavy Ion Collider (RHIC). In addition to meeting the accelerator demands, reliability, flexibility, safety, and ease of operation were key considerations during the design phase of the project. The refrigerator, with a capacity of 25 kW at about 4 K, was originally designed to match the load for the Colliding Beam Accelerator Project. The existing refrigerator, along with its complimentary warm compressor system was reconfigured slightly to meet the cooling process cycle design for RHIC. The original VAX based process control system was also adapted for RHIC, and later expanded upon to integrate a new programmable logic controller based ring resident control system, hence forming a common system to monitor and control all cryogenic components.

  20. Octupole deformation properties of the Barcelona-Catania-Paris energy density functionals

    SciTech Connect

    Robledo, L. M.; Baldo, M.; Schuck, P.; Vinas, X.

    2010-03-15

    We discuss the octupole deformation properties of the recently proposed Barcelona-Catania-Paris (BCP) energy density functionals for two sets of isotopes, those of radium and barium, in which it is believed that octupole deformation plays a role in the description of the ground state. The analysis is carried out in the mean field framework (Hartree-Fock-Bogoliubov approximation) by using the axially symmetric octupole moment as a constraint. The main ingredients entering the octupole collective Hamiltonian are evaluated and the lowest-lying octupole eigenstates are obtained. In this way we restore, in an approximate way, the parity symmetry spontaneously broken by the mean field and also incorporate octupole fluctuations around the ground-state solution. For each isotope the energy of the lowest lying 1{sup -} state and the B(E1) and B(E3) transition probabilities have been computed and compared to both the experimental data and the results obtained in the same framework with the Gogny D1S interaction, which are used here as a well-established benchmark. Finally, the octupolarity of the configurations involved in the way down to fission of {sup 240}Pu, which is strongly connected to the asymmetric fragment mass distribution, is studied. We confirm with this thorough study the suitability of the BCP functionals to describe octupole-related phenomena.

  1. Cryogenic shutter

    NASA Astrophysics Data System (ADS)

    Barney, Richard D.; Magner, Thomas J.

    1992-07-01

    A magnetically operated shutter mechanism is provided that will function in cryogenic or cryogenic zero gravity environments to selectively block radiation such as light from passing through a window to a target object such as a mirror or detector located inside a cryogenic container such as a dewar. The mechanism includes a shutter paddle blade that is moved by an electromagnetically actuated torquing device between an open position where the target object is exposed to ambient radiation or light and a closed position where the shutter paddle blade shields the ambient radiation or light from the target object. The purpose of the shuttering device is to prevent the mirror or other target object from being directly exposed to radiation passing through the window located on the side wall of the dewar, thereby decreasing or eliminating any temperature gradient that would occur within the target object due to exposure to the radiation. A special nylon bearing system is utilized to prevent the device from binding during operation and the paddle blade is also thermally connected to a reservoir containing cryogen to further reduce the internal temperature.

  2. Plasma resistivity measurements in the Wisconsin levitated octupole

    SciTech Connect

    Brouchous, D. A.

    1980-11-01

    Resistivity measurements parallel to the magnetic field were made on gun injected plasmas ranging in density from 10/sup 9/cm/sup -3/ to 10/sup 1/parallelcm/sup -3/ in the Wisconsin levitated octupole with toroidal and poloidal magnetic fields. The 10/sup 9/cm/sup -3/ plasma was collisionless with lambda/sub mfp/ > 100 mirror lengths, had T/sub e/ = 10 eV, T/sub i/ = 30 eV and was found to have anomalous resistivity scaling like eta = ..sqrt..T/sub e//n/sub e/ when E/sub parallel/ > E/su c/ is the Dreicer critical field. The 10/sup 12/cm/sup -3/ plasma was collisional with lambda/sub mfp/ < mirror length, had T/sub e/ = T/sub i/ approx. = .2 eV and was found to have Spitzer resistivity when E/sub parallel/ < E/sub c/.

  3. Search for two-phonon octupole excitations in 146Gd

    NASA Astrophysics Data System (ADS)

    Orce, J. N.; Kumar Raju, M.; Khumalo, N. A.; Dinoko, T. S.; Jones, P.; Bark, R. A.; Lawrie, E. A.; Majola, S. N. T.; Robledo, L. M.; Rubio, B.; Wiedeking, M.; Easton, J.; Khaleel, E. A.; Kheswa, B. V.; Kheswa, N.; Herbert, M. S.; Lawrie, J. J.; Masiteng, P. L.; Nchodu, M. R.; Ndayishimye, J.; Negi, D.; Noncolela, S. P.; Ntshangase, S. S.; Papka, P.; Roux, D. G.; Shirinda, O.; Sithole, P. S.; Yates, S. W.

    2016-06-01

    The low-spin structure of the nearly spherical nucleus 146Gd was studied using the 144Sm(4He, 2n) fusion-evaporation reaction. High-statistics γ - γ coincidence measurements were performed at iThemba LABS with 7× 109 γ- γ coincidence events recorded. Gated γ-ray energy spectra show evidence for the 6+2 → 3-1 → 0+1 cascade of E3 transitions in agreement with recent findings by Caballero and co-workers, but with a smaller branching ratio of I_{γ} = 4.7(10) for the 6+2 → 3-1 1905.1 keV γ ray. Although these findings may support octupole vibrations in spherical nuclei, sophisticated beyond mean-field calculations including angular-momentum projection are required to interpret in an appropriate way the available data due to the failure of the rotational model assumptions in this nucleus.

  4. First hyperpolarizabilities of 1,3,5-tricyanobenzene derivatives: origin of larger beta values for the octupoles than for the dipoles.

    PubMed

    Lee, Sang Hae; Park, Jo Ryoung; Jeong, Mi-Yun; Kim, Hwan Myung; Li, Shaojun; Song, Jongwon; Ham, Sihyun; Jeon, Seung-Joon; Cho, Bong Rae

    2006-01-16

    A series of donor-acceptor substituted stilbene and diphenylacetylene derivatives and their octupolar analogues have been synthesized and the linear and nonlinear optical properties (beta) studied by both experiments and theoretical calculation. The lambda(max) of the dipoles increases with the conjugation length and is always larger when the C=C bond is used, instead of the C[triple bond]C bond, as the conjugation bridge. Although the lambda(max) values of the octupoles show no clear trend, they are much larger than those of the dipoles. The beta(0) values of the dipoles increase with conjugation length and as the conjugation bridge is changed from the C[triple bond]C to C=C bond. This increase is accompanied by an increase in either lambda(max) or the oscillator strength. Similarly, the beta(0) values of the octupoles increase with the conjugation length and with a change in the donor in the order: NEt2 < N(i-amyl)Ph < NPh2. Moreover, beta(yyy)/beta(zzz) ratios are in the range of 1.6-3.9 and decrease with the conjugation length. Beta values calculated by the finite-field and sum-over-states methods are in good agreement with the experimental data. Also, there is a parallel relationship between the calculated beta values and bond length alternation (BLA). From these results, the origin of the larger beta values for octupoles than for dipoles is assessed. PMID:16323225

  5. Stirling cycle cryogenic cooler

    NASA Astrophysics Data System (ADS)

    Gasser, M. G.; Sherman, A.; Studer, P. A.; Daniels, A.; Goldowsky, M. P.

    1983-06-01

    A long lifetime Stirling cycle cryogenic cooler particularly adapted for space applications is described. It consists of a compressor section centrally aligned end to end with an expansion section, and respectively includes a reciprocating compressor piston and displacer radially suspended in interconnecting cylindrical housings by active magnetic bearings and has adjacent reduced clearance regions so as to be in noncontacting relationship therewith and wherein one or more of these regions operate as clearance seals. The piston and displacer are reciprocated in their housings by linear drive motors to vary the volume of respectively adjacent compression and expansion spaces which contain a gaseous working fluid and a thermal regenerator to effect Stirling cycle cryogenic cooling.

  6. Stirling cycle cryogenic cooler

    NASA Technical Reports Server (NTRS)

    Gasser, M. G.; Sherman, A.; Studer, P. A.; Daniels, A.; Goldowsky, M. P. (Inventor)

    1983-01-01

    A long lifetime Stirling cycle cryogenic cooler particularly adapted for space applications is described. It consists of a compressor section centrally aligned end to end with an expansion section, and respectively includes a reciprocating compressor piston and displacer radially suspended in interconnecting cylindrical housings by active magnetic bearings and has adjacent reduced clearance regions so as to be in noncontacting relationship therewith and wherein one or more of these regions operate as clearance seals. The piston and displacer are reciprocated in their housings by linear drive motors to vary the volume of respectively adjacent compression and expansion spaces which contain a gaseous working fluid and a thermal regenerator to effect Stirling cycle cryogenic cooling.

  7. CRYOGENIC MAGNETS

    DOEpatents

    Post, R.F.; Taylor, C.E.

    1963-05-21

    A cryogenic magnet coil is described for generating magnetic fields of the order of 100,000 gauss with a minimum expenditure of energy lost in resistive heating of the coil inductors and energy lost irreversibly in running the coil refrigeration plant. The cryogenic coil comprises a coil conductor for generating a magnetic field upon energization with electrical current, and refrigeration means disposed in heat conductive relation to the coil conductor for cooling to a low temperature. A substantial reduction in the power requirements for generating these magnetic fields is attained by scaling the field generating coil to large size and particular dimensions for a particular conductor, and operating the coil at a particular optimum temperature commensurate with minimum overall power requirements. (AEC)

  8. Heart-shaped nuclei: Condensation of rotational-aligned octupole phonons

    SciTech Connect

    Frauendorf, S.

    2008-02-15

    The strong octupole correlations in the mass region A{approx_equal}226 are interpreted as rotation-induced condensation of octupole phonons having their angular momentum aligned with the rotational axis. Discrete phonon energy and parity conservation generate oscillations of the energy difference between the lowest rotational bands with positive and negative parity. Anharmonicities tend to synchronize the rotation of the condensate and the quadrupole shape of the nucleus forming a rotating heart shape.

  9. Octupole correlations in the 144Ba nucleus described with symmetry-conserving configuration-mixing calculations

    NASA Astrophysics Data System (ADS)

    Bernard, Rémi N.; Robledo, Luis M.; Rodríguez, Tomás R.

    2016-06-01

    We study the interplay of quadrupole and octupole degrees of freedom in the structure of the isotope 144Ba. A symmetry-conserving configuration-mixing method (SCCM) based on a Gogny energy density functional (EDF) has been used. The method includes particle number, parity, and angular momentum restoration as well as axial quadrupole and octupole shape mixing within the generator coordinate method. Predictions both for excitation energies and electromagnetic transition probabilities are in good agreement with the most recent experimental data.

  10. Influence of the octupole mode on nuclear high-K isomeric properties

    NASA Astrophysics Data System (ADS)

    Minkov, Nikolay; Walker, Phil

    2014-05-01

    The influence of quadrupole-octupole deformations on the energy and magnetic properties of high-K isomeric states in even-even actinide (U, Pu, Cm, Fm, No), rare-earth (Nd, Sm and Gd), and superheavy (^{270}\\text{Ds}) nuclei is examined within a deformed shell model with pairing interaction. The neutron two-quasiparticle (2qp) isomeric energies and magnetic dipole moments are calculated over a wide range in the plane of quadrupole and octupole deformations. In most cases the magnetic moments exhibit a pronounced sensitivity to the octupole deformation. At the same time, the calculations outline three different groups of nuclei: with pronounced, shallow, and missing minima in the 2qp energy surfaces with respect to the octupole deformation. The result indicates regions of nuclei with octupole softness as well as with possible octupole deformation in the high-K isomeric states. These findings show the need for further theoretical analysis as well as of detailed experimental measurements of magnetic moments in heavy deformed nuclei.

  11. Observation of the Nuclear Magnetic Octupole Moment of 137Ba+

    NASA Astrophysics Data System (ADS)

    Hoffman, Matthew

    Single trapped ions are ideal systems in which to test atomic physics at high precision, which can in turn be used for searches for violations of fundamental symmetries and physics beyond the standard model, in addition to quantum computation and a number of other applications. The ion is confined in ultra-high vacuum, is laser cooled to mK temperatures, and kept well isolated from the environment which allows these experimental efforts. In this thesis, a few diagnostic techniques will be discussed, covering a method to measure the linewidth of a narrowband laser in the presence of magnetic field noise, as well as a procedure to measure the ion's temperature using such a narrowband laser. This work has led to two precision experiments to measure atomic structure in 138Ba+, and 137Ba+ discussed here. First, employing laser and radio frequency spectroscopy techniques in 138Ba+, we measured the Lande- gJ factor of the 5D5/2 level at the part-per-million level, the highest precision to date. Later, the development of apparatus to efficiently trap and laser cool 137Ba+ has enabled a measurement of the hyperfine splittings of the 5D3/2 manifold, culminating in the observation of the nuclear magnetic octupole moment of 137Ba+.

  12. Stable and Vibrational Octupole Modes in Mo, Xe, Ba, La, Ce and Nd

    SciTech Connect

    Gore, P.M.; Hamilton, J.H.; Hwang, J.K.; Jones, E.F.; Peker, L.K.; Ramayya, A.V.; Zhang, X.Q.; Zhu, S.J.

    1998-05-18

    Evidence is presented for stable octupole deformation in neutron-rich nuclei, bounded by Z = 54-58 and N = 85-92. To either side of this region negative parity bands built on more vibrational type octupole modes are observed in {sup 140}Ba and {sup 152,154}Nd. The largest stable octupole deformation ({beta}{sub s} {approximately} 0.1) is found in {sup 144}Ba{sub as}. The theoretically predicted quenching ({beta}{sub s} {approximately} 0) of stable octupole deformation at higher spins is found in {sup 140}Ba. There is good agreement between theory and experiment for the strongly varying electric dipole moments as a function of mass for {sup 142-141}Ba. In odd-A {sup 142}Ba and odd-Z {sup 140}La, we observe parity doublets, two pairs of positive and negative parity bands with opposite spins. In {sup 145}La a strong coupled ground band with symmetric shape coexists with the asymmetric octupole shape which stabilizes above about spin 19/2. In {sup 145,147}La a strong reduction in E2 strength around 25/2 from band crossing is observed. The isotope {sup 109}Mo was identified and a new region of stable uctpole deformation is identified in {sup 107,108}Mo centered around N = 64-66 as earlier predicted. This is the first case of stable uctpole deformation involving only one pair of orbitals.

  13. CRYOGENIC DEWAR

    DOEpatents

    Chamberlain, W.H.; Maseck, H.E.

    1964-01-28

    This patent relates to a dewar for storing cryogenic gase and is of the type having aii inner flask surrounded by a vacuum jacket and having a vent spout through which evaporating gas escapes. Heretofore substantial gas loss has resulted from the radiation of heat towards the flask from the warmer outer elements of the dewar. In this invention, the mask is surrounded by a thermally conducting shield which is disposed in the vacuum space between the flask and the outer elements of the dewar. The shield contacts only the vent spout, which is cooled by the evaporating gas, and thus is maintained at a temperature very close to that of the flask itself. Accordingly, heat radiated toward the flask is intercepted and conducted to the evaporating gas rather than being re-radiated towards the hask. In a liquid helium dewar of typical configniration the mention reduces the boil-off rate by approximately one-half.(AEC)

  14. Ilc Cryogenic Systems Reference Design

    NASA Astrophysics Data System (ADS)

    Peterson, T. J.; Geynisman, M.; Klebaner, A.; Parma, V.; Tavian, L.; Theilacker, J.

    2008-03-01

    A Global Design Effort (GDE) began in 2005 to study a TeV scale electron-positron linear accelerator based on superconducting radio-frequency (RF) technology, called the International Linear Collider (ILC). In early 2007, the design effort culminated in a reference design for the ILC, closely based on the earlier TESLA design. The ILC will consist of two 250 GeV linacs, which provide positron-electron collisions for high energy physics research. The particle beams will be accelerated to their final energy in superconducting niobium RF cavities operating at 2 kelvin. At a length of about 12 km each, the main linacs will be the largest cryogenic systems in the ILC. Positron and electron sources, damping rings, and beam delivery systems will also have a large number and variety of other superconducting RF cavities and magnets, which require cooling at liquid helium temperatures. Ten large cryogenic plants with 2 kelvin refrigeration are envisioned to cool the main linacs and the electron and positron sources. Three smaller cryogenic plants will cool the damping rings and beam delivery system components predominately at 4.5 K. This paper describes the cryogenic systems concepts for the ILC.

  15. ILC cryogenic systems reference design

    SciTech Connect

    Peterson, T.J.; Geynisman, M.; Klebaner, A.; Theilacker, J.; Parma, V.; Tavian, L.; /CERN

    2008-01-01

    A Global Design Effort (GDE) began in 2005 to study a TeV scale electron-positron linear accelerator based on superconducting radio-frequency (RF) technology, called the International Linear Collider (ILC). In early 2007, the design effort culminated in a reference design for the ILC, closely based on the earlier TESLA design. The ILC will consist of two 250 GeV linacs, which provide positron-electron collisions for high energy physics research. The particle beams will be accelerated to their final energy in superconducting niobium RF cavities operating at 2 kelvin. At a length of about 12 km each, the main linacs will be the largest cryogenic systems in the ILC. Positron and electron sources, damping rings, and beam delivery systems will also have a large number and variety of other superconducting RF cavities and magnets, which require cooling at liquid helium temperatures. Ten large cryogenic plants with 2 kelvin refrigeration are envisioned to cool the main linacs and the electron and positron sources. Three smaller cryogenic plants will cool the damping rings and beam delivery system components predominately at 4.5 K. This paper describes the cryogenic systems concepts for the ILC.

  16. Cryogenic Flow Sensor

    NASA Technical Reports Server (NTRS)

    Justak, John

    2010-01-01

    An acousto-optic cryogenic flow sensor (CFS) determines mass flow of cryogens for spacecraft propellant management. The CFS operates unobtrusively in a high-pressure, high-flowrate cryogenic environment to provide measurements for fluid quality as well as mass flow rate. Experimental hardware uses an optical plane-of-light (POL) to detect the onset of two-phase flow, and the presence of particles in the flow of water. Acousto-optic devices are used in laser equipment for electronic control of the intensity and position of the laser beam. Acousto-optic interaction occurs in all optical media when an acoustic wave and a laser beam are present. When an acoustic wave is launched into the optical medium, it generates a refractive index wave that behaves like a sinusoidal grating. An incident laser beam passing through this grating will diffract the laser beam into several orders. Its angular position is linearly proportional to the acoustic frequency, so that the higher the frequency, the larger the diffracted angle. If the acoustic wave is traveling in a moving fluid, the fluid velocity will affect the frequency of the traveling wave, relative to a stationary sensor. This frequency shift changes the angle of diffraction, hence, fluid velocity can be determined from the diffraction angle. The CFS acoustic Bragg grating data test indicates that it is capable of accurately determining flow from 0 to 10 meters per second. The same sensor can be used in flow velocities exceeding 100 m/s. The POL module has successfully determined the onset of two-phase flow, and can distinguish vapor bubbles from debris.

  17. Possible octupole deformation in Cs and Ba nuclei from their differential radii

    SciTech Connect

    Sheline, R.K.; Jain, A.K.; Jain, K.

    1988-12-01

    The odd-even staggering of the differential radii of Fr and Ra and the Cs and Ba nuclei is compared. This staggering is inverted in the region of known octupole deformation in the Fr and Ra nuclei. The normal staggering is eliminated in the Cs nuclei and attenuated in the Ba nuclei for neutron numbers 85--88. This fact is used to suggest the possible existence of octupole deformation and its neutron number range in the Cs and Ba nuclear ground states.

  18. Collective states of odd nuclei in a model with quadrupole-octupole degrees of freedom

    SciTech Connect

    Minkov, N. Drenska, S. B.; Yotov, P.; Bonatsos, D. Scheid, W.

    2007-08-15

    We apply the collective axial quadrupole-octupole Hamiltonian to describe the rotation-vibration motion of odd nuclei with Coriolis coupling between the even-even core and the unpaired nucleon.We consider that the core oscillates coherently with respect to the quadrupole and octupole axialdeformation variables. The coupling between the core and the unpaired nucleon provides a split paritydoublet structure of the spectrum. The formalism successfully reproduces the parity-doublet splitting in a wide range of odd-A nuclei. It provides model estimations for the third angular-momentum projection K on the intrinsic symmetry axis and the related intrinsic nuclear structure.

  19. Influence of octupole interactions on the behavior of negative-parity states at low spins

    SciTech Connect

    Sitdikov, A. S. Safarov, R. Kh.; Kvasil, J.

    2006-12-15

    The energies of negative-parity levels based on two-particle states exhibit a nonlinear behavior at low spins versus the core-rotation energy because the alignment process has not yet been completed for them. This behavior of negative-parity levels in the low-spin region is satisfactorily described upon the inclusion of octupole-octupole interactions. This is demonstrated within the rotational model involving the Coriolis mixing of states for the even-even isotopes {sup 162-168}Hf.

  20. Specifications of the octupole magnets required for the ATF2 ultra-low ß* lattice

    SciTech Connect

    Marin, E.; Modena, M.; Tauchi, T.; Terunuma, N.; Tomas, R.; White, G.R.; /SLAC

    2014-05-28

    The Accelerator Test Facility 2 (ATF2) aims to test the novel chromaticity correction for higher chromaticity lattices as the one of CLIC. To this end the ATF2 ultra-low ß* lattice is designed to vertically focus the beam at the focal point or usually referred to as interaction point (IP), down to 23 nm. However when the measured multipole components of the ATF2 magnets are considered in the simulations, the evaluated spot sizes at the IP are well above the design value. The designed spot size is effectively recovered by inserting a pair of octupole magnets. In this note we address the technical specifications required for these octupole magnets.

  1. Energy Efficient Cryogenics

    NASA Technical Reports Server (NTRS)

    Meneghelli, Barry J.; Notardonato, William; Fesmire, James E.

    2016-01-01

    The Cryogenics Test Laboratory, NASA Kennedy Space Center, works to provide practical solutions to low-temperature problems while focusing on long-term technology targets for the energy-efficient use of cryogenics on Earth and in space.

  2. Cryogenic immersion microscope

    DOEpatents

    Le Gros, Mark; Larabell, Carolyn A.

    2010-12-14

    A cryogenic immersion microscope whose objective lens is at least partially in contact with a liquid reservoir of a cryogenic liquid, in which reservoir a sample of interest is immersed is disclosed. When the cryogenic liquid has an index of refraction that reduces refraction at interfaces between the lens and the sample, overall resolution and image quality are improved. A combination of an immersion microscope and x-ray microscope, suitable for imaging at cryogenic temperatures is also disclosed.

  3. Octupole Resonance in the AGS at High Intensity: A SIMBAD study

    SciTech Connect

    Luccio, A.U.; D'Imperio, N.L.

    2005-06-08

    We studied the Octupole (Montague) resonance in the AGS, in its high intensity mode, by tracking with the PIC code SIMBAD. We calculated, turn-by-turn, the betatron tune footprint from the eigenvalues of the one-turn matrix. We show that one should exercise particular caution when the betatron tunes are close together, since the matrix gives ambiguous results at the resonance.

  4. Betatron tune spread generation and differential chromaticity control by octupole families at Tevatron

    SciTech Connect

    Ivanov, P.M.; Alexahin, Y.; Annala, J.; Lebedev, V.A.; /Fermilab

    2005-05-01

    Existing Tevatron octupoles have been rearranged into four functional families. Two of these families generate betatron tune spreads in the vertical and horizontal planes whereas the other two control the differential chromaticity between the proton and antiproton helices. The calculated effect on the tunes and chromaticity is compared with direct measurements. Analytical formulas for betatron tune distribution functions are presented.

  5. Octupole deformation in 144,146Ba measured by Coulomb excitation of radioactive beams

    NASA Astrophysics Data System (ADS)

    Bucher, Brian; Zhu, Shaofei; ANL, LBNL, LLNL, Rochester, Florida State, Liverpool, Maryland, Notre Dame, Ohio, W. Scotland Collaboration

    2015-10-01

    The exotic, neutron-rich 144Ba (t1 / 2 = 11.5 s) and 146Ba (t1 / 2 = 2.2 s) nuclei are expected to exhibit some of the strongest octupole correlations in A < 200 systems. Up to now, evidence for such strong octupole correlations has been inferred from observations of low-lying negative-parity states and from the interleaving of positive- and negative-parity levels in the ground-state band. However, the E1 transition strengths are very different in these two nuclei, with two orders of magnitude reduction in 146Ba. In this experiment, we measure the octupole strength directly by Coulomb excitation of post-accelerated 144,146Ba beams produced at CARIBU using CHICO2 and GRETINA. In 144Ba, we found B(E3;3 -->0) = 48(-34+ 25) W.u., a value considerably larger than theoretical predictions, while preliminary results for 146Ba are also indicative of strong octupole collectivity. The experimental conditions, the analysis, and the results from these challenging new measurements will be presented. This work is supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357 (ANL), DE-AC02-05CH11231 (LBNL, GRETINA), DOE DE-AC52-07NA27344 (LLNL), and NSF.

  6. Direct evidence of octupole deformation in neutron-rich 144Ba

    DOE PAGESBeta

    Bucher, B.; Zhu, S.; Wu, C. Y.; Janssens, R. V. F.; Cline, D.; Hayes, A. B.; Albers, M.; Ayangeakaa, A. D.; Butler, P. A.; Campbell, C. M.; et al

    2016-03-17

    Here, the neutron-rich nucleus 144Ba (t1/2 = 11.5 s) is expected to exhibit some of the strongest octupole correlations among nuclei with mass numbers A less than 200. Until now, indirect evidence for such strong correlations has been inferred from observations such as enhanced E1 transitions and interleaving positive- and negative-parity levels in the ground-state band. In this experiment, the octupole strength was measured directly by sub-barrier, multistep Coulomb excitation of a post-accelerated 650-MeV 144Ba beam on a 1.0–mg/cm2 208Pb target. The measured value of the matrix element, < 31–∥M(E3)∥01+ >= 0.65(+17–23) eb3/2, corresponds to a reduced B(E3) transition probabilitymore » of 48(+25–34) W.u. This result represents an unambiguous determination of the octupole collectivity, is larger than any available theoretical prediction, and is consistent with octupole deformation.« less

  7. Direct Evidence of Octupole Deformation in Neutron-Rich ^{144}Ba.

    PubMed

    Bucher, B; Zhu, S; Wu, C Y; Janssens, R V F; Cline, D; Hayes, A B; Albers, M; Ayangeakaa, A D; Butler, P A; Campbell, C M; Carpenter, M P; Chiara, C J; Clark, J A; Crawford, H L; Cromaz, M; David, H M; Dickerson, C; Gregor, E T; Harker, J; Hoffman, C R; Kay, B P; Kondev, F G; Korichi, A; Lauritsen, T; Macchiavelli, A O; Pardo, R C; Richard, A; Riley, M A; Savard, G; Scheck, M; Seweryniak, D; Smith, M K; Vondrasek, R; Wiens, A

    2016-03-18

    The neutron-rich nucleus ^{144}Ba (t_{1/2}=11.5  s) is expected to exhibit some of the strongest octupole correlations among nuclei with mass numbers A less than 200. Until now, indirect evidence for such strong correlations has been inferred from observations such as enhanced E1 transitions and interleaving positive- and negative-parity levels in the ground-state band. In this experiment, the octupole strength was measured directly by sub-barrier, multistep Coulomb excitation of a post-accelerated 650-MeV ^{144}Ba beam on a 1.0-mg/cm^{2} ^{208}Pb target. The measured value of the matrix element, ⟨3_{1}^{-}∥M(E3)∥0_{1}^{+}⟩=0.65(+17/-23) eb^{3/2}, corresponds to a reduced B(E3) transition probability of 48(+25/-34)  W.u. This result represents an unambiguous determination of the octupole collectivity, is larger than any available theoretical prediction, and is consistent with octupole deformation. PMID:27035298

  8. Direct Evidence of Octupole Deformation in Neutron-Rich 144Ba

    NASA Astrophysics Data System (ADS)

    Bucher, B.; Zhu, S.; Wu, C. Y.; Janssens, R. V. F.; Cline, D.; Hayes, A. B.; Albers, M.; Ayangeakaa, A. D.; Butler, P. A.; Campbell, C. M.; Carpenter, M. P.; Chiara, C. J.; Clark, J. A.; Crawford, H. L.; Cromaz, M.; David, H. M.; Dickerson, C.; Gregor, E. T.; Harker, J.; Hoffman, C. R.; Kay, B. P.; Kondev, F. G.; Korichi, A.; Lauritsen, T.; Macchiavelli, A. O.; Pardo, R. C.; Richard, A.; Riley, M. A.; Savard, G.; Scheck, M.; Seweryniak, D.; Smith, M. K.; Vondrasek, R.; Wiens, A.

    2016-03-01

    The neutron-rich nucleus 144Ba (t1 /2=11.5 s ) is expected to exhibit some of the strongest octupole correlations among nuclei with mass numbers A less than 200. Until now, indirect evidence for such strong correlations has been inferred from observations such as enhanced E 1 transitions and interleaving positive- and negative-parity levels in the ground-state band. In this experiment, the octupole strength was measured directly by sub-barrier, multistep Coulomb excitation of a post-accelerated 650-MeV 144Ba beam on a 1.0 -mg /cm2 208Pb target. The measured value of the matrix element, ⟨31 -∥M (E 3 )∥01 +⟩=0.65 (+17/-23) e b3 /2, corresponds to a reduced B (E 3 ) transition probability of 48 (+25/-34) W .u . This result represents an unambiguous determination of the octupole collectivity, is larger than any available theoretical prediction, and is consistent with octupole deformation.

  9. Symmetry of the CMB sky as a new test of its statistical isotropy. Non cosmological octupole?

    SciTech Connect

    Naselsky, P.; Hansen, M.; Kim, J. E-mail: kirstejn@nbi.dk

    2011-09-01

    In this article we propose a novel test for statistical anisotropy of the CMB ΔT( n-circumflex = (θ,φ)). The test is based on the fact, that the Galactic foregrounds have a remarkably strong symmetry with respect to their antipodal points with respect to the Galactic plane, while the cosmological signal should not be symmetric or asymmetric under these transitions. We have applied the test for the octupole component of the WMAP ILC 7 map, by looking at a{sub 3,1} and a{sub 3,3}, and their ratio to a{sub 3,2} both for real and imaginary values. We find abnormal symmetry of the octupole component at the level of 0.58%, compared to Monte Carlo simulations. By using the analysis of the phases of the octupole we found remarkably strong cross-correlations between the phases of the kinematic dipole and the ILC 7 octupole, in full agreement with previous results. We further test the multipole range 2 < l < 100, by investigating the ratio between the l+m = even and l+m = odd parts of power spectra. We compare the results to simulations of a Gaussian random sky, and find significant departure from the statistically isotropic and homogeneous case, for a very broad range of multipoles. We found that for the most prominent peaks of our estimator, the phases of the corresponding harmonics are coherent with phases of the octupole. We believe, our test would be very useful for detections of various types of residuals of the foreground and systematic effects at a very broad range of multipoles 2 ≤ l ≤ 1500−3000 for the forthcoming PLANCK CMB map, before any conclusions about primordial non-Gaussianity and statistical anisotropy of the CMB.

  10. Anharmonicity of the excited octupole band in actinides using supersymmetric quantum mechanics

    NASA Astrophysics Data System (ADS)

    Jolos, R. V.; von Brentano, P.; Casten, R. F.

    2013-09-01

    Background: Low-lying octupole collective excitations play an important role in the description of the structure of nuclei in the actinide region. Ground state alternating parity rotational bands combining both positive and negative parity states are known in several nuclei. However, only recently it has been discovered in 240Pu an excited positive parity rotational band having an octupole nature and demonstrating strong anharmonicity of the octupole motion in the band head energies.Purpose: To suggest a model describing both ground state and excited alternating parity bands, which includes a description of the anharmonic effects in the bandhead excitation energies and can be used to predict the energies of the excited rotational bands of octupole nature and the E1 transition probabilities.Methods: The mathematical technique of the supersymmetric quantum mechanics with a collective Hamiltonian depending only on the octupole collective variable which keeps axial symmetry is used to describe the ground state and excited alternating parity rotational bands.Results: The excitation energies of the states belonging to the lowest negative parity and the excited positive parity bands are calculated for 232Th, 238U, and 240Pu. The E1 transition matrix elements are also calculated for 240Pu.Conclusions: It is shown that the suggested model describes the excitation energies of the states of the lowest negative parity band with the accuracy around 10 keV. The anharmonicity in the bandhead energy of the excited positive parity band is described also. The bandhead energy of the excited positive parity band is described with the accuracy around 100 keV.

  11. Cryogenic wind tunnels. III

    NASA Technical Reports Server (NTRS)

    Kilgore, Robert A.

    1987-01-01

    Specific problems pertaining to cryogenic wind tunnels, including LN(2) injection, GN(2) exhaust, thermal insulation, and automatic control are discussed. Thermal and other physical properties of materials employed in these tunnels, properties of cryogenic fluids, storage and transfer of liquid nitrogen, strength and toughness of metals and nonmetals at low temperatures, and material procurement and qualify control are considered. Safety concerns with cryogenic tunnels are covered, and models for cryogenic wind tunnels are presented, along with descriptions of major cryogenic wind-tunnel facilities the United States, Europe, and Japan. Problems common to wind tunnels, such as low Reynolds number, wall and support interference, and flow unsteadiness are outlined.

  12. Octupole Deformation Bands of πh11/2 in Neutron-Rich 145,147La Nuclei

    NASA Astrophysics Data System (ADS)

    Zhu, Sheng-jiang; S, Zhu J.; Wang, Mu-ge; J, Hamilton H.; A, Ramayya V.; B, Babu R. S.; W, Ma C.; Long, Gui-lu; Zhu, Ling-yan; Li, Ming; A, Sakhaee; Gan, Cui-yun; Yang, Li-ming; J, Komicki; J, Cole D.; R, Aryaeinejad; M, Drigert W.; J, Rasmussen O.; M, Stoyer A.; S, Chu Y.; K, Gregorich E.; M, Mohar F.; S, Prussin G.; I, Lee Y.; Yu, Oganessian Ts; G, Ter-Akopian M.; A, Daniel V.

    1999-03-01

    Octupole deformation bands built on πh11/2 orbital in neutron-rich odd-Z 145,147La nuclei have been investigated by measuring the prompt γ-rays emitted from the 252Cf source. The alternating parity band structures and strong E1 transitions observed between negative- and positive-parity bands in both nuclei indicate the octupole deformation enhanced by the h11/2 single proton coupling. According to observed energy displacements the octupole deformation becomes stable at the intermediate spin states.

  13. Coulomb Excitation with CARIBU Beams: Octupole Strength in 144Ba Measured with GRETINA and CHICO2

    NASA Astrophysics Data System (ADS)

    Bucher, Brian; Zhu, Shaofei; ANL, LBNL, LLNL, Rochester, Florida St, Liverpool, Maryland, Notre Dame, Ohio,; W. Scotland Collaboration

    2014-09-01

    The neutron-rich barium isotopes sit in one of the few mass regions on the nuclear chart observed to display octupole correlations. These isotopes are challenging to study since they lie far from stability and are thus difficult to produce in large quantities. In particular, this region is interesting for studying the evolution of octupole correlations since the enhancement of the E1 strength drops by an order of magnitude from 144Ba to 146Ba, where shell corrections appear to play a significant role. To provide unambiguous insight into the octupole correlations, B(E3) strengths have been measured using Coulomb excitation of 144Ba beams at 650 MeV on a 1 mg/cm2 208Pb target. This experiment represents the first successful measurement utilizing re-accelerated CARIBU beams combined with the γ-ray tracking array GRETINA and the auxiliary charged-particle detector CHICO2. Preliminary results from the experiment will be presented. The neutron-rich barium isotopes sit in one of the few mass regions on the nuclear chart observed to display octupole correlations. These isotopes are challenging to study since they lie far from stability and are thus difficult to produce in large quantities. In particular, this region is interesting for studying the evolution of octupole correlations since the enhancement of the E1 strength drops by an order of magnitude from 144Ba to 146Ba, where shell corrections appear to play a significant role. To provide unambiguous insight into the octupole correlations, B(E3) strengths have been measured using Coulomb excitation of 144Ba beams at 650 MeV on a 1 mg/cm2 208Pb target. This experiment represents the first successful measurement utilizing re-accelerated CARIBU beams combined with the γ-ray tracking array GRETINA and the auxiliary charged-particle detector CHICO2. Preliminary results from the experiment will be presented. This work is supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH

  14. A cryogenic test facility

    NASA Astrophysics Data System (ADS)

    Veenendaal, Ian

    The next generation, space-borne instruments for far infrared spectroscopy will utilize large diameter, cryogenically cooled telescopes in order to achieve unprecedented sensitivities. Low background, ground-based cryogenic facilities are required for the cryogenic testing of materials, components and subsystems. The Test Facility Cryostat (TFC) at the University of Lethbridge is a large volume, closed cycle, 4K cryogenic facility, developed for this purpose. This thesis discusses the design and performance of the facility and associated external instrumentation. An apparatus for measuring the thermal properties of materials is presented, and measurements of the thermal expansion and conductivity of carbon fibre reinforced polymers (CFRPs) at cryogenic temperatures are reported. Finally, I discuss the progress towards the design and fabrication of a demonstrator cryogenic, far infrared Fourier transform spectrometer.

  15. Octupole deformation in the ground states of even-even nuclei: A global analysis within the covariant density functional theory

    NASA Astrophysics Data System (ADS)

    Agbemava, S. E.; Afanasjev, A. V.; Ring, P.

    2016-04-01

    A systematic investigation of octupole-deformed nuclei is presented for even-even systems with Z ≤106 located between the two-proton and two-neutron driplines. For this study we use five most-up-to-date covariant energy density functionals of different types, with a nonlinear meson coupling, with density-dependent meson couplings, and with density-dependent zero-range interactions. Pairing correlations are treated within relativistic Hartree-Bogoliubov theory based on an effective separable particle-particle interaction of finite range. This allows us to assess theoretical uncertainties within the present covariant models for the prediction of physical observables relevant for octupole-deformed nuclei. In addition, a detailed comparison with the predictions of nonrelativistic models is performed. A new region of octupole deformation, centered around Z ˜98 ,N ˜196 is predicted for the first time. In terms of its size in the (Z ,N ) plane and the impact of octupole deformation on binding energies this region is similar to the best known region of octupole-deformed nuclei centered at Z ˜90 ,N ˜136 . For the later island of octupole-deformed nuclei, the calculations suggest substantial increase of its size as compared with available experimental data.

  16. High Spin States and Octupole Deformation in Neutron-Rich ^145,147La Nuclei

    NASA Astrophysics Data System (ADS)

    Zhu, S. J.; Hamilton, J. H.; Ramayya, A. V.; Babu, B. R. S.; Jones, E. F.; Kormicki, J.; Daniel, A. V.; Hwang, J. K.; Beyer, C. J.; Wang, M. G.; Long, G. L.; Li, M.; Zhu, L. Y.; Gan, C. Y.; Ma, W. C.; Cole, J. D.; Aryaeinejad, R.; Dardenne, Y. X.; Drigert, M. W.; Rasmussen, J. O.; Asztalos, S.; Lee, I. Y.; Macchiavelli, A. O.; Chu, S. Y.; Gregorich, K. E.; Mohar, M. F.; Stoyer, M. A.; Lougheed, R. W.; Moody, K. J.; Wild, J. F.; Prussin, S. G.

    1998-04-01

    High spin states in neutron-rich odd-Z nuclei ^145,147La have been investigated from the study of prompt γ- rays in spontaneous fission of ^252Cf by using γ-γ- and γ-γ-γ- coincidence techniques. Alternating parity bands are extended up to spins I=(41/2) and I=(43/2) in ^145La and ^147La, respectively. Strong E1 transitions between the negative and positive parity bands give evidence for stable octupole deformation. The new higher spin levels give evidence for rotational enhancement of the stability of the octupole deformation. These collective bands show competition and co-existence between symmetric and asymmetric shapes in ^145La. Band crossing was found around hbarω≈ 0.26 ~0.30 MeV in both nuclei and these backbends are related to the alignment of two i_13/2 neutron from cranked shell model calculations.

  17. High-power ion-cyclotron heating on the levitated octupole

    SciTech Connect

    Dexter, R.N.; Fortgang, C.M.; Prager, S.C.; Sprott, J.C.; Strait, E.J.; Twichell, J.C.

    1982-03-01

    Experiments are underway in the Wisconsin Levitated Toroidal Octupole to create hot, dense plasmas to facilitate the study of ..beta.. limits and related phenomena such as Pfirsch-Schlueter and bootstrap currents. The question of ballooning mode instability limits on ..beta.. = 8 ..pi..nk(T/sub i/+T/sub e/)/B/sup 2/ is of general importance for all toroidal systems, and ICRF heating should permit study of high ..beta.. plasmas with lower collisionality and smaller gyroradii than those of the high ..beta.. gun-injected plasmas currently under study in the Octupole. To these ends we are developing sources capable of delivering 4 MW to the plasma (1.5 MW coupled to the plasma to date, the rest under development).

  18. Fundamentals of Cryogenics

    NASA Technical Reports Server (NTRS)

    Johnson, Wesley; Tomsik, Thomas; Moder, Jeff

    2014-01-01

    Analysis of the extreme conditions that are encountered in cryogenic systems requires the most effort out of analysts and engineers. Due to the costs and complexity associated with the extremely cold temperatures involved, testing is sometimes minimized and extra analysis is often relied upon. This short course is designed as an introduction to cryogenic engineering and analysis, and it is intended to introduce the basic concepts related to cryogenic analysis and testing as well as help the analyst understand the impacts of various requests on a test facility. Discussion will revolve around operational functions often found in cryogenic systems, hardware for both tests and facilities, and what design or modelling tools are available for performing the analysis. Emphasis will be placed on what scenarios to use what hardware or the analysis tools to get the desired results. The class will provide a review of first principles, engineering practices, and those relations directly applicable to this subject including such topics as cryogenic fluids, thermodynamics and heat transfer, material properties at low temperature, insulation, cryogenic equipment, instrumentation, refrigeration, testing of cryogenic systems, cryogenics safety and typical thermal and fluid analysis used by the engineer. The class will provide references for further learning on various topics in cryogenics for those who want to dive deeper into the subject or have encountered specific problems.

  19. Mixed-symmetry octupole and hexadecapole excitations in N=52 isotones

    NASA Astrophysics Data System (ADS)

    Hennig, Andreas; Spieker, Mark; Werner, Volker; Ahn, Tan; Anagnostatou, Vassia; Cooper, Nathan; Derya, Vera; Elvers, Michael; Endres, Janis; Goddard, Phil; Heinz, Andreas; Hughes, Richard O.; Ilie, Gabriela; Mineva, Milena N.; Pickstone, Simon G.; Petkov, Pavel; Pietralla, Norbert; Radeck, Desirée; Ross, Tim J.; Savran, Deniz; Zilges, Andreas

    2015-05-01

    In addition to the well-established quadrupole mixed-symmetry states, octupole and hexadecapole excitations with mixed-symmetry character have been recently proposed for the N = 52 isotones 92Zr and 94Mo. We performed two inelastic proton-scattering experiments to study this kind of excitations in the heaviest stable N = 52 isotone 96Ru. From the combined experimental data of both experiments absolute transition strengths were extracted.

  20. Coherent quadrupole-octupole modes and split parity-doublet spectra in odd-A nuclei

    SciTech Connect

    Minkov, N.; Drenska, S.; Yotov, P.; Lalkovski, S.; Bonatsos, D.; Scheid, W.

    2007-09-15

    A collective model describing coherent quadrupole-octupole oscillations and rotations with a Coriolis coupling between the even-even core and the unpaired nucleon is applied to odd nuclei. The particle-core coupling provides a parity-doublet structure of the spectrum, whereas the quadrupole-octupole motion leads to a splitting of the doublet energy levels. The formalism successfully reproduces the split parity-doublet spectra and the attendant B(E1) and B(E2) transition probabilities in a wide range of odd-A nuclei. It provides estimations for the influence of the Coriolis interaction on the collective motion and subsequently for the value of angular momentum projection K on which the spectrum is built. The analysis of the energy splitting and B(E1) transition probabilities between opposite parity counterparts suggests degenerate doublet structures at high angular momenta. The study provides information about the evolution of quadrupole-octupole collectivity in odd-mass nuclei.

  1. Spectroscopy of quadrupole and octupole states in rare-earth nuclei from a Gogny force

    NASA Astrophysics Data System (ADS)

    Nomura, K.; Rodríguez-Guzmán, R.; Robledo, L. M.

    2015-07-01

    Collective quadrupole and octupole states are described in a series of Sm and Gd isotopes within the framework of the interacting boson model (IBM), whose Hamiltonian parameters are deduced from mean-field calculations with the Gogny energy density functional. The link between both frameworks is the (β2β3 ) potential energy surface computed within the Hartree-Fock-Bogoliubov framework in the case of the Gogny force. The diagonalization of the IBM Hamiltonian provides excitation energies and transition strengths of an assorted set of states including both positive- and negative-parity states. The resultant spectroscopic properties are compared with the available experimental data and also with the results of the configuration mixing calculations with the Gogny force within the generator coordinate method (GCM). The structure of excited 0+ states and its connection with double-octupole phonons is also addressed. The model is shown to describe the empirical trend of the low-energy quadrupole and octupole collective structure fairly well and turns out to be consistent with GCM results obtained with the Gogny force.

  2. Cryogenic actuator for subnanometer positioning

    NASA Astrophysics Data System (ADS)

    Bree, B. v.; Janssen, H.; Paalvast, S.; Albers, R.

    2012-09-01

    This paper discusses the development, realization, and qualification of a positioning actuator concept specifically for cryogenic environments. Originally developed for quantum physics research, the actuator also has many applications in astronomic cryogenic instruments to position optical elements with nanometer level accuracy and stability. Typical applications include the correction of thermally induced position errors of optical components after cooling down from ambient to cryogenic temperatures or sample positioning in microscopes. The actuator is nicknamed the ‘PiezoKnob’ because it is piezo based and it is compatible with the typical manipulator knob often found in standard systems for optical benches, such as linear stages or tip/tilt lens holders. Actuation with high stiffness piezo elements enables the Piezoknob to deliver forces up to 50 Newton which allows relatively stiff guiding mechanisms or large pre-loads. The PiezoKnob has been qualified at 77 Kelvin and was shown to work down to 2 Kelvin. As part of the qualification program, the custom developed driving electronics and set point profile have been fine-tuned, by combing measurements with predictions from a dynamic model, thus maximizing efficiency and minimizing power dissipation. Furthermore, the actuator holds its position without power and thanks to its mechanical layout it is absolutely insensitive to drift of the piezo elements or the driving electronics.

  3. Spacecraft-borne long life cryogenic refrigeration: Status and trends

    NASA Technical Reports Server (NTRS)

    Johnson, A. L.

    1983-01-01

    The status of cryogenic refrigerator development intended for, or possibly applicable to, long life spacecraft-borne application is reviewed. Based on these efforts, the general development trends are identified. Using currently projected technology needs, the various trends are compared and evaluated. The linear drive, non-contacting bearing Stirling cycle refrigerator concept appears to be the best current approach that will meet the technology projection requirements for spacecraft-borne cryogenic refrigerators. However, a multiply redundant set of lightweight, moderate life, moderate reliability Stirling cycle cryogenic refrigerators using high-speed linear drive and sliding contact bearings may possibly suffice.

  4. Octupole correlations in low-lying states of 150Nd and 150Sm and their impact on neutrinoless double-β decay

    NASA Astrophysics Data System (ADS)

    Yao, J. M.; Engel, J.

    2016-07-01

    We present a generator-coordinate calculation, based on a relativistic energy-density functional, of the low-lying spectra in the isotopes 150Nd and 150Sm and of the nuclear matrix element that governs the neutrinoless double-β decay of the first isotope to the second. We carefully examine the impact of octupole correlations on both nuclear structure and the double-β decay matrix element. Octupole correlations turn out to reduce quadrupole collectivity in both nuclei. Shape fluctuations, however, dilute the effects of octupole deformation on the double-β decay matrix element, so that the overall octupole-induced quenching is only about 7 % .

  5. Sealing Mechanical Cryogenic Coolers

    NASA Technical Reports Server (NTRS)

    Richter, R.

    1985-01-01

    Metal bellows used to seal Vuilleumier and Stirling-cycle cryogenic coolers, replacing sliding seals that failed after only 3,000 hours of service. Metal bellows, incorporated in displacer design provide nonrubbing dynamic seal. Lifetime of cryogenic cooler no longer limited by loss of sealing material and by deterioration of regenerators due to clogging by seal debris.

  6. Cryogenic storage devices

    SciTech Connect

    Pelloux-gervais, P.

    1982-02-09

    The present invention relates to a device for the cryogenic storing of products. In a tank, canisters are suspended via rods, and these rods rest on the rim of the tank via retaining heads. The invention is applicable to the cryogenic storage of seeds, semen, vegetable substances, etc.

  7. Cryogenic Information Center

    NASA Technical Reports Server (NTRS)

    Mohling, Robert A.; Marquardt, Eric D.; Fusilier, Fred C.; Fesmire, James E.

    2003-01-01

    The Cryogenic Information Center (CIC) is a not-for-profit corporation dedicated to preserving and distributing cryogenic information to government, industry, and academia. The heart of the CIC is a uniform source of cryogenic data including analyses, design, materials and processes, and test information traceable back to the Cryogenic Data Center of the former National Bureau of Standards. The electronic database is a national treasure containing over 146,000 specific bibliographic citations of cryogenic literature and thermophysical property data dating back to 1829. A new technical/bibliographic inquiry service can perform searches and technical analyses. The Cryogenic Material Properties (CMP) Program consists of computer codes using empirical equations to determine thermophysical material properties with emphasis on the 4-300K range. CMP's objective is to develop a user-friendly standard material property database using the best available data so government and industry can conduct more accurate analyses. The CIC serves to benefit researchers, engineers, and technologists in cryogenics and cryogenic engineering, whether they are new or experienced in the field.

  8. MOSFET's for Cryogenic Amplifiers

    NASA Technical Reports Server (NTRS)

    Dehaye, R.; Ventrice, C. A.

    1987-01-01

    Study seeks ways to build transistors that function effectively at liquid-helium temperatures. Report discusses physics of metaloxide/semiconductor field-effect transistors (MOSFET's) and performances of these devices at cryogenic temperatures. MOSFET's useful in highly sensitive cryogenic preamplifiers for infrared astronomy.

  9. The cryogenic wind tunnel

    NASA Technical Reports Server (NTRS)

    Kilgore, R. A.

    1976-01-01

    Based on theoretical studies and experience with a low speed cryogenic tunnel and with a 1/3-meter transonic cryogenic tunnel, the cryogenic wind tunnel concept was shown to offer many advantages with respect to the attainment of full scale Reynolds number at reasonable levels of dynamic pressure in a ground based facility. The unique modes of operation available in a pressurized cryogenic tunnel make possible for the first time the separation of Mach number, Reynolds number, and aeroelastic effects. By reducing the drive-power requirements to a level where a conventional fan drive system may be used, the cryogenic concept makes possible a tunnel with high productivity and run times sufficiently long to allow for all types of tests at reduced capital costs and, for equal amounts of testing, reduced total energy consumption in comparison with other tunnel concepts.

  10. Cryogenic Pound Circuits for Cryogenic Sapphire Oscillators

    NASA Technical Reports Server (NTRS)

    Dick, G. John; Wang, Rabi

    2006-01-01

    Two modern cryogenic variants of the Pound circuit have been devised to increase the frequency stability of microwave oscillators that include cryogenic sapphire-filled cavity resonators. The original Pound circuit is a microwave frequency discriminator that provides feedback to stabilize a voltage-controlled microwave oscillator with respect to an associated cavity resonator. In the present cryogenic Pound circuits, the active microwave devices are implemented by use of state-of-the-art commercially available tunnel diodes that exhibit low flicker noise (required for high frequency stability) and function well at low temperatures and at frequencies up to several tens of gigahertz. While tunnel diodes are inherently operable as amplitude detectors and amplitude modulators, they cannot, by themselves, induce significant phase modulation. Therefore, each of the present cryogenic Pound circuits includes passive circuitry that transforms the AM into the required PM. Each circuit also contains an AM detector that is used to sample the microwave signal at the input terminal of the high-Q resonator for the purpose of verifying the desired AM null at this point. Finally, each circuit contains a Pound signal detector that puts out a signal, at the modulation frequency, having an amplitude proportional to the frequency error in the input signal. High frequency stability is obtained by processing this output signal into feedback to a voltage-controlled oscillator to continuously correct the frequency error in the input signal.

  11. Cryogenic activities at ESTEC

    NASA Astrophysics Data System (ADS)

    Jewell, C. I.

    1989-05-01

    Although the main present cryogenic activity in ESTEC revolves around the preparation of ISO for launch in 1993, many other activities such as Meteosat second generation, FIRST, GRASP, QUASAT, and X-ray detection using bolometers all require some form of cooling to 80 K or less. ESTEC, in an effort to overcome the major constraint of lifetime when using the solution of cryogens is currently involved in the study and development of two mechanical coolers for work in the temperature ranges of 80 and 4 K are based on a Stirling cycle. This paper gives an overview of ESTEC cryogenic interests with an emphasis on the above mechanical coolers.

  12. FRIB Cryogenic Plant Status

    SciTech Connect

    Dixon, Kelly D.; Ganni, Venkatarao; Knudsen, Peter N.; Casagranda, Fabio

    2015-12-01

    After practical changes were approved to the initial conceptual design of the cryogenic system for MSU FRIB and an agreement was made with JLab in 2012 to lead the design effort of the cryogenic plant, many activities are in place leading toward a cool-down of the linacs prior to 2018. This is mostly due to using similar equipment used at CHLII for the 12 GeV upgrade at JLab and an aggressive schedule maintained by the MSU Conventional Facilities department. Reported here is an updated status of the cryogenic plant, including the equipment procurement status, plant layout, facility equipment and project schedule.

  13. Application of the triaxial quadrupole-octupole rotor to the ground and negative-parity levels of actinide nuclei

    NASA Astrophysics Data System (ADS)

    Nadirbekov, M. S.; Minkov, N.; Strecker, M.; Scheid, W.

    2016-03-01

    In this work, we examine the possibility to describe yrast positive- and negative-parity excitations of deformed even-even nuclei through a collective rotation model in which the nuclear surface is characterized by triaxial quadrupole and octupole deformations. The nuclear moments of inertia are expressed as sums of quadrupole and octupole parts. By assuming an adiabatic separation of rotation and vibration degrees of freedom, we suppose that the structure of the positive- and negative-parity bands may be determined by the triaxial-rigid-rotor motion of the nucleus. By diagonalizing the Hamiltonian in a symmetrized rotor basis with embedded parity, we obtain a model description for the yrast positive- and negative-parity bands in several actinide nuclei. We show that the energy displacement between the opposite-parity sequences can be explained as the result of the quadrupole-octupole triaxiality.

  14. Liquid cryogenic lubricant

    NASA Technical Reports Server (NTRS)

    Dietrich, M. W.; Townsend, D. P.; Zaretsky, E. V.

    1970-01-01

    Fluorinated polyethers are suitable lubricants for rolling-element bearings in cryogenic systems. Lubrication effectiveness is comparable to that of super-refined mineral oil lubricants operating at room temperature.

  15. CRYOGENICS IN BEPCII UPGRADE.

    SciTech Connect

    JIA,L.; WANG,L.; LI,S.

    2002-07-22

    THIS PAPER PRESENTS A CRYOGENIC DESIGN FOR UPGRADING THE BEIJING ELECTRON POSITRON COLLIDER AT THE INSTITUTE OF HIGH ENERGY PHYSICS IN BEIJING. THE UPGRADE INVOLVES 3 NEW SUPERCONDUCTING FACILITIES, THE INTERACTION REGION QUADRUPOLE MAGNETS, THE DETECTOR SOLENOID MAGNETS AND THE SRF CAVITIES. FOR COOLING OF THESE DEVICES, A NEW CRYPLANT WITH A TOTAL CAPACITY OF 1.0KW AT 4.5K IS TO BE BUILT AT IHEP. AN INTEGRATED CRYOGENIC DESIGN TO FIT THE BEPCII CRYOGENIC LOADS WITH HIGH EFFICIENCY IS CARRIEDOUT USING COMPUTATIONAL PROCESS ANALYSIS SOFTWARE WITH THE EMPHASES ON ECONOMICS AND SAFETY IN BOTH CONSTRUCTION AND OPERATION OF THE PLANT. THIS PAPER DESCRIBES THE CRYOGENIC CHARACTERISTICS OF EACH SUPERCONDUCTING DEVICE, THEIR COOLING SCHEMES AND THE OVERALL CRYOPLANT.

  16. Cryogenic Insulation Systems

    NASA Technical Reports Server (NTRS)

    Augustynowicz, S. D.; Fesmire, J. E.; Wikstrom, J. P.

    1999-01-01

    The results of a comparative study of cryogenic insulation systems performed are presented. The key aspects of thermal insulation relative to cryogenic system design, testing, manufacturing, and maintenance are discussed. An overview of insulation development from an energy conservation perspective is given. Conventional insulation materials for cryogenic applications provide three levels of thermal conductivity. Actual thermal performance of standard multilayer insulation (MLI) is several times less than laboratory performance and often 10 times worse than ideal performance. The cost-effectiveness of the insulation system depends on thermal performance; flexibility and durability; ease of use in handling, installation, and maintenance; and overall cost including operations, maintenance, and life cycle. Results of comprehensive testing of both conventional and novel materials such as aerogel composites using cryostat boil-off methods are given. The development of efficient, robust cryogenic insulation systems that operate at a soft vacuum level is the primary focus of this paper.

  17. A novel antiproton radial diagnostic based on octupole induced ballistic loss

    SciTech Connect

    Andresen, G. B.; Bowe, P. D.; Hangst, J. S.; Bertsche, W.; Butler, E.; Charlton, M.; Humphries, A. J.; Jenkins, M. J.; Joergensen, L. V.; Madsen, N.; Werf, D. P. van der; Bray, C. C.; Chapman, S.; Fajans, J.; Povilus, A.; Wurtele, J. S.; Cesar, C. L.; Lambo, R.; Silveira, D. M.; Fujiwara, M. C.

    2008-03-15

    We report results from a novel diagnostic that probes the outer radial profile of trapped antiproton clouds. The diagnostic allows us to determine the profile by monitoring the time history of antiproton losses that occur as an octupole field in the antiproton confinement region is increased. We show several examples of how this diagnostic helps us to understand the radial dynamics of antiprotons in normal and nested Penning-Malmberg traps. Better understanding of these dynamics may aid current attempts to trap antihydrogen atoms.

  18. Cryogenic Feedthrough Test Rig

    NASA Technical Reports Server (NTRS)

    Skaff, Antony

    2009-01-01

    The cryogenic feedthrough test rig (CFTR) allows testing of instrumentation feedthroughs at liquid oxygen and liquid hydrogen temperature and pressure extremes (dangerous process fluid) without actually exposing the feedthrough to a combustible or explosive process fluid. In addition, the helium used (inert gas), with cryogenic heat exchangers, exposes the feedthrough to that environment that allows definitive leak rates of feedthrough by typical industry-standard helium mass spectrometers.

  19. Evidence for hidden quadrupolar fluctuations behind the octupole order in Ce0.7La0.3B6 from resonant x-ray diffraction in magnetic fields

    NASA Astrophysics Data System (ADS)

    Matsumura, Takeshi; Michimura, Shinji; Inami, Toshiya; Otsubo, Toru; Tanida, Hiroshi; Iga, Fumitoshi; Sera, Masafumi

    2014-01-01

    The multipole ordered phase in Ce0.7La0.3B6, emerging below 1.5 K and named phase IV, has been studied by resonant x-ray diffraction in magnetic fields. By utilizing diamond x-ray phase plates to rotate the incident linear polarization and a conventional crystal analyzer system, full linear polarization analysis has been performed to identify the order parameters. The analysis shows that the Γ5g(Oyz, Ozx, Oxy) quadrupoles are more induced by the field than the Γ3g (O20 and O22) quadrupoles on the Γ5u (Tx+y +zβ) antiferro-octupole order in phase IV. The problem is that this result is contradictory to a mean-field calculation, which inevitably gives the Γ3g quadrupole as the main induced moment. This result indicates that the Γ5g quadrupole order is close in energy. We consider that a large fluctuation of the Γ5g quadrupole is hidden behind the primary ordering of the Γ5u octupole and that the multipolar fluctuation significantly affects the ordering phenomenon.

  20. Spacecraft cryogenic gas storage systems

    NASA Technical Reports Server (NTRS)

    Rysavy, G.

    1971-01-01

    Cryogenic gas storage systems were developed for the liquid storage of oxygen, hydrogen, nitrogen, and helium. Cryogenic storage is attractive because of the high liquid density and low storage pressure of cryogens. This situation results in smaller container sizes, reduced container-strength levels, and lower tankage weights. The Gemini and Apollo spacecraft used cryogenic gas storage systems as standard spacecraft equipment. In addition to the Gemini and Apollo cryogenic gas storage systems, other systems were developed and tested in the course of advancing the state of the art. All of the cryogenic storage systems used, developed, and tested to date for manned-spacecraft applications are described.

  1. High-accuracy optical clock based on the octupole transition in 171Yb+.

    PubMed

    Huntemann, N; Okhapkin, M; Lipphardt, B; Weyers, S; Tamm, Chr; Peik, E

    2012-03-01

    We experimentally investigate an optical frequency standard based on the 467 nm (642 THz) electric-octupole reference transition (2)S(1/2)(F=0)→(2)F(7/2)(F=3) in a single trapped (171)Yb(+) ion. The extraordinary features of this transition result from the long natural lifetime and from the 4f(13)6s(2) configuration of the upper state. The electric-quadrupole moment of the (2)F(7/2) state is measured as -0.041(5)ea(0)(2), where e is the elementary charge and a(0) the Bohr radius. We also obtain information on the differential scalar and tensorial components of the static polarizability and of the probe-light-induced ac Stark shift of the octupole transition. With a real-time extrapolation scheme that eliminates this shift, the unperturbed transition frequency is realized with a fractional uncertainty of 7.1×10(-17). The frequency is measured as 642 121 496 772 645.15(52) Hz. PMID:22463621

  2. High-Accuracy Optical Clock Based on the Octupole Transition in Yb+171

    NASA Astrophysics Data System (ADS)

    Huntemann, N.; Okhapkin, M.; Lipphardt, B.; Weyers, S.; Tamm, Chr.; Peik, E.

    2012-03-01

    We experimentally investigate an optical frequency standard based on the 467 nm (642 THz) electric-octupole reference transition S1/22(F=0)→F7/22(F=3) in a single trapped Yb+171 ion. The extraordinary features of this transition result from the long natural lifetime and from the 4f136s2 configuration of the upper state. The electric-quadrupole moment of the F7/22 state is measured as -0.041(5)ea02, where e is the elementary charge and a0 the Bohr radius. We also obtain information on the differential scalar and tensorial components of the static polarizability and of the probe-light-induced ac Stark shift of the octupole transition. With a real-time extrapolation scheme that eliminates this shift, the unperturbed transition frequency is realized with a fractional uncertainty of 7.1×10-17. The frequency is measured as 642 121 496 772 645.15(52) Hz.

  3. Non-Axial Octupole Deformations and Tetrahedral Symmetry in Heavy Nuclei

    SciTech Connect

    Mazurek, Katarzyna; Dudek, Jerzy

    2005-11-21

    The total energies of about 120 nuclei in the Thorium region have been calculated within the macroscopic-microscopic method in the 5-dimensional space of deformation parameters {alpha}20, {alpha}22, {alpha}30, {alpha}32 and {alpha}40. The macroscopic energy term contains the nuclear surface-curvature dependence as proposed within the LSD approach. The microscopic energies are calculated with the Woods-Saxon single particle potential employing the universal set of parameters.We study a possible presence of the octupole axial and non-axial degrees of freedom all-over in the ({beta}, {gamma})-plane focussing on the ground-states, secondary minima and in the saddle points. In fact, a competition between axial and tri-axial octupole deformation parameters is obtained at the saddle points and in the secondary minima for many isotones with N > 136. The presence of the tetrahedral symmetry minima is predicted in numerous nuclei in the discussed region, although most of the time at relatively high excitation energies.

  4. Hyperfine-induced electric dipole contributions to the electric octupole and magnetic quadrupole atomic clock transitions

    NASA Astrophysics Data System (ADS)

    Dzuba, V. A.; Flambaum, V. V.

    2016-05-01

    Hyperfine-induced electric dipole contributions may significantly increase probabilities of otherwise very weak electric octupole and magnetic quadrupole atomic clock transitions (e.g., transitions between s and f electron orbitals). These transitions can be used for exceptionally accurate atomic clocks, quantum information processing, and the search for dark matter. They are very sensitive to new physics beyond the standard model, such as temporal variation of the fine-structure constant, the Lorentz invariance, and Einstein equivalence principle violation. We formulate conditions under which the hyperfine-induced electric dipole contribution dominates and perform calculations of the hyperfine structure and E3, M2 and the hyperfine-induced E1 transition rates for a large number of atoms and ions of experimental interest. Due to the hyperfine quenching the electric octupole clock transition in +173Yb is 2 orders of magnitude stronger than that in currently used +171Yb. Some enhancement is found in 13+143Nd, 14+149Pm, 14+147Sm, and 15+147Sm ions.

  5. Construction and Operational Experience with a Superconducting Octupole Used to Trap Antihydrogen

    SciTech Connect

    Wanderer P.; Escallier, J.; Marone, A.; Parker, B.

    2011-09-06

    A superconducting octupole magnet has seen extensive service as part of the ALPHA experiment at CERN. ALPHA has trapped antihydrogen, a crucial step towards performing precision measurements of anti-atoms. The octupole was made at the Direct Wind facility by the Superconducting Magnet Division at Brookhaven National Laboratory. The magnet was wound with a six-around-one NbTi cable about 1 mm in diameter. It is about 300 mm long, with a radius of 25 mm and a peak field at the conductor of 4.04 T. Specific features of the magnet, including a minimal amount of material in the coil and coil ends with low multipole content, were advantageous to its use in ALPHA. The magnet was operated for six months a year for five years. During this time it underwent about 900 thermal cycles (between 4K and 100K). A novel operational feature is that during the course of data-taking the magnet was repeatedly shut off from its 950 A operating current. The magnet quenches during the shutoff, with a decay constant of 9 ms. Over the course of the five years, the magnet was deliberately quenched many thousands of times. It still performs well.

  6. TPC magnet cryogenic system

    SciTech Connect

    Green, M.A.; Burns, W.A.; Taylor, J.D.; Van Slyke, H.W.

    1980-03-01

    The Time Projection Chamber (TPC) magnet at LBL and its compensation solenoids are adiabatically stable superconducting solenoid magnets. The cryogenic system developed for the TPC magnet is discussed. This system uses forced two-phase tubular cooling with the two cryogens in the system. The liquid helium and liquid nitrogen are delivered through the cooled load by forced tubular flow. The only reservoirs of liquid cryogen exist in the control dewar (for liquid helium) and the conditioner dewar (for liquid nitrogen). The operation o these systems during virtually all phases of system operation are described. Photographs and diagrams of various system components are shown, and cryogenic system data are presented in the following sections: (1) heat leaks into the TPC coil package and the compensation solenoids; (2) heat leaks to various components of the TPC magnet cryogenics system besides the magnets and control dewar; (3) the control dewar and its relationship to the rest of the system; (4) the conditioner system and its role in cooling down the TPC magnet; (5) gas-cooled electrical leads and charging losses; and (6) a summation of the liquid helium and liquid nitrogen requirements for the TPC superconducting magnet system.

  7. One-phonon octupole vibrational states in 211At, 212Rn, 213Fr and 214Ra with N = 126

    NASA Astrophysics Data System (ADS)

    Hwang, J. K.; Hamilton, J. H.; Ramayya, A. V.

    2013-12-01

    Excited high spin states in 211At, 212Rn, 213Fr and 214Ra with N = 126 are reorganized and interpreted in terms of the stretched weak coupling of an octupole 3- phonon. Nearly identical sequences of levels with ΔI = 3 and the parity change are found, for the first time, up to 25- for 20 states of 214Ra, up to 35- for 36 states of 212Rn and up to 53/2+ for 16 states of 213Fr. The stretched weak coupling of an octupole phonon is extended up to the highest excitation energy of 11355 keV for 212Rn which has the largest experimental B( E3) value of 44.1(88) W.u. for the 11- → 8{2/+} transition. The stretched weak coupling of an octupole 3- phonon needs to be considered when single particle configurations are assigned to high spin states. Average octupole excitation energies of 657(51) keV for 211At, 1101(28) keV for 212Rn, 667(25) keV for 213Fr, and 709(25) keV for 214Ra are obtained. The calculated level enegies are in a good agreement with the experimental level energies within the error limit of 4.3%.

  8. Cryogenic process simulation

    SciTech Connect

    Panek, J.; Johnson, S.

    1994-01-01

    Combining accurate fluid property databases with a commercial equation-solving software package running on a desktop computer allows simulation of cryogenic processes without extensive computer programming. Computer simulation can be a powerful tool for process development or optimization. Most engineering simulations to date have required extensive programming skills in languages such as Fortran, Pascal, etc. Authors of simulation code have also usually been responsible for choosing and writing the particular solution algorithm. This paper describes a method of simulating cryogenic processes with a commercial software package on a desktop personal computer that does not require these traditional programming tasks. Applications include modeling of cryogenic refrigerators, heat exchangers, vapor-cooled power leads, vapor pressure thermometers, and various other engineering problems.

  9. Cryogenic wind tunnels. II

    NASA Technical Reports Server (NTRS)

    Kilgore, Robert A.

    1987-01-01

    The application of the cryogenic concept to various types of tunnels including Ludwieg tube tunnel, Evans clean tunnel, blowdown, induced-flow, and continuous-flow fan-driven tunnels is discussed. Benefits related to construction and operating costs are covered, along with benefits related to new testing capabilities. It is noted that cooling the test gas to very low temperatures increases Reynolds number by more than a factor of seven. From the energy standpoint, ambient-temperature fan-driven closed-return tunnels are considered to be the most efficient type of tunnel, while a large reduction in the required tunnel stagnation pressure can be achieved through cryogenic operation. Operating envelopes for three modes of operation for a cryogenic transonic pressure tunnel with a 2.5 by 2.5 test section are outlined. A computer program for calculating flow parameters and power requirements for wind tunnels with operating temperatures from saturation to above ambient is highlighted.

  10. ESS Cryogenic System Process Design

    NASA Astrophysics Data System (ADS)

    Arnold, P.; Hees, W.; Jurns, J.; Su, X. T.; Wang, X. L.; Weisend, J. G., II

    2015-12-01

    The European Spallation Source (ESS) is a neutron-scattering facility funded and supported in collaboration with 17 European countries in Lund, Sweden. Cryogenic cooling at ESS is vital particularly for the linear accelerator, the hydrogen target moderators, a test stand for cryomodules, the neutron instruments and their sample environments. The paper will focus on specific process design criteria, design decisions and their motivations for the helium cryoplants and auxiliary equipment. Key issues for all plants and their process concepts are energy efficiency, reliability, smooth turn-down behaviour and flexibility. The accelerator cryoplant (ACCP) and the target moderator cryoplant (TMCP) in particular need to be prepared for a range of refrigeration capacities due to the intrinsic uncertainties regarding heat load definitions. Furthermore the paper addresses questions regarding process arrangement, 2 K cooling methodology, LN2 precooling, helium storage, helium purification and heat recovery.

  11. Ball Aerospace Actuator Cryogenic Testing

    NASA Technical Reports Server (NTRS)

    Kingsbury, Lana; Lightsey, Paul; Quigley, Phil; Rutkowski, Joel; Russell, J. Kevin (Technical Monitor)

    2002-01-01

    The ambient testing characterizing step size and repeatability for the Ball Aerospace Cryogenic Nano-Positioner actuators for the AMSD (Advanced Mirror System Demonstrator) program has been completed and are presented. Current cryogenic testing is underway. Earlier cryogenic test results for a pre-cursor engineering model are presented.

  12. Cryogenic Hybrid Magnetic Bearing

    NASA Technical Reports Server (NTRS)

    Meeks, Crawford R.; Dirusso, Eliseo; Brown, Gerald V.

    1994-01-01

    Cryogenic hybrid magnetic bearing is example of class of magnetic bearings in which permanent magnets and electromagnets used to suspend shafts. Electromagnets provide active control of position of shaft. Bearing operates at temperatures from -320 degrees F (-196 degrees C) to 650 degrees F (343 degrees C); designed for possible use in rocket-engine turbopumps, where effects of cryogenic environment and fluid severely limit lubrication of conventional ball bearings. This and similar bearings also suitable for terrestrial rotating machinery; for example, gas-turbine engines, high-vacuum pumps, canned pumps, precise gimbals that suspend sensors, and pumps that handle corrosive or gritty fluids.

  13. Cryogenic Model Materials

    NASA Technical Reports Server (NTRS)

    Kimmel, W. M.; Kuhn, N. S.; Berry, R. F.; Newman, J. A.

    2001-01-01

    An overview and status of current activities seeking alternatives to 200 grade 18Ni Steel CVM alloy for cryogenic wind tunnel models is presented. Specific improvements in material selection have been researched including availability, strength, fracture toughness and potential for use in transonic wind tunnel testing. Potential benefits from utilizing damage tolerant life-prediction methods, recently developed fatigue crack growth codes and upgraded NDE methods are also investigated. Two candidate alloys are identified and accepted for cryogenic/transonic wind tunnel models and hardware.

  14. Unique Cryogenic Welded Structures

    NASA Astrophysics Data System (ADS)

    Yushchenko, K. A.; Monko, G. G.

    2004-06-01

    For the last few decades, the E. O. Paton Electric Welding Institute has been active in the field of cryogenic materials science. Integrated research on development of new grades of steels and alloys for cryogenic engineering was carried out in collaboration with the leading institutions of Russia, Ukraine, and Georgia. Commercially applied welding technologies and consumables were developed. They include large, spherical tanks for storage of liquefied gases (from oxygen to helium) under high pressures; space simulators with a capacity of 10 000 m3 and more; and load-carrying elements of superconducting fusion magnetic systems for the TOKAMAK, MGD, and ITER series.

  15. Unique Cryogenic Welded Structures

    SciTech Connect

    Yushchenko, K.A.; Monko, G.G.

    2004-06-28

    For the last few decades, the E. O. Paton Electric Welding Institute has been active in the field of cryogenic materials science. Integrated research on development of new grades of steels and alloys for cryogenic engineering was carried out in collaboration with the leading institutions of Russia, Ukraine, and Georgia. Commercially applied welding technologies and consumables were developed. They include large, spherical tanks for storage of liquefied gases (from oxygen to helium) under high pressures; space simulators with a capacity of 10 000 m3 and more; and load-carrying elements of superconducting fusion magnetic systems for the TOKAMAK, MGD, and ITER series.

  16. Cryogenic Propellant Densification Study

    NASA Technical Reports Server (NTRS)

    Ewart, R. O.; Dergance, R. H.

    1978-01-01

    Ground and vehicle system requirements are evaluated for the use of densified cryogenic propellants in advanced space transportation systems. Propellants studied were slush and triple point liquid hydrogen, triple point liquid oxygen, and slush and triple point liquid methane. Areas of study included propellant production, storage, transfer, vehicle loading and system requirements definition. A savings of approximately 8.2 x 100,000 Kg can be achieved in single stage to orbit gross liftoff weight for a payload of 29,484 Kg by utilizing densified cryogens in place of normal boiling point propellants.

  17. Computed tomography of cryogenic cells

    SciTech Connect

    Schneider, Gerd; Anderson, E.; Vogt, S.; Knochel, C.; Weiss, D.; LeGros, M.; Larabell, C.

    2001-08-30

    Due to the short wavelengths of X-rays and low numerical aperture of the Fresnel zone plates used as X-ray objectives, the depth of field is several microns. Within the focal depth, imaging a thick specimen is to a good approximation equivalent to projecting the specimen absorption. Therefore, computed tomography based on a tilt series of X-ray microscopic images can be used to reconstruct the local linear absorption coefficient and image the three-dimensional specimen structure. To preserve the structural integrity of biological objects during image acquisition, microscopy is performed at cryogenic temperatures. Tomography based on X-ray microscopic images was applied to study the distribution of male specific lethal 1 (MSL-1), a nuclear protein involved in dosage compensation in Drosophila melanogaster, which ensures that males with single X chromosome have the same amount of most X-linked gene products as females with two X chromosomes. Tomographic reconstructions of X-ray microscopic images were used to compute the local three-dimensional linear absorption coefficient revealing the arrangement of internal structures of Drosophila melanogaster cells. Combined with labelling techniques, nanotomography is a new technique to study the 3D distribution of selected proteins inside whole cells. We want to improve this technique with respect to resolution and specimen preparation. The resolution in the reconstruction can be significantly improved by reducing the angular step size to collect more viewing angles, which requires an automated data acquisition. In addition, fast-freezing with liquid ethane instead of cryogenic He gas will be applied to improve the vitrification of the hydrated samples. We also plan to apply cryo X-ray nanotomography in order to study different types of cells and their nuclear protein distributions.

  18. Cryogenics Research and Engineering Experience

    NASA Technical Reports Server (NTRS)

    Toro Medina, Jaime A.

    2013-01-01

    Energy efficient storage, transfer and use of cryogens and cryogenic propellants on Earth and in space have a direct impact on NASA, government and commercial programs. Research and development on thermal insulation, propellant servicing, cryogenic components, material properties and sensing technologies provides industry, government and research institutions with the cross-cutting technologies to manage low-temperature applications. Under the direction of the Cryogenic Testing Lab at Kennedy Space Center, the work experience acquired allowed me to perform research, testing, design and analysis of current and future cryogenic technologies to be applied in several projects.

  19. Valve for cryogenic service

    DOEpatents

    Worwetz, H.A.

    1975-09-02

    This patent relates to a valve for use with a liquefied gas at cryogenic temperatures in which a pair of joined knife edges are bellows controlled to contact an indium alloy seat in an annular slot when flow is to be stopped. The sealing alloy may be renewed by heating in situ. (auth)

  20. Compact cryogenic inductors

    SciTech Connect

    Singh, S.K.; Carr, W.J. Jr.; Fagan, T.J. Jr.; Hordubay, T.D.; Chuboy, H.L. . Science and Technology Center)

    1994-07-01

    Power systems requiring power levels as high as a few megawatts to a few gigawatts for periods of several microseconds to several milliseconds with repetitive frequencies of a few hertz to a few kilohertz are being considered for potential space applications. The impulsive nature of the power presents the opportunity to use inductive energy storage techniques for pulse duty to enhance economic and practical considerations. An inductors must be efficient, lightweight, and reliable, and it must have high energy density if it is to be used in space based power systems. Cryogenic inductors are best studied for such an application. Parametric analyses of the two potential types of cryogenic inductors (superconducting and hyperconducting reveal that the hyperconducting (high purity aluminum)) inductor would be significantly lighter and achieve higher energy densities without the added penalty of a helium refrigeration system, thus resulting in improved overall system reliability. The lightweight hyperconducting cryogenic inductor technology is, however, in its infancy. This paper describes the required technology base which would allow the eventual application of the lightweight cryogenic inductor in space power systems, and also conclusively demonstrates the underlying principles.

  1. High Power Cryogenic Targets

    SciTech Connect

    Gregory Smith

    2011-08-01

    The development of high power cryogenic targets for use in parity violating electron scattering has been a crucial ingredient in the success of those experiments. As we chase the precision frontier, the demands and requirements for these targets have grown accordingly. We discuss the state of the art, and describe recent developments and strategies in the design of the next generation of these targets.

  2. High-spin octupole yrast levels in {sup 216}Rn{sub 86}

    SciTech Connect

    Debray, M.E.; Davidson, J.; Davidson, M.; Kreiner, A. J.; Cardona, M. A.; Hojman, D.; Napoli, D.R.; De Angelis, G.; De Poli, M.; Gadea, A.; Lenzi, S.; Bazzacco, D.; Lunardi, S.; Rossi-Alvarez, C.; Ur, C.A.; Medina, N.

    2006-02-15

    The yrast level structure of {sup 216}Rn has been studied using in-beam spectroscopy {alpha}-{gamma}-{gamma} coincidence techniques through the {sup 208}Pb({sup 18}O, 2{alpha}2n) reaction in the 91-93 MeV energy range, using the 8{pi} GASP-ISIS spectrometer at Legnaro. The level scheme of {sup 216}Rn resulting from this study shows alternating parity bands only above a certain excitation energy. From this result, the lightest nucleus showing evidence of octupole collectivity at low spins is still {sup 216}Fr, thereby defining the lowest-mass corner for this kind of phenomenon as N{>=}129 and Z{>=}87.

  3. Test of the transport properties of a helical electrostatic quadrupole and quasi-octupole

    SciTech Connect

    Xiu, L.; Ohnuma, Shoroku; Wang, K. . Dept. of Physics); Meitzler, C.R.; Xu, Y. . Dept. of Physics)

    1993-01-01

    A third-generation continuous helical electrostatic quadrupole (HESQ) lens has been built and tested. The new HESQ is 21.5 cm long and has a 3.6 cm diameter aperture. The HESQ has been tested under two separate conditions: with a pulsed 25 keV, 0.5 mA proton beam; and a 25 keV, 10 mA proton beam. The input emittance was fixed using a multi-aperture collimator. A comparison is made between experiment and numerical simulations for a wide variety of operating conditions. A second possible operating mode is the quasi-octupole mode, which offers significantly reduced aberration when compared to the quadrupole mode. The results of preliminary tests in this operating mode will be presented.

  4. Test of the transport properties of a helical electrostatic quadrupole and quasi-octupole

    SciTech Connect

    Xiu, L.; Ohnuma, Shoroku; Wang, K.; Meitzler, C.R.; Xu, Y.

    1993-06-01

    A third-generation continuous helical electrostatic quadrupole (HESQ) lens has been built and tested. The new HESQ is 21.5 cm long and has a 3.6 cm diameter aperture. The HESQ has been tested under two separate conditions: with a pulsed 25 keV, 0.5 mA proton beam; and a 25 keV, 10 mA proton beam. The input emittance was fixed using a multi-aperture collimator. A comparison is made between experiment and numerical simulations for a wide variety of operating conditions. A second possible operating mode is the quasi-octupole mode, which offers significantly reduced aberration when compared to the quadrupole mode. The results of preliminary tests in this operating mode will be presented.

  5. Rotation induced octupole correlations in the neutron-deficient 109Te nucleus

    NASA Astrophysics Data System (ADS)

    de Angelis, G.; Fahlander, C.; Gadea, A.; Farnea, E.; Bazzacco, D.; Belcari, N.; Blasi, N.; Bizzeti, P. G.; Bizzeti-Sona, A.; de Acuña, D.; de Poli, M.; Grawe, H.; Johnson, A.; Lo Bianco, G.; Lunardi, S.; Napoli, D. R.; Nyberg, J.; Pavan, P.; Persson, J.; Rossi Alvarez, C.; Rudolph, D.; Schubart, R.; Spolaore, P.; Wyss, R.; Xu, F.

    1998-10-01

    High spin states in the neutron deficient nucleus 109Te have been populated with the 58Ni+54Fe reaction at 220 MeV and investigated through γ-spectroscopy methods at the GASP spectrometer making use of reaction channel selection with the ISIS Si-ball. The level scheme has been extended up to an excitation energy of ~12.1 MeV. The spins and parities of the observed levels are assigned tentatively supporting the identification of two bands of opposite parity connected by strong dipole transitions inferred to be of E1 character. Octupole correlations in 109Te induced by rotation are suggested as the cause of this effect.

  6. First Atomic Electric Dipole Moment Limit Derived from an Octupole-Deformed Nucleus

    NASA Astrophysics Data System (ADS)

    Parker, Richard; Bishof, Michael; Kalita, Mukut; Lemke, Nathan; Dietrich, Matt; Bailey, Kevin; Greene, John; Holt, Roy; Korsch, Wolfgang; Lu, Zheng-Tian; Mueller, Peter; O'Connor, T. P.; Singh, Jaideep

    2015-05-01

    Ra-225 (half-life = 15 d, nuclear spin = 1/2) is a promising isotope for a measurement of the EDM of a diamagnetic atom. Due to its large nuclear octupole deformation and high atomic mass, the EDM sensitivity of Ra-225 is expected to be 2-3 orders of magnitude larger than that of Hg-199. We demonstrate an efficient multiple-stage apparatus in which radium atoms are first loaded into a MOT, then transferred into a movable optical-dipole trap (ODT) that carries the atoms over 1 m to a magnetically-shielded science chamber, loaded into a standing-wave ODT, polarized, and then allowed to precess in magnetic and electric fields. We will discuss our first measurement of the EDM of Ra-225, as well as plans for future improvements. This work is supported by DOE, Office of Nuclear Physics (DE-AC02-06CH11357).

  7. Interplay between octupole and quasiparticle excitations in {sup 178}Hg and {sup 180}Hg

    SciTech Connect

    Kondev, F. G.; Janssens, R. V. F.; Carpenter, M. P.; Abu Saleem, K.; Ahmad, I.; Alcorta, M.; Amro, H.; Bhattacharyya, P.; Brown, L. T.; Caggiano, J.

    2000-10-01

    Excited structures in the Z=80, {sup 178}Hg (N=98), and {sup 180}Hg (N=100) isotopes have been investigated with the Gammasphere spectrometer in conjunction with the recoil-decay tagging technique. The present data extend the previously known ground-state bands to higher spin and excitation energy. Negative parity bands with a complex decay towards the low spin states arising from both the prolate-deformed and the nearly spherical coexisting minima have been observed for the first time in both nuclei. It is shown that these sequences have characteristics in common with negative-parity bands in the heavier even-even Hg isotopes as well as in the Os and Pt isotones. These structures are interpreted as being associated at low spin with an octupole vibration which is crossed at moderate frequency by a shape driving, two-quasiproton excitation.

  8. Materials and construction techniques for cryogenic wind tunnel facilities for instruction/research use

    NASA Technical Reports Server (NTRS)

    Morse, S. F.; Roper, A. T.

    1975-01-01

    The results of the cryogenic wind tunnel program conducted at NASA Langley Research Center are presented to provide a starting point for the design of an instructional/research wind tunnel facility. The advantages of the cryogenic concept are discussed, and operating envelopes for a representative facility are presented to indicate the range and mode of operation. Special attention is given to the design, construction and materials problems peculiar to cryogenic wind tunnels. The control system for operation of a cryogenic tunnel is considered, and a portion of a linearized mathematical model is developed for determining the tunnel dynamic characteristics.

  9. Cryogenic thermal diodes

    NASA Astrophysics Data System (ADS)

    Paulsen, Brandon R.; Batty, J. C.; Agren, John

    2000-01-01

    Space based cryogenic thermal management systems for advanced infrared sensor platforms are a critical failure mode to the spacecraft missions they are supporting. Recent advances in cryocooler technologies have increased the achievable cooling capacities and decreased the operating temperatures of these systems, but there is still a fundamental need for redundancy in these systems. Cryogenic thermal diodes act as thermal switches, allowing heat to flow through them when in a conduction mode and restricting the flow of heat when in an isolation mode. These diodes will allow multiple cryocoolers to cool a single infrared focal plane array. The Space Dynamics Laboratory has undertaken an internal research and development effort to develop this innovative technology. This paper briefly describes the design parameters of several prototype thermal diodes that were developed and tested. .

  10. Cryogenic mirror analysis

    NASA Technical Reports Server (NTRS)

    Nagy, S.

    1988-01-01

    Due to extraordinary distances scanned by modern telescopes, optical surfaces in such telescopes must be manufactured to unimaginable standards of perfection of a few thousandths of a centimeter. The detection of imperfections of less than 1/20 of a wavelength of light, for application in the building of the mirror for the Space Infrared Telescope Facility, was undertaken. Because the mirror must be kept very cold while in space, another factor comes into effect: cryogenics. The process to test a specific morror under cryogenic conditions is described; including the follow-up analysis accomplished through computer work. To better illustrate the process and analysis, a Pyrex Hex-Core mirror is followed through the process from the laser interferometry in the lab, to computer analysis via a computer program called FRINGE. This analysis via FRINGE is detailed.

  11. Oxygen chemisorption cryogenic refrigerator

    NASA Technical Reports Server (NTRS)

    Jones, Jack A. (Inventor)

    1987-01-01

    The present invention relates to a chemisorption compressor cryogenic refrigerator which employs oxygen to provide cooling at 60 to 100 K. The invention includes dual vessels containing an oxygen absorbent material, alternately heated and cooled to provide a continuous flow of high pressure oxygen, multiple heat exchangers for precooling the oxygen, a Joule-Thomson expansion valve system for expanding the oxygen to partially liquefy it and a liquid oxygen pressure vessel. The primary novelty is that, while it was believed that once oxygen combined with an element or compound the reaction could not reverse to release gaseous oxygen, in this case oxygen will indeed react in a reversible fashion with certain materials and will do so at temperatures and pressures which make it practical for incorporation into a cryogenic refrigeration system.

  12. Flexible cryogenic conduit

    DOEpatents

    Brindza, Paul Daniel; Wines, Robin Renee; Takacs, James Joseph

    1999-01-01

    A flexible and relatively low cost cryogenic conduit is described. The flexible cryogenic conduit of the present invention comprises a first inner corrugated tube with single braided serving, a second outer corrugated tube with single braided serving concentric with the inner corrugated tube, and arranged outwardly about the periphery of the inner corrugated tube and between the inner and outer corrugated tubes: a superinsulation layer; a one half lap layer of polyester ribbon; a one half lap layer of copper ribbon; a spirally wound refrigeration tube; a second one half lap layer of copper ribbon; a second one half lap layer of polyester ribbon; a second superinsulation layer; a third one half lap layer of polyester ribbon; and a spirally wound stretchable and compressible filament.

  13. Cryogenic support system

    DOEpatents

    Nicol, T.H.; Niemann, R.C.; Gonczy, J.D.

    1988-11-01

    A support system is disclosed for restraining large masses at very low or cryogenic temperatures. The support system employs a tie bar that is pivotally connected at opposite ends to an anchoring support member and a sliding support member. The tie bar extends substantially parallel to the longitudinal axis of the cold mass assembly, and comprises a rod that lengthens when cooled and a pair of end attachments that contract when cooled. The rod and end attachments are sized so that when the tie bar is cooled to cryogenic temperature, the net change in tie bar length is approximately zero. Longitudinal force directed against the cold mass assembly is distributed by the tie bar between the anchoring support member and the sliding support member. 7 figs.

  14. Cryogenic support system

    DOEpatents

    Nicol, Thomas H.; Niemann, Ralph C.; Gonczy, John D.

    1988-01-01

    A support system is disclosed for restraining large masses at very low or cryogenic temperatures. The support system employs a tie bar that is pivotally connected at opposite ends to an anchoring support member and a sliding support member. The tie bar extends substantially parallel to the longitudinal axis of the cold mass assembly, and comprises a rod that lengthens when cooled and a pair of end attachments that contract when cooled. The rod and end attachments are sized so that when the tie bar is cooled to cryogenic temperature, the net change in tie bar length is approximately zero. Longitudinal force directed against the cold mass assembly is distributed by the tie bar between the anchoring support member and the sliding support member.

  15. Cryogenic treatment of gas

    DOEpatents

    Bravo, Jose Luis; Harvey, III, Albert Destrehan; Vinegar, Harold J.

    2012-04-03

    Systems and methods of treating a gas stream are described. A method of treating a gas stream includes cryogenically separating a first gas stream to form a second gas stream and a third stream. The third stream is cryogenically contacted with a carbon dioxide stream to form a fourth and fifth stream. A majority of the second gas stream includes methane and/or molecular hydrogen. A majority of the third stream includes one or more carbon oxides, hydrocarbons having a carbon number of at least 2, one or more sulfur compounds, or mixtures thereof. A majority of the fourth stream includes one or more of the carbon oxides and hydrocarbons having a carbon number of at least 2. A majority of the fifth stream includes hydrocarbons having a carbon number of at least 3 and one or more of the sulfur compounds.

  16. Flexible cryogenic conduit

    SciTech Connect

    Brindza, P.D.; Wines, R.R.; Takacs, J.J.

    1999-12-21

    A flexible and relatively low cost cryogenic conduit is described. The flexible cryogenic conduit of the present invention comprises a first inner corrugated tube with single braided serving, a second outer corrugated tube with single braided serving concentric with the inner corrugated tube, and arranged outwardly about the periphery of the inner corrugated tube and between the inner and outer corrugated tubes: a superinsulation layer; a one half lap layer of polyester ribbon; a one half lap layer of copper ribbon; a spirally wound refrigeration tube; a second one half lap layer of copper ribbon; a second one half lap layer of polyester ribbon; a second superinsulation layer; a third one half lap layer of polyester ribbon; and a spirally wound stretchable and compressible filament.

  17. The Cryogenic Grating Spectrometer

    NASA Technical Reports Server (NTRS)

    Erickson, Edwin F.; Haas, Michael R.; Colgan, Sean W. J.; Simpson, Janet P.; Rubin, Robert H.

    1995-01-01

    The Cryogenic Grating Spectrometer (CGS) first flew on the KAO in 1982 December and has been open to guest investigators since 1984 October. In the past 12 years it has completed over 100 research flights supporting 13 different principal investigators studying a variety of objects. We briefly describe the instrument, its capabilities and accomplishments, and acknowledge the people who have contributed to its development and operation.

  18. Cryogenic Selective Surfaces

    NASA Technical Reports Server (NTRS)

    Youngquist, Robert; Nurge, Mark

    2015-01-01

    Under our NASA Innovative Advanced Concepts (NIAC) project we have theoretically demonstrated a novel selective surface that reflects roughly 100 times more solar radiation than any other known coating. If this prediction holds up under experimental tests it will allow cryogenic temperatures to be reached in deep space even in the presence of the sun. It may allow LOX to be carried to the Moon and Mars. It may allow superconductors to be used in deep space without a refrigeration system.

  19. Cryogenic turbopump bearing materials

    NASA Technical Reports Server (NTRS)

    Bhat, Biliyar N.

    1989-01-01

    Materials used for modern cryogenic turbopump bearings must withstand extreme conditions of loads and speeds under marginal lubrication. Naturally, these extreme conditions tend to limit the bearing life. It is possible to significantly improve the life of these bearings, however, by improving the fatigue and wear resistance of bearing alloys, and improving the strength, liquid oxygen compatibility and lubricating ability of the bearing cage materials. Improved cooling will also help to keep the bearing temperatures low and hence prolong the bearing life.

  20. A compact cryogenic pump

    NASA Astrophysics Data System (ADS)

    Li, Gang; Caldwell, Shane; Clark, Jason A.; Gulick, Sidney; Hecht, Adam; Lascar, Daniel D.; Levand, Tony; Morgan, Graeme; Orford, Rodney; Savard, Guy; Sharma, Kumar S.; Van Schelt, Jonathon

    2016-04-01

    A centrifugal cryogenic pump has been designed at Argonne National Laboratory to circulate liquid nitrogen (LN2) in a closed circuit allowing the recovery of excess fluid. The pump can circulate LN2 at rates of 2-10 L/min, into a head of 0.5-3 m. Over four years of laboratory use the pump has proven capable of operating continuously for 50-100 days without maintenance.

  1. Linear magnetic bearing

    NASA Technical Reports Server (NTRS)

    Studer, P. A. (Inventor)

    1983-01-01

    A linear magnetic bearing system having electromagnetic vernier flux paths in shunt relation with permanent magnets, so that the vernier flux does not traverse the permanent magnet, is described. Novelty is believed to reside in providing a linear magnetic bearing having electromagnetic flux paths that bypass high reluctance permanent magnets. Particular novelty is believed to reside in providing a linear magnetic bearing with a pair of axially spaced elements having electromagnets for establishing vernier x and y axis control. The magnetic bearing system has possible use in connection with a long life reciprocating cryogenic refrigerator that may be used on the space shuttle.

  2. Experiments on Cryogenic Complex Plasma

    SciTech Connect

    Ishihara, O.; Sekine, W.; Kubota, J.; Uotani, N.; Chikasue, M.; Shindo, M.

    2009-11-10

    Experiments on a cryogenic complex plasma have been performed. Preliminary experiments include production of a plasma in a liquid helium or in a cryogenic helium gas by a pulsed discharge. The extended production of a plasma has been realized in a vapor of liquid helium or in a cryogenic helium gas by rf discharge. The charge of dust particles injected in such a plasma has been studied in detail.

  3. Surface Tension Confines Cryogenic Liquid

    NASA Technical Reports Server (NTRS)

    Castles, Stephen H.; Schein, Michael E.

    1989-01-01

    New type of Dewar provides passive, constant-temperature cryogenic cooling for scientific instruments under normal-to low-gravity conditions. Known as Surface-Tension-Contained Liquid Cryogen Cooler (STCLCC), keeps liquid cryogen in known location inside the Dewar by trapping liquid inside spongelike material. Unique sponge material fills most of volume of inner tank. Sponge is all-silica, open-cell material similar to that used for Space Shuttle thermal-protection tiles.

  4. Coupling of nuclear quadrupole and octupole degrees of freedom in an angular momentum dependent potential of two deformation variables

    SciTech Connect

    Minkov, N.; Yotov, P.; Drenska, S.; Scheid, W.; Bonatsos, Dennis; Lenis, D.; Petrellis, D.

    2006-04-26

    We propose a collective rotation-vibration Hamiltonian of nuclei in which the axial quadrupole {beta}2 and octupole {beta}3 variables are coupled through the centrifugal interaction. We consider that the system oscillates between positive and negative {beta}3-values by rounding a potential core in the ({beta}2,{beta}3)- space. We examine the effect of the 'rounding' in the structure of the spectrum.

  5. Precision Cryogenic Dilatometer

    NASA Technical Reports Server (NTRS)

    Dudik, Matthew; Halverson, Peter; Levine-West, Marie; Marcin, Martin; Peters, Robert D.; Shaklan, Stuart

    2005-01-01

    A dilatometer based on a laser interferometer is being developed to measure mechanical creep and coefficients of thermal expansion (CTEs) of materials at temperatures ranging from ambient down to 15 K. This cryogenic dilatometer has been designed to minimize systematic errors that limit the best previously available dilatometers. At its prototype stage of development, this cryogenic dilatometer yields a strain measurement error of 35 ppb or 1.7 ppb/K CTE measurement error for a 20-K thermal load, for low-expansion materials in the temperature range from 310 down to 30 K. Planned further design refinements that include a provision for stabilization of the laser and addition of a high-precision sample-holding jig are expected to reduce the measurement error to 5-ppb strain error or 0.3-ppb/K CTE error for a 20-K thermal load. The dilatometer (see figure) includes a common-path, differential, heterodyne interferometer; a dual-frequency, stabilized source bench that serves as the light source for the interferometer; a cryogenic chamber in which one places the material sample to be studied; a cryogenic system for cooling the interior of the chamber to the measurement temperature; an ultra-stable alignment stage for positioning the chamber so that the sample is properly positioned with respect to the interferometer; and a data-acquisition and control system. The cryogenic chamber and the interferometer portion of the dilatometer are housed in a vacuum chamber on top of a vibration isolating optical table in a cleanroom. The sample consists of two pieces a pillar on a base both made of the same material. Using reflections of the interferometer beams from the base and the top of the pillar, what is measured is the change in length of the pillar as the temperature in the chamber is changed. In their fundamental optical and electronic principles of operation, the laser light source and the interferometer are similar to those described in Common-Path Heterodyne

  6. Cryogenic Cooling for Myriad Applications-A STAR Is Born

    NASA Technical Reports Server (NTRS)

    2006-01-01

    Cryogenics, the science of generating extremely low temperatures, has wide applicability throughout NASA. The Agency employs cryogenics for rocket propulsion, high-pressure gas supply, breathable air in space, life support equipment, electricity, water, food preservation and packaging, medicine, imaging devices, and electronics. Cryogenic liquid oxygen and liquid hydrogen systems are also replacing solid rocket motor propulsion systems in most of the proposed launch systems, a reversion to old-style liquid propellants. In the late 1980s, NASA wanted a compact linear alternator/motor with reduced size and mass, as well as high efficiency, that had unlimited service life for use in a thermally driven power generator for space power applications. Prior development work with free-piston Stirling converters (a Stirling engine integrated with a linear actuator that produces electrical power output) had shown the promise of that technology for high-power space applications. A dual use for terrestrial applications exists for compact Stirling converters for onsite combined heat and power units. The Stirling cycle is also usable in reverse as a refrigeration cycle suitable for cryogenic cooling, so this Stirling converter work promised double benefits as well as dual uses. The uses for cryogenic coolers within NASA abound; commercial applications are similarly wide-ranging, from cooling liquid oxygen and nitrogen, to cryobiology and bio-storage, cryosurgery, instrument and detector cooling, semiconductor manufacturing, and support service for cooled superconducting power systems.

  7. Cryogenic testing of the TPC superconducting solenoid

    NASA Astrophysics Data System (ADS)

    Green, M. A.; Smits, R. G.; Taylor, J. D.; Vanslyke, V.; Barrera, F.; Petersen, H.; Rago, C. E.; Rinta, R. I.; Talaska, D.; Watt, R. D.

    1983-06-01

    This report describes the results of a series of tests on the TPC superconducting magnet cryogenic system which occurred during the winter and spring of 1983. The tests occurred at interaction region 2 of the PEP colliding beam facility at the Stanford Linear Accelerator Center (SLAC). The TPC Magnet Cryogenic System which was tested includes the following major components: a remote helium compressor with a full flow liquid nitrogen purification station, 400 meters of high pressure supply and low pressure return lines; and locally a CTi Model 2800 refrigerator with two Sulzer gas bearing turbines, the TPC magnet control dewar, 70 meters of transfer lines, and the TPC thin superconducting solenoid magnet. In addition, there is a conditioner (liquid nitrogen heat exchangers and gas heaters) system for cooldown and warmup of the magnet. This report describes the local cryogenic system and describes the various steps in the cooldown and operation of the TPC magnet. The tests were successful in that they showed that the TPC magnet could be cooled down in 24 hours and the magnet could be operated on the refrigerator or a helium pump with adequate cooling margin.

  8. Realization and performance of cryogenic selection mechanisms

    NASA Astrophysics Data System (ADS)

    Aitink-Kroes, Gabby; Bettonvil, Felix; Kragt, Jan; Elswijk, Eddy; Tromp, Niels

    2014-07-01

    Within Infra-Red large wavelength bandwidth instruments the use of mechanisms for selection of observation modes, filters, dispersing elements, pinholes or slits is inevitable. The cryogenic operating environment poses several challenges to these cryogenic mechanisms; like differential thermal shrinkage, physical property change of materials, limited use of lubrication, high feature density, limited space etc. MATISSE the mid-infrared interferometric spectrograph and imager for ESO's VLT interferometer (VLTI) at Paranal in Chile coherently combines the light from 4 telescopes. Within the Cold Optics Bench (COB) of MATISSE two concepts of selection mechanisms can be distinguished based on the same design principles: linear selection mechanisms (sliders) and rotating selection mechanisms (wheels).Both sliders and wheels are used at a temperature of 38 Kelvin. The selection mechanisms have to provide high accuracy and repeatability. The sliders/wheels have integrated tracks that run on small, accurately located, spring loaded precision bearings. Special indents are used for selection of the slider/wheel position. For maximum accuracy/repeatability the guiding/selection system is separated from the actuation in this case a cryogenic actuator inside the cryostat. The paper discusses the detailed design of the mechanisms and the final realization for the MATISSE COB. Limited lifetime and performance tests determine accuracy, warm and cold and the reliability/wear during life of the instrument. The test results and further improvements to the mechanisms are discussed.

  9. The acoustic effect of cryogenically treating trumpets

    NASA Astrophysics Data System (ADS)

    Jones, Jesse; Rogers, Chris

    2003-10-01

    The acoustic effect of cryogenically treating trumpets is investigated. Ten Vincent Bach Stradivarious B♭ trumpets are studied, half of which have been cryogenically treated. The trumpets were played by six players of varying proficiency, with sound samples being recorded directly to disk at a sampling rate of 44.1 kHz. Both the steady-state and initial transient portions of the audio samples are analyzed. When comparing the average power spectra of the treated trumpets to the untreated set, no repeatable, statistically independent differences are observed in the data. Differences observed in player-to-player and trumpet-to-trumpet comparisons overshadow any differences that may have been brought on due to the cryogenic treatment. Qualitatively, players established no clear preference between the treated and untreated trumpets regarding tone and playability, and could not differentiate between the two sets of instruments. All data was collected in a double blind fashion. The treatment itself is a three step process, involving an 8 hour linear cool down period, a 10 hour period of sustained exposure to -195°C (-300°F), and a 20-25 hour period of warming back to room temperature. [Work was completed with the support of Steinway & Sons Pianos and Selmer Musical Instruments.

  10. Cryogenic Scan Mechanism for Fourier Transform Spectrometer

    NASA Technical Reports Server (NTRS)

    Brasunas, John C.; Francis, John L.

    2011-01-01

    A compact and lightweight mechanism has been developed to accurately move a Fourier transform spectrometer (FTS) scan mirror (a cube corner) in a near-linear fashion with near constant speed at cryogenic temperatures. This innovation includes a slide mechanism to restrict motion to one dimension, an actuator to drive the motion, and a linear velocity transducer (LVT) to measure the speed. The cube corner mirror is double-passed in one arm of the FTS; double-passing is required to compensate for optical beam shear resulting from tilting of the moving cube corner. The slide, actuator, and LVT are off-the-shelf components that are capable of cryogenic vacuum operation. The actuator drives the slide for the required travel of 2.5 cm. The LVT measures translation speed. A proportional feedback loop compares the LVT voltage with the set voltage (speed) to derive an error signal to drive the actuator and achieve near constant speed. When the end of the scan is reached, a personal computer reverses the set voltage. The actuator and LVT have no moving parts in contact, and have magnetic properties consistent with cryogenic operation. The unlubricated slide restricts motion to linear travel, using crossed roller bearings consistent with 100-million- stroke operation. The mechanism tilts several arc seconds during transport of the FTS mirror, which would compromise optical fringe efficiency when using a flat mirror. Consequently, a cube corner mirror is used, which converts a tilt into a shear. The sheared beam strikes (at normal incidence) a flat mirror at the end of the FTS arm with the moving mechanism, thereby returning upon itself and compensating for the shear

  11. Search for stable octupole deformation in the nucleus /sup 225/Fr

    SciTech Connect

    Burke, D.G.; Kurcewicz, W.; Loevhoeiden, G.; Nyboe, K.; Thorsteinsen, T.F.; Gietz, H.; Kaffrell, N.; Rogowski, J.; Naumann, R.A.; Borge, M.J.G.; and others

    1987-12-10

    The level structure of /sup 225/Fr has been studied from the /sup 225/Rn(..beta../sup -/) decay in on-line experiments at the ISOLDE facility. A level scheme was constructed on the basis of gamma--gamma coincidence data, and the multipolarities of many transitions were established by conversion electron measurements. Levels in /sup 225/Fr were also studied with the /sup 226/Ra(t,..cap alpha..)/sup 225/Fr reaction at the McMaster University Accelerator Laboratory, using a target of /sup 226/Ra(T/sub 1/2/ = 1600y) and a magnetic spectrograph to analyze the alpha spectra. The first three excited states, at 28.5, 82.5 and 128.2 keV, are interpreted as rotational band members based on the ground state, which is known to have I = 3/2. The (t,..cap alpha..) strengths to these levels indicate a 3/2/sup -/(532) assignment to the ground state. No evidence for an octupole deformation in /sup 225/Fr has been found so far, although analysis of data for other excited states is continuing.

  12. Search for the two-phonon octupole vibrational state in {sup 208}Pb

    SciTech Connect

    Blumenthal, D.J.; Henning, W.; Janssens, R.V.F.

    1995-08-01

    We performed an experiment to search for the two-phonon octupole vibrational state in {sup 208}Pb. Thick targets of {sup 208}Pb, {sup 209}Bi, {sup 58,64}Ni, and {sup 160}Gd were bombarded with 1305 MeV beams of were bombard {sup 208}Pb supplied by ATLAS. Gamma rays were detected using the Argonne-Notre Dame BGO gamma-ray facility, consisting of 12 Compton-suppressed germanium detectors surrounding an array of 50 BGO scintillators. We identified some 30 known gamma rays from {sup 208}Pb in the spectra gated by the 5{sup -} {yields} 3{sup -} and 3{sup -} {yields} 0{sup +} transitions in {sup 208}Pb. In addition, after unfolding these spectra for Compton response, we observed broad coincident structures in the energy region expected for the 2-phonon states. Furthermore, we confirmed the placement of a 2485 keV line observed previously in {sup 207}Pb and find no evidence consistent with the placement of this line in {sup 208}Pb. We are currently in the process of investigating the origin of the broadened lines observed in the spectra, extracting the excitation probability of states in {sup 208}Pb, and determining the relative probability of mutual excitation and neutron transfer in this reaction. An additional experiment is also being performed to collect much higher statistics germanium-germanium coincidence data for the thick {sup 208}Pb target.

  13. Evidence for octupole vibration in the superdeformed well of {sup 190}Hg from eurogam

    SciTech Connect

    Crowell, B.; Carpenter, M.P.; Janssens, R.V.F.

    1995-08-01

    Gammasphere experiments in 1993-94 brought to light the existence of an excited superdeformed (SD) band in {sup 190}Hg with the unusual property of decaying entirely to the lowest (yrast) SD band over 3-4 transitions, rather than to the normally deformed states as is usually the case in the A {approximately} 150 and A {approximately} 190 regions of superdeformation. Although M1 transitions between signature-partner SD bands were previously observed in {sup 193}Hg, no such mechanism was available to explain the situation in the even-even nucleus {sup 190}Hg, whose yrast SD band has no signature partner. The best explanation appears to lie in long-standing theoretical predictions that the SD minimum in the potential energy surface would be quite soft with respect to octupole vibrations. This would lead to enhanced E1 transitions connecting the one-phonon and zero-phonon states. The data and this interpretation were published. A shortcoming of the Gammasphere experiments was that they did not allow the definitive measurement of the energies of the gamma-ray transitions connecting the two bands, due to the very weak population of the excited band ({approximately}0.05% of the {sup 190}Hg channel) and also partly, we believed, to the angular distributions of the transitions, which were peaked near 90 degrees, where Gammasphere had few detectors.

  14. Measuring the Nuclear Magnetic Octupole Moment of a Single Trapped Barium-137 Ion

    NASA Astrophysics Data System (ADS)

    Kleczewski, Adam; Fortson, Norval; Blinov, Boris

    2009-05-01

    Recent measurements of hyperfine structure in the cesium-133 atom resolved a nuclear magnetic octupole moment φ much larger than expected from the nuclear shell model[1]. To explore this issue further, we are undertaking an experiment to measure the hyperfine structure in the 5D manifold of a single trapped barium-137 ion which, together with reliable calculations in alkali-like Ba^+, should resolve φ with sensitivity better than the shell model value [2]. We use a TmHo:YLF laser tuned to 2051 nm and a fiber laser tuned to 1762 nm to drive the 6S1/2 to 5D3/2 and 6S1/2 to 5D5/2 electric quadrupole transitions. These lasers allow us to selectively populate any hyperfine sub-level in the 5D manifold. We will then perform RF spectroscopy on the 5D states to make a precision measurement of the hyperfine frequency intervals. We report on the development of the laser and RF spectroscopy systems. [1] V. Gerginov, A. Derevianko, and C. E. Tanner, Phys. Rev. Lett. 91, 072501 [2] K. Beloy, A. Derevianko, V. A. Dzuba, G. T. Howell, B. B. Blinov, E. N. Fortson, arXiv:0804.4317v1 [physics.atom-ph] 28 Apr 2008

  15. Nuclear Cryogenic Propulsion Stage

    NASA Technical Reports Server (NTRS)

    Houts, Michael G.; Borowski, S. K.; George, J. A.; Kim, T.; Emrich, W. J.; Hickman, R. R.; Broadway, J. W.; Gerrish, H. P.; Adams, R. B.

    2012-01-01

    The fundamental capability of Nuclear Thermal Propulsion (NTP) is game changing for space exploration. A first generation Nuclear Cryogenic Propulsion Stage (NCPS) based on NTP could provide high thrust at a specific impulse above 900 s, roughly double that of state of the art chemical engines. Characteristics of fission and NTP indicate that useful first generation systems will provide a foundation for future systems with extremely high performance. The role of the NCPS in the development of advanced nuclear propulsion systems could be analogous to the role of the DC-3 in the development of advanced aviation. Progress made under the NCPS project could help enable both advanced NTP and advanced NEP.

  16. Cryogenic insulation development

    NASA Technical Reports Server (NTRS)

    Leonhard, K. E.

    1972-01-01

    Multilayer insulations for long term cryogenic storage are described. The development effort resulted in an insulation concept using lightweight radiation shields, separated by low conductive Dacron fiber tufts. The insulation is usually referred to as Superfloc. The fiber tufts are arranged in a triangular pattern and stand about .040 in. above the radiation shield base. Thermal and structural evaluation of Superfloc indicated that this material is a strong candidate for the development of high performance thermal protection systems because of its high strength, purge gas evacuation capability during boost, its density control and easy application to a tank.

  17. Cryogenic support member

    DOEpatents

    Niemann, Ralph C.; Gonczy, John D.; Nicol, Thomas H.

    1987-01-01

    A cryogenic support member is comprised of a non-metallic rod having a depression in at least one end and a metallic end connection assembled to the rod. The metallic end connection comprises a metallic plug which conforms to the shape and is disposed in the depression and a metallic sleeve is disposed over the rod and plug. The plug and the sleeve are shrink-fitted to the depression in the rod to form a connection good in compression, tension and bending.

  18. Refrigerated cryogenic envelope

    DOEpatents

    Loudon, John D.

    1976-11-16

    An elongated cryogenic envelope including an outer tube and an inner tube coaxially spaced within said inner tube so that the space therebetween forms a vacuum chamber for holding a vacuum. The inner and outer tubes are provided with means for expanding or contracting during thermal changes. A shield is located in the vacuum chamber intermediate the inner and outer tubes; and, a refrigeration tube for directing refrigeration to the shield is coiled about at least a portion of the inner tube within the vacuum chamber to permit the refrigeration tube to expand or contract along its length during thermal changes within said vacuum chamber.

  19. Cryogenic Propellant Scavenging

    NASA Technical Reports Server (NTRS)

    Louie, B.; Kemp, N. J.; Daney, D. E.

    1985-01-01

    A detailed description of a computer model that has been developed for assessing the feasibility of low g cryogen propellant scavenging from the space shuttle External Tank (ET) is given. Either pump-assisted or pressure-induced propellant transfer may be selected. The program will accept a wide range of input variables, including the fuel to be transferred (LOX or LH2), heat leaks, tank temperatures, and piping and equipment specifications. The model has been parametrically analyzed to determine initial design specification for the system.

  20. FRIB cryogenic distribution system

    NASA Astrophysics Data System (ADS)

    Ganni, V.; Dixon, K.; Laverdure, N.; Knudsen, P.; Arenius, D.; Barrios, M.; Jones, S.; Johnson, M.; Casagrande, F.

    2014-01-01

    The Michigan State University Facility for Rare Isotope Beams (MSU-FRIB) helium distribution system has been revised to include bayonet/warm valve type disconnects between each cryomodule and the transfer line distribution system, similar to the Thomas Jefferson National Accelerator Facility (JLab) and the Spallation Neutron Source (SNS) cryogenic distribution systems. The heat loads at various temperature levels and some of the features in the design of the distribution system are outlined. The present status, the plans for fabrication, and the procurement approach for the helium distribution system are also included.

  1. Optical Detection Of Cryogenic Leaks

    NASA Technical Reports Server (NTRS)

    Wyett, Lynn M.

    1988-01-01

    Conceptual system identifies leakage without requiring shutdown for testing. Proposed device detects and indicates leaks of cryogenic liquids automatically. Detector makes it unnecessary to shut equipment down so it can be checked for leakage by soap-bubble or helium-detection methods. Not necessary to mix special gases or other materials with cryogenic liquid flowing through equipment.

  2. Kodak AMSD Cryogenic Test Plans

    NASA Technical Reports Server (NTRS)

    Matthews, Gary; Hammon, John; Barrett, David; Russell, Kevin (Technical Monitor)

    2002-01-01

    NGST will be an IR based optical system that will operate at cryogenic temperatures. As part of the AMSD program, Kodak must demonstrate the ability of our system to perform at these very cold temperatures. Kodak will discuss the test approach that will be used for cryogenic testing at MSFC's XRCF.

  3. Electromechanical Materials for Cryogenic Use

    NASA Technical Reports Server (NTRS)

    Leidinger, Peter; Pilgrim, Steven M.

    1996-01-01

    Electromechanical materials can be used in smart sensor and actuator devices. Yet none performing at low temperatures are available. To meet this need, Pb((MgNi)(1/3)Ta(2/3))03 was synthesized as an electrostrictive ceramic for applications in cryogenic environments. Employing the columbite precursor route, samples with 0% to 100% Ni substitution for Mg were prepared, but only samples with Ni-substitutions less than or equal to 20% yielded primarily the desired perovskite phase. For these compositions the temperature of highest permittivity decreased linearly with increasing Ni content to yield a minimum value of -124 C for 20% Ni-substitution. This composition showed good relaxor dielectric behavior with a maximum relative permittivity of 5890 at 1 kHz. Additionally, in samples with excess MgO, the magnitude of permittivity doubled. In this effort, Pb((MgNi)(1/3)Ta(2/3))03 (PMNiTa) was fabricated to lower its transition temperature by substituting Ni for Mg successively.

  4. Development of a cryogenic microcalorimeter

    NASA Astrophysics Data System (ADS)

    Junkin, David Stuart

    The motivation for this project has been to measure β-decay using a low background detector which encapsulated the β source (4π coverage). It was realized that the ideal detector for this measurement was a microcalorimeter (a small cryogenic detector consisting of an absorber, thermistor and thermal link). Presently microcalorimeters are an active area of research and development because of possible applications in weak interaction physics, x-ray astronomy and dark matter searches. The development of such a detector requires an interdisciplinary effort involving nuclear physics, solid state physics, electronics, and statistical mechanics. We have designed, constructed and characterized microcalorimeters employing two types of thermistors (AuxGe(x-1) and P:Si). In the process we constructed a dilution refrigerator, assembled the necessary electronics, and built a data acquisition and analysis system based on networked desktop computers. This stage of the project has concluded by characterizing the performance of the AuxGe(x-1) based microcalorimeters by measuring /alpha s and low energy /gamma s. The measured energy spectra have been compared to theoretical predictions, and the linearity of the devices has been tested. Future work will permit these devices to be used to measure β spectra.

  5. Cryogenic System for the Cryomodule Test Stand at Fermilab

    NASA Astrophysics Data System (ADS)

    White, Michael; Hansen, Benjamin; Klebaner, Arkadiy

    2015-12-01

    This paper describes the cryogenic system for the Cryomodule Test Stand (CMTS) at the new Cryomodule Test Facility (CMTF) located at Fermilab. CMTS is designed for production testing of the 1.3 GHz and 3.9GHz cryomodules to be used in the Linac Coherent Light Source II (LCLSII), which is an upgrade to an existing accelerator at Stanford Linear Accelerator Laboratory (SLAC). This paper will focus on the cryogenic system that extends from the helium refrigeration plant to the CMTS cave. Topics covered will include component design, installation and commissioning progress, and operational plans. The paper will conclude with a description of the heat load measurement plan.

  6. Cryogenic Piezoelectric Actuator

    NASA Technical Reports Server (NTRS)

    Jiang, Xiaoning; Cook, William B.; Hackenberger, Wesley S.

    2009-01-01

    In this paper, PMN-PT single crystal piezoelectric stack actuators and flextensional actuators were designed, prototyped and characterized for space optics applications. Single crystal stack actuators with footprint of 10 mm x10 mm and the height of 50 mm were assembled using 10 mm x10mm x0.15mm PMN-PT plates. These actuators showed stroke > 65 - 85 microns at 150 V at room temperature, and > 30 microns stroke at 77 K. Flextensional actuators with dimension of 10mm x 5 mm x 7.6 mm showed stroke of >50 microns at room temperature at driving voltage of 150 V. A flextensional stack actuator with dimension of 10 mm x 5 mm x 47 mm showed stroke of approx. 285 microns at 150 V at room temperature and > 100 microns at 77K under driving of 150 V should be expected. The large cryogenic stroke and high precision of these actuators are promising for cryogenic optics applications.

  7. Cryogenics maintenance strategy

    NASA Astrophysics Data System (ADS)

    Cruzat, Fabiola

    2012-09-01

    ALMA is an interferometer composed of 66 independent systems, with specific maintenance requirements for each subsystem. To optimize the observation time and reduce downtime maintenance, requirements are very demanding. One subsystem with high maintenance efforts is cryogenics and vacuum. To organize the maintenance, the Cryogenic and Vacuum department is using and implementing different tools. These are monitoring and problem reporting systems and CMMS. This leads to different maintenance approaches: Preventive Maintenance, Corrective Maintenance and Condition Based Maintenance. In order to coordinate activities with other departments the preventive maintenance schedule is kept as flexible as systems allow. To cope with unavoidable failures, the team has to be prepared to work under any condition with the spares on time. Computerized maintenance management system (CMMS) will help to manage inventory control for reliable spare part handling, the correct record of work orders and traceability of maintenance activities. For an optimized approach the department is currently evaluating where preventive or condition based maintenance applies to comply with the individual system demand. Considering the change from maintenance contracts to in-house maintenance will help to minimize costs and increase availability of parts. Due to increased number of system and tasks the cryo team needs to grow. Training of all staff members is mandatory, in depth knowledge must be built up by doing complex maintenance activities in the Cryo group, use of advanced computerized metrology systems.

  8. Cryogenic fluid management experiment

    NASA Technical Reports Server (NTRS)

    Eberhardt, R. N.; Bailey, W. J.; Fester, D. A.

    1981-01-01

    The cryogenic fluid management experiment (CFME), designed to characterize subcritical liquid hydrogen storage and expulsion in the low-q space environment, is discussed. The experiment utilizes a fine mesh screen fluid management device to accomplish gas-free liquid expulsion and a thermodynamic vent system to intercept heat leak and control tank pressure. The experiment design evolved from a single flight prototype to provision for a multimission (up to 7) capability. A detailed design of the CFME, a dynamic test article, and dedicated ground support equipment were generated. All materials and parts were identified, and components were selected and specifications prepared. Long lead titanium pressurant spheres and the flight tape recorder and ground reproduce unit were procured. Experiment integration with the shuttle orbiter, Spacelab, and KSC ground operations was coordinated with the appropriate NASA centers, and experiment interfaces were defined. Phase 1 ground and flight safety reviews were conducted. Costs were estimated for fabrication and assembly of the CFME, which will become the storage and supply tank for a cryogenic fluid management facility to investigate fluid management in space.

  9. Cryogenic skirt support post

    NASA Astrophysics Data System (ADS)

    Niemann, R. C.; Buckles, W. E.

    The cold masses of cryostats having vertical axes, like vertical pressure vessels, can be effectively supported by means of a cylindrical skirt that wraps concentrically around the cold mass. The skirt is a cryogenic support post connected at its upper end to the cold mass and at its lower end to the cryostat vacuum vessel. A heat intercept connection to an intermediate temperature refrigeration source can be employed to control heat leak. The support post consists of a composite; e.g. epoxy fibreglass, or cylinder with bolted or thermal interference fit end connections. The support post, being a single element support, simplifies cryostat assembly and alignment. The composite cylinder, with a relatively large diameter, lends itself to structural soundness and stability under both static and dynamic loading conditions. Its relatively long length and intermediate temperature heat intercept allows low heat leak to the cold mass. The details of the design of a cryogenic skirt support post as applied to a superconducting magnetic energy storage cryostat are presented. Included are support post fabrication, cryostat assembly, and predicted structural and thermal performance. Fabrication of and operational experiences with a prototype support post assembly are discussed.

  10. A cryogenic optical feedthrough using polarization maintaining fibers.

    PubMed

    Nelson, M J; Collins, C J; Speake, C C

    2016-03-01

    Polarization maintaining optical fibers can be used to transmit linearly polarized light over long distances but their use in cryogenic environments has been limited by their sensitivity to temperature changes and associated mechanical stress. We investigate experimentally how thermal stresses affect the polarization maintaining fibers and model the observations with Jones matrices. We describe the design, construction, and testing of a feedthrough and fiber termination assembly that uses polarization maintaining fiber to transmit light from a 633 nm HeNe laser at room temperature to a homodyne polarization-based interferometer in a cryogenic vacuum. We report on the efficiency of the polarization maintaining properties of the feedthrough assembly. We also report that, at cryogenic temperatures, the interferometer can achieve a sensitivity of 8 × 10(-10) rad/Hz at 0.05 Hz using this feedthrough. PMID:27036762

  11. A cryogenic optical feedthrough using polarization maintaining fibers

    NASA Astrophysics Data System (ADS)

    Nelson, M. J.; Collins, C. J.; Speake, C. C.

    2016-03-01

    Polarization maintaining optical fibers can be used to transmit linearly polarized light over long distances but their use in cryogenic environments has been limited by their sensitivity to temperature changes and associated mechanical stress. We investigate experimentally how thermal stresses affect the polarization maintaining fibers and model the observations with Jones matrices. We describe the design, construction, and testing of a feedthrough and fiber termination assembly that uses polarization maintaining fiber to transmit light from a 633 nm HeNe laser at room temperature to a homodyne polarization-based interferometer in a cryogenic vacuum. We report on the efficiency of the polarization maintaining properties of the feedthrough assembly. We also report that, at cryogenic temperatures, the interferometer can achieve a sensitivity of 8 × 10-10 rad/ √{ Hz } at 0.05 Hz using this feedthrough.

  12. Ultrastable Cryogenic Microwave Oscillators

    NASA Astrophysics Data System (ADS)

    Mann, Anthony G.

    Ultrastable cryogenic microwave oscillators are secondary frequency standards in the microwave domain. The best of these oscillators have demonstrated a short term frequency stability in the range 10-14 to a few times 10-16. The main application for these oscillators is as flywheel oscillators for the next generation of passive atomic frequency standards, and as local oscillators in space telemetry ground stations to clean up the transmitter close in phase noise. Fractional frequency stabilities of passive atomic frequency standards are now approaching 3 x10^-14 /τ where τ is the measurement time, limited only by the number of atoms that are being interrogated. This requires an interrogation oscillator whose short-term stability is of the order of 10-14 or better, which cannot be provided by present-day quartz technology. Ultrastable cryogenic microwave oscillators are based on resonators which have very high electrical Q-factors. The resolution of the resonator's linewidth is typically limited by electronics noise to about 1ppm and hence Q-factors in excess of 108 are required. As these are only attained in superconducting cavities or sapphire resonators at low temperatures, use of liquid helium cooling is mandatory, which has so far restricted these oscillators to the research or metrology laboratory. Recently, there has been an effort to dispense with the need for liquid helium and make compact flywheel oscillators for the new generation of primary frequency standards. Work is under way to achieve this goal in space-borne and mobile liquid-nitrogen-cooled systems. The best cryogenic oscillators developed to date are the ``whispering gallery'' (WG) mode sapphire resonator-oscillators of NASA's Jet Propulsion Laboratory (JPL) and the University of Western Australia (UWA), as well as Stanford University's superconducting cavity stabilized oscillator (SCSO). All of these oscillators have demonstrated frequency

  13. Capacitive Sensors for Measuring Masses of Cryogenic Fluids

    NASA Technical Reports Server (NTRS)

    Nurge, Mark; Youngquist, Robert

    2003-01-01

    An effort is under way to develop capacitive sensors for measuring the masses of cryogenic fluids in tanks. These sensors are intended to function in both microgravitational and normal gravitational settings, and should not be confused with level sensors, including capacitive ones. A sensor of this type is conceptually simple in the sense that (1) it includes only one capacitor and (2) if properly designed, its single capacitance reading should be readily convertible to a close approximation of the mass of the cryogenic fluid in the tank. Consider a pair of electrically insulated electrodes used as a simple capacitive sensor. In general, the capacitance is proportional to the permittivity of the dielectric medium (in this case, a cryogenic fluid) between the electrodes. The success of design and operation of a sensor of the present type depends on the accuracy of the assumption that to a close approximation, the permittivity of the cryogenic fluid varies linearly with the density of the fluid. Data on liquid nitrogen, liquid oxygen, and liquid hydrogen, reported by the National Institute of Standards and Technology, indicate that the permittivities and densities of these fluids are, indeed, linearly related to within a few tenths of a percent over the pressure and temperature regions of interest. Hence, ignoring geometric effects for the moment, the capacitance between two electrodes immersed in the fluid should vary linearly with the density, and, hence, with the mass of the fluid. Of course, it is necessary to take account of the tank geometry. Because most cryogenic tanks do not have uniform cross sections, the readings of level sensors, including capacitive ones, are not linearly correlated with the masses of fluids in the tanks. In a sensor of the present type, the capacitor electrodes are shaped so that at a given height, the capacitance per unit height is approximately proportional to the cross-sectional area of the tank in the horizontal plane at that

  14. Decay of quadrupole-octupole 1- states in 40Ca and 140Ce

    NASA Astrophysics Data System (ADS)

    Derya, V.; Tsoneva, N.; Aumann, T.; Bhike, M.; Endres, J.; Gooden, M.; Hennig, A.; Isaak, J.; Lenske, H.; Löher, B.; Pietralla, N.; Savran, D.; Tornow, W.; Werner, V.; Zilges, A.

    2016-03-01

    Background: Two-phonon excitations originating from the coupling of two collective one-phonon states are of great interest in nuclear structure physics. One possibility to generate low-lying E 1 excitations is the coupling of quadrupole and octupole phonons. Purpose: In this work, the γ -decay behavior of candidates for the (21+⊗31-)1- state in the doubly magic nucleus 40Ca and in the heavier and semimagic nucleus 140Ce is investigated. Methods: (γ ⃗,γ') experiments have been carried out at the High Intensity γ -ray Source (HI γ S ) facility in combination with the high-efficiency γ -ray spectroscopy setup γ3 consisting of HPGe and LaBr3 detectors. The setup enables the acquisition of γ -γ coincidence data and, hence, the detection of direct decay paths. Results: In addition to the known ground-state decays, for 40Ca the decay into the 31- state was observed, while for 140Ce the direct decays into the 21+ and the 02+ state were detected. The experimentally deduced transition strengths and excitation energies are compared to theoretical calculations in the framework of EDF theory plus QPM approach and systematically analyzed for N =82 isotones. In addition, negative parities for two J =1 states in 44Ca were deduced simultaneously. Conclusions: The experimental findings together with the theoretical calculations support the two-phonon character of the 11- excitation in the light-to-medium-mass nucleus 40Ca as well as in the stable even-even N =82 nuclei.

  15. Cryogenic Fluid Transfer for Exploration

    NASA Technical Reports Server (NTRS)

    Chato, David J.

    2008-01-01

    This paper discusses current plans and issues for exploration that involve the use of cryogenic transfer. The benefits of cryogenic transfer to exploration missions are examined. The current state of the art of transfer technology is reviewed. Mission concepts of operation for exploration are presented, and used to qualitatively discuss the performance benefits of transfer. The paper looks at the challenges faced to implement a cryogenic transfer system and suggest approaches to address them with advanced development research. Transfer rates required for exploration are shown to have already been achieved in ground test. Cost-effective approaches to the required on-orbit demonstration are suggested.

  16. Cryogenic Fluid Transfer for Exploration

    NASA Technical Reports Server (NTRS)

    Chato, David J.

    2007-01-01

    This paper discusses current plans and issues for exploration that involve the use of cryogenic transfer. The benefits of cryogenic transfer to exploration missions are examined. The current state of the art of transfer technology is reviewed. Mission concepts of operation for exploration are presented, and used to qualitatively discuss the performance benefits of transfer. The paper looks at the challenges faced to implement a cryogenic transfer system and suggest approaches to address them with advanced development research. Transfer rates required for exploration are shown to have already been achieved in ground test. Cost effective approaches to the required on-orbit demonstration are suggested.

  17. Radiation requirements and testing of cryogenic thermometers for the ILC

    SciTech Connect

    Barnett, T.; Filippov, Yu.P.; Mokhov, N.V.; Nakao, N.; Klebaner, A.L.; Korenev, S.A.; Theilacker, J.C. /; Trenikhina, J.; Vaziri, K.; /Fermilab

    2007-07-01

    Large quantity of cryogenic temperature sensors will be used for operation of the International Linear Collider (ILC). Most of them will be subject to high radiation doses during the accelerator lifetime. Understanding of particle energy spectra, accumulated radiation dose in thermometers and its impact on performance are vital in establishing technical specification of cryogenic thermometry for the ILC. Realistic MARS15 computer simulations were performed to understand the ILC radiation environment. Simulation results were used to establish radiation dose requirements for commercially available cryogenic thermometers. Two types of thermometers, Cernox{reg_sign} and TVO, were calibrated prior to irradiation using different technique. The sensors were subjected then to up to 200 kGy electron beam irradiation with kinetic energy of 5 MeV, a representative of the situation at the ILC operation. A post-irradiation behavior of the sensors was studied. The paper describes the MARS15 model, simulation results, cryogenic test set-up, irradiation tests, and cryogenic test results.

  18. Cryogenic Infrastructure for Fermilab's Ilc Vertical Cavity Test Facility

    NASA Astrophysics Data System (ADS)

    Carcagno, R.; Ginsburg, C.; Huang, Y.; Norris, B.; Ozelis, J.; Peterson, T.; Poloubotko, V.; Rabehl, R.; Sylvester, C.; Wong, M.

    2008-03-01

    Fermilab is building a Vertical Cavity Test Facility (VCTF) to provide for R&D and pre-production testing of bare 9-cell, 1.3-GHz superconducting RF (SRF) cavities for the International Linear Collider (ILC) program. This facility is located in the existing Industrial Building 1 (IB1) where the Magnet Test Facility (MTF) also resides. Helium and nitrogen cryogenics are shared between the VCTF and MTF including the existing 1500-W at 4.5-K helium refrigerator with vacuum pumping for super-fluid operation (125-W capacity at 2-K). The VCTF is being constructed in multiple phases. The first phase is scheduled for completion in mid 2007, and includes modifications to the IB1 cryogenic infrastructure to allow helium cooling to be directed to either the VCTF or MTF as scheduling demands require. At this stage, the VCTF consists of one Vertical Test Stand (VTS) cryostat for the testing of one cavity in a 2-K helium bath. Planning is underway to provide a total of three Vertical Test Stands at VCTF, each capable of accommodating two cavities. Cryogenic infrastructure improvements necessary to support these additional VCTF test stands include a dedicated ambient temperature vacuum pump, a new helium purification skid, and the addition of helium gas storage. This paper describes the system design and initial cryogenic operation results for the first VCTF phase, and outlines future cryogenic infrastructure upgrade plans for expanding to three Vertical Test Stands.

  19. CRYOGENIC INFRASTRUCTURE FOR FERMILAB'S ILC VERTICAL CAVITY TEST FACILITY

    SciTech Connect

    Carcagno, R.; Ginsburg, C.; Huang, Y.; Norris, B.; Ozelis, J.; Peterson, T.; Poloubotko, V.; Rabehl, R.; Sylvester, C.; Wong, M.

    2008-03-16

    Fermilab is building a Vertical Cavity Test Facility (VCTF) to provide for R and D and pre-production testing of bare 9-cell, 1.3-GHz superconducting RF (SRF) cavities for the International Linear Collider (ILC) program. This facility is located in the existing Industrial Building 1 (IB1) where the Magnet Test Facility (MTF) also resides. Helium and nitrogen cryogenics are shared between the VCTF and MTF including the existing 1500-W at 4.5-K helium refrigerator with vacuum pumping for super-fluid operation (125-W capacity at 2-K). The VCTF is being constructed in multiple phases. The first phase is scheduled for completion in mid 2007, and includes modifications to the IB1 cryogenic infrastructure to allow helium cooling to be directed to either the VCTF or MTF as scheduling demands require. At this stage, the VCTF consists of one Vertical Test Stand (VTS) cryostat for the testing of one cavity in a 2-K helium bath. Planning is underway to provide a total of three Vertical Test Stands at VCTF, each capable of accommodating two cavities. Cryogenic infrastructure improvements necessary to support these additional VCTF test stands include a dedicated ambient temperature vacuum pump, a new helium purification skid, and the addition of helium gas storage. This paper describes the system design and initial cryogenic operation results for the first VCTF phase, and outlines future cryogenic infrastructure upgrade plans for expanding to three Vertical Test Stands.

  20. Cryogenic infrastructure for Fermilab's ILC vertical cavity test facility

    SciTech Connect

    Carcagno, R.; Ginsburg, C.; Huang, Y.; Norris, B.; Ozelis, J.; Peterson, T.; Poloubotko, V.; Rabehl, R.; Sylvester, C.; Wong, M.; /Fermilab

    2006-06-01

    Fermilab is building a Vertical Cavity Test Facility (VCTF) to provide for R&D and pre-production testing of bare 9-cell, 1.3-GHz superconducting RF (SRF) cavities for the International Linear Collider (ILC) program. This facility is located in the existing Industrial Building 1 (IB1) where the Magnet Test Facility (MTF) also resides. Helium and nitrogen cryogenics are shared between the VCTF and MTF including the existing 1500-W at 4.5-K helium refrigerator with vacuum pumping for super-fluid operation (125-W capacity at 2-K). The VCTF is being constructed in multiple phases. The first phase is scheduled for completion in mid 2007, and includes modifications to the IB1 cryogenic infrastructure to allow helium cooling to be directed to either the VCTF or MTF as scheduling demands require. At this stage, the VCTF consists of one Vertical Test Stand (VTS) cryostat for the testing of one cavity in a 2-K helium bath. Planning is underway to provide a total of three Vertical Test Stands at VCTF, each capable of accommodating two cavities. Cryogenic infrastructure improvements necessary to support these additional VCTF test stands include a dedicated ambient temperature vacuum pump, a new helium purification skid, and the addition of helium gas storage. This paper describes the system design and initial cryogenic operation results for the first VCTF phase, and outlines future cryogenic infrastructure upgrade plans for expanding to three Vertical Test Stands.

  1. Cryogenic expansion machine

    DOEpatents

    Pallaver, Carl B.; Morgan, Michael W.

    1978-01-01

    A cryogenic expansion engine includes intake and exhaust poppet valves each controlled by a cam having adjustable dwell, the valve seats for the valves being threaded inserts in the valve block. Each cam includes a cam base and a ring-shaped cam insert disposed at an exterior corner of the cam base, the cam base and cam insert being generally circular but including an enlarged cam dwell, the circumferential configuration of the cam base and cam dwell being identical, the cam insert being rotatable with respect to the cam base. GI CONTRACTUAL ORIGIN OF THE INVENTION The invention described herein was made in the course of, or under, a contract with the UNITED STATES ENERGY RESEARCH AND DEVELOPMENT ADMINISTRATION.

  2. Basic cryogenics and materials

    NASA Technical Reports Server (NTRS)

    Wigley, D. A.

    1985-01-01

    The effects of cryogenic temperatures on the mechanical and physical properties of materials are summarized. Heat capacity and thermal conductivity are considered in the context of conservation of liquid nitrogen, thermal stability of the gas stream, and the response time for changes in operating temperature. Particular attention is given to the effects of differential expansion and failure due to thermal fatigue. Factors affecting safety are discussed, including hazards created due to the inadvertent production of liquid oxygen and the physiological effects of exposure to liquid and gaseous nitrogen, such as cold burns and asphyxiation. The preference for using f.c.c. metals at low temperatures is explained in terms of their superior toughness. The limitations on the use of ferritic steels is also considered. Nonmetallic materials are discussed, mainly in the context of their LOX compatibility and their use in the form of foams and fibers as insulatants, seals, and fiber reinforced composites.

  3. LUX Cryogenics and Circulation

    NASA Astrophysics Data System (ADS)

    Bradley, Adam

    2012-10-01

    LUX is a new dark matter direct detection experiment being carried out at the Sanford Underground Research Facility, at the renewed Homestake mine in Lead, SD. The detector's large size supports effective internal shielding from natural radioactivity of the surrounding materials and environment. The LUX detector consists of a cylindrical vessel containing 350 kg of liquid xenon (LXe) cooled down and maintained at 175-K operating temperature using a novel cryogenic system. We report the efficiency of our thermosyphon-based cooling system, as well as the efficiency of a unique internal heat exchanger with standard gas phase purification using a heated getter, which allows for very high flow purification without requiring large cooling power. Such systems are required for multi-ton scale up.

  4. Cryogenic cooler apparatus

    DOEpatents

    Wheatley, John C.; Paulson, Douglas N.; Allen, Paul C.

    1983-01-01

    A Malone-type final stage for utilization in a Stirling cycle cryogenic cooler apparatus includes a displacer slidable within a vessel. .sup.4 He, .sup.3 He, or a mixture thereof is made to flow in a pulsating unidirectional manner through a regenerator in the displacer by utilization of check valves in separate fluid channels. Stacked copper screen members extend through the channels and through a second static thermodynamic medium within the displacer to provide efficient lateral heat exchange and enable cooling to temperatures in the range of 3-4 K. Another embodiment utilizes sintered copper particles in the regenerator. Also described is a final stage that has a non-thermally conducting displacer having passages with check valves for directing fluid past a regenerator formed in the surrounding vessel.

  5. Cryogenic Propulsion Stage

    NASA Technical Reports Server (NTRS)

    Jones, David

    2011-01-01

    The CPS is an in-space cryogenic propulsive stage based largely on state of the practice design for launch vehicle upper stages. However, unlike conventional propulsive stages, it also contains power generation and thermal control systems to limit the loss of liquid hydrogen and oxygen due to boil-off during extended in-space storage. The CPS provides the necessary (Delta)V for rapid transfer of in-space elements to their destinations or staging points (i.e., E-M L1). The CPS is designed around a block upgrade strategy to provide maximum mission/architecture flexibility. Block 1 CPS: Short duration flight times (hours), passive cryo fluid management. Block 2 CPS: Long duration flight times (days/weeks/months), active and passive cryo fluid management.

  6. Cryogenic cooler apparatus

    DOEpatents

    Wheatley, J.C.; Paulson, D.N.; Allen, P.C.

    1983-01-04

    A Malone-type final stage for utilization in a Stirling cycle cryogenic cooler apparatus includes a displacer slidable within a vessel. [sup 4]He, [sup 3]He, or a mixture thereof is made to flow in a pulsating unidirectional manner through a regenerator in the displacer by utilization of check valves in separate fluid channels. Stacked copper screen members extend through the channels and through a second static thermodynamic medium within the displacer to provide efficient lateral heat exchange and enable cooling to temperatures in the range of 3--4 K. Another embodiment utilizes sintered copper particles in the regenerator. Also described is a final stage that has a non-thermally conducting displacer having passages with check valves for directing fluid past a regenerator formed in the surrounding vessel. 10 figs.

  7. Cosmic flows on 100 h-1 Mpc scales: standardized minimum variance bulk flow, shear and octupole moments

    NASA Astrophysics Data System (ADS)

    Feldman, Hume A.; Watkins, Richard; Hudson, Michael J.

    2010-10-01

    The low-order moments, such as the bulk flow and shear, of the large-scale peculiar velocity field are sensitive probes of the matter density fluctuations on very large scales. In practice, however, peculiar velocity surveys are usually sparse and noisy, which can lead to the aliasing of small-scale power into what is meant to be a probe of the largest scales. Previously, we developed an optimal `minimum variance' (MV) weighting scheme, designed to overcome this problem by minimizing the difference between the measured bulk flow (BF) and that which would be measured by an ideal survey. Here we extend this MV analysis to include the shear and octupole moments, which are designed to have almost no correlations between them so that they are virtually orthogonal. We apply this MV analysis to a compilation of all major peculiar velocity surveys, consisting of 4536 measurements. Our estimate of the BF on scales of ~100h-1Mpc has a magnitude of |v| = 416 +/- 78 kms -1 towards Galactic l = 282° +/- 11° and b = 6° +/- 6°. This result is in disagreement with Λ cold dark matter with Wilkinson Microwave Anisotropy Probe 5 (WMAP5) cosmological parameters at a high confidence level, but is in good agreement with our previous MV result without an orthogonality constraint, showing that the shear and octupole moments did not contaminate the previous BF measurement. The shear and octupole moments are consistent with WMAP5 power spectrum, although the measurement noise is larger for these moments than for the BF. The relatively low shear moments suggest that the sources responsible for the BF are at large distances.

  8. Octupole degree of freedom for the critical-point candidate nucleus {sup 152}Sm in a reflection-asymmetric relativistic mean-field approach

    SciTech Connect

    Zhang, W.; Li, Z. P.; Zhang, S. Q.; Meng, J.

    2010-03-15

    The potential energy surfaces of even-even {sup 146-156}Sm are investigated in the constrained reflection-asymmetric relativistic mean-field approach with parameter set PK1. It is shown that the critical-point candidate nucleus {sup 152}Sm marks the shape/phase transition not only from U(5) to SU(3) symmetry, but also from the octupole-deformed ground state in {sup 150}Sm to the quadrupole-deformed ground state in {sup 154}Sm. By including the octupole degree of freedom, an energy gap near the Fermi surface for single-particle levels in {sup 152}Sm with beta{sub 2}=0.14approx0.26 is found and the important role of the octupole deformation driving pair nu2f{sub 7/2} and nu1i{sub 13/2} is demonstrated.

  9. 34. mu. s isomer at high spin in sup 212 Fr: Evidence for a many-particle octupole coupled state

    SciTech Connect

    Byrne, A.P.; Dracoulis, G.D.; Schiffer, K.J.; Davidson, P.M.; Kibedi, T.; Fabricius, B.; Baxter, A.M.; Stuchbery, A.E. Australian National University, G.P.O. Box 4, Canberra, Australian Capital Territory )

    1990-07-01

    A very high spin isomeric state with {tau}{sub {ital m}}=34(3) {mu}s has been observed at an excitation energy of 8.5 MeV in {sup 212}Fr. The experimental evidence favors an {ital E}3 assignment, with a very large {ital E}3 transition strength, {ital B}({ital E}3)=100(12){times}10{sup 3} {ital e}{sup 2}fm{sup 6}, to one of the {gamma} rays de-exciting the isomer. The observed properties are in very good agreement with the characteristics of a 34{sup +} state predicted by the multiparticle octupole vibration model.

  10. Interference between selected dipoles and octupoles in the optical second-harmonic generation from spherical gold nanoparticles.

    PubMed

    Butet, J; Bachelier, G; Russier-Antoine, I; Jonin, C; Benichou, E; Brevet, P-F

    2010-08-13

    Optical second-harmonic generation from gold nanoparticles is investigated both experimentally and theoretically. The contribution of octupoles is reported for the first time in the second-harmonic emission pattern, by using an harmonic polarization in the scattering plane. The experimental results presented here for particle sizes up to 100 nm are in excellent agreement with finite element method simulations involving the normal surface term only in the nonlinear polarization source. In addition, analytical calculations based on nonlinear Mie scattering theory clearly evidence the constructive and destructive interferences occurring between the dipolar and octupolar responses selected with this polarization configuration. PMID:20868074

  11. Introduction to cryogenic wind tunnels

    NASA Technical Reports Server (NTRS)

    Goodyer, M. J.

    1985-01-01

    The background to the evolution of the cryogenic wind tunnel is outlined, with particular reference to the late 60's/early 70's when efforts were begun to re-equip with larger wind tunnels. The problems of providing full scale Reynolds numbers in transonic testing were proving particularly intractible, when the notion of satisfying the needs with the cryogenic tunnel was proposed, and then adopted. The principles and advantages of the cryogenic tunnel are outlined, along with guidance on the coolant needs when this is liquid nitrogen, and with a note on energy recovery. Operational features of the tunnels are introduced with reference to a small low speed tunnel. Finally the outstanding contributions are highlighted of the 0.3-Meter Transonic Cryogenic Tunnel (TCT) at NASA Langley Research Center, and its personnel, to the furtherance of knowledge and confidence in the concept.

  12. A Piezoelectric Cryogenic Heat Switch

    NASA Technical Reports Server (NTRS)

    Jahromi, Amir E.; Sullivan, Dan F.

    2014-01-01

    We have measured the thermal conductance of a mechanical heat switch actuated by a piezoelectric positioner, the PZHS (PieZo electric Heat Switch), at cryogenic temperatures. The thermal conductance of the PZHS was measured between 4 K and 10 K, and on/off conductance ratios greater than 100 were achieved when the positioner applied its maximum force of 8 N. We discuss the advantages of using this system in cryogenic applications, and estimate the ultimate performance of an optimized PZHS.

  13. Cryogenic High Pressure Sensor Module

    NASA Technical Reports Server (NTRS)

    Chapman, John J. (Inventor); Shams, Qamar A. (Inventor); Powers, William T. (Inventor)

    1999-01-01

    A pressure sensor is provided for cryogenic, high pressure applications. A highly doped silicon piezoresistive pressure sensor is bonded to a silicon substrate in an absolute pressure sensing configuration. The absolute pressure sensor is bonded to an aluminum nitride substrate. Aluminum nitride has appropriate coefficient of thermal expansion for use with highly doped silicon at cryogenic temperatures. A group of sensors, either two sensors on two substrates or four sensors on a single substrate are packaged in a pressure vessel.

  14. Cryogenic foam insulation: Abstracted publications

    NASA Technical Reports Server (NTRS)

    Williamson, F. R.

    1977-01-01

    A group of documents were chosen and abstracted which contain information on the properties of foam materials and on the use of foams as thermal insulation at cryogenic temperatures. The properties include thermal properties, mechanical properties, and compatibility properties with oxygen and other cryogenic fluids. Uses of foams include applications as thermal insulation for spacecraft propellant tanks, and for liquefied natural gas storage tanks and pipelines.

  15. The RHIC cryogenic control system

    SciTech Connect

    Farah, Y.; Sondericker, J.

    1993-08-01

    A cryogenic process control system for the RHIC Project is discussed. It is independent of the main RHIC Control System, consisting of an upgrade of the existing 24.8 Kw helium refrigerator control section with the addition of a ring control section that regulates and monitors all cryogenic signals in the RHIC tunnel. The system is fully automated, which can run without the continuous presence of operators.

  16. Parity splitting and E1/E2 branching in the alternating parity band of {sup 240}Pu from two-center octupole wave functions using supersymmetric quantum mechanics

    SciTech Connect

    Jolos, R. V.; Brentano, P. von

    2011-08-15

    An interpretation is suggested of the recently published experimental data on the alternating parity bands in {sup 240}Pu. The interpretation is based on the assumption that the main role in the description of the properties of the alternating parity bands plays the octupole mode which preserves the axial symmetry. The mathematical technique of the supersymmetric quantum mechanics is used for the realization of the model with the two-center octupole wave functions. A good description of the parity splitting and of the ratio of the dipole and quadrupole transitional moments is obtained for the first two bands.

  17. Some aspects of the layout and optimization for the cryogenic supply of superconducting linacs

    NASA Astrophysics Data System (ADS)

    Petersen, Bernd

    2006-02-01

    The primary power consumption of large linear accelerators can be significantly lowered by means of superconducting RF technologies. Nevertheless, superconducting RF cavities dissipate energy at low temperatures, and large cryogenic plants have to be operated for the cryogenic supply. In particular, cryogenic plants for future superconducting Energy Recovery Linacs (ERLs) will require primary power in the order of some mega watts. Because of the fundamental laws of thermodynamics, the efficiencies of the cryogenic plants decrease with decreasing operation temperature. At the same time, the dynamic heat losses of high- Q0 superconducting cavities decrease strongly with temperature. In order to minimize the primary power consumption at stable operating conditions of the cavities, the cryogenic operating conditions, and in particular the operation temperature, have to be optimized. With the focus on helium II cooling, some aspects of cryogenic efficiencies at low temperatures and the consequences for the layout of cryogenic systems are discussed. As an example, options for the cryogenic layout of the European XFEL-Linac including some ERL upgrade options are presented.

  18. Latest developments in cryogenic safety

    NASA Astrophysics Data System (ADS)

    Webster, T. J.

    1983-03-01

    The Cryogenic Safety Manual, sponsored by the British Cryogenics Council, was published over 10 years ago. A new updated version is now available. Some general aspects of cryogenic safety are highlighted, and attention is drawn to some of the more unusual hazardous situations. An awareness of the physical properties of the cryogenic fluids being dealt with is important in directing attention to hazardous situations which may arise. Because of this, the more important properties of the cryogenic fluids are given, such as molecular weight, boiling point and freezing point. From these properties, hazardous situations can be deduced. There are hidden dangers that are not always easy to spot. Some of the unexpected hazards, most of which have led to deaths, are: asphyxiation (anoxia), frost bites and hypothermia, explosions, and combustion. The aim of this publication is to help bring about increased safety in the production and use of cryogenic products through a deeper appreciation of the scientific, technological and administrative steps which must be made if accidents, some fatal, are to be voided in the future.

  19. Latest developments in cryogenic safety

    NASA Technical Reports Server (NTRS)

    Webster, T. J.

    1983-01-01

    The Cryogenic Safety Manual, sponsored by the British Cryogenics Council, was published over 10 years ago. A new updated version is now available. Some general aspects of cryogenic safety are highlighted, and attention is drawn to some of the more unusual hazardous situations. An awareness of the physical properties of the cryogenic fluids being dealt with is important in directing attention to hazardous situations which may arise. Because of this, the more important properties of the cryogenic fluids are given, such as molecular weight, boiling point and freezing point. From these properties, hazardous situations can be deduced. There are hidden dangers that are not always easy to spot. Some of the unexpected hazards, most of which have led to deaths, are: asphyxiation (anoxia), frost bites and hypothermia, explosions, and combustion. The aim of this publication is to help bring about increased safety in the production and use of cryogenic products through a deeper appreciation of the scientific, technological and administrative steps which must be made if accidents, some fatal, are to be voided in the future.

  20. Evolvable Cryogenics (ECRYO) Pressure Transducer Calibration Test

    NASA Technical Reports Server (NTRS)

    Diaz, Carlos E., Jr.

    2015-01-01

    This paper provides a summary of the findings of recent activities conducted by Marshall Space Flight Center's (MSFC) In-Space Propulsion Branch and MSFC's Metrology and Calibration Lab to assess the performance of current "state of the art" pressure transducers for use in long duration storage and transfer of cryogenic propellants. A brief historical narrative in this paper describes the Evolvable Cryogenics program and the relevance of these activities to the program. This paper also provides a review of three separate test activities performed throughout this effort, including: (1) the calibration of several pressure transducer designs in a liquid nitrogen cryogenic environmental chamber, (2) the calibration of a pressure transducer in a liquid helium Dewar, and (3) the calibration of several pressure transducers at temperatures ranging from 20 to 70 degrees Kelvin (K) using a "cryostat" environmental chamber. These three separate test activities allowed for study of the sensors along a temperature range from 4 to 300 K. The combined data shows that both the slope and intercept of the sensor's calibration curve vary as a function of temperature. This homogeneous function is contrary to the linearly decreasing relationship assumed at the start of this investigation. Consequently, the data demonstrates the need for lookup tables to change the slope and intercept used by any data acquisition system. This ultimately would allow for more accurate pressure measurements at the desired temperature range. This paper concludes with a review of a request for information (RFI) survey conducted amongst different suppliers to determine the availability of current "state of the art" flight-qualified pressure transducers. The survey identifies requirements that are most difficult for the suppliers to meet, most notably the capability to validate the sensor's performance at temperatures below 70 K.

  1. Cryogenic Neutron Spectrometer Development

    SciTech Connect

    Niedermayr, T; Hau, I D; Friedrich, S; Burger, A; Roy, U N; Bell, Z W

    2006-03-08

    Cryogenic microcalorimeter detectors operating at temperatures around {approx}0.1 K have been developed for the last two decades, driven mostly by the need for ultra-high energy resolution (<0.1%) in X-ray astrophysics and dark matter searches [1]. The Advanced Detector Group at Lawrence Livermore National Laboratory has developed different cryogenic detector technologies for applications ranging from X-ray astrophysics to nuclear science and non-proliferation. In particular, we have adapted cryogenic detector technologies for ultra-high energy resolution gamma-spectroscopy [2] and, more recently, fast-neutron spectroscopy [3]. Microcalorimeters are essentially ultra-sensitive thermometers that measure the energy of the radiation from the increase in temperature upon absorption. They consist of a sensitive superconducting thermometer operated at the transition between its superconducting and its normal state, where its resistance changes very rapidly with temperature such that even the minute energies deposited by single radiation quanta are sufficient to be detectable with high precision. The energy resolution of microcalorimeters is fundamentally limited by thermal fluctuations to {Delta}E{sub FWHM} {approx} 2.355 (k{sub B}T{sup 2}C{sub abs}){sup 1/2}, and thus allows an energy below 1 keV for neutron spectrometers for an operating temperature of T {approx} 0.1 K . The {Delta}E{sub FWHM} does not depend on the energy of the incident photon or particle. This expression is equivalent to the familiar (F{var_epsilon}E{sub {gamma}}){sup 1/2} considering that an absorber at temperature T contains a total energy C{sub abs}T, and the associated fluctuation are due to variations in uncorrelated (F=1) phonons ({var_epsilon} = k{sub B}T) dominated by the background energy C{sub abs}T >> E{gamma}. The rationale behind developing a cryogenic neutron spectrometer is the very high energy resolution combined with the high efficiency. Additionally, the response function is simple

  2. Cryogenic Permanent Magnet Undulators

    SciTech Connect

    Chavanne, J.; Lebec, G.; Penel, C.; Revol, F.; Kitegi, C.

    2010-06-23

    For an in-vacuum undulator operated at small gaps the permanent magnet material needs to be highly resistant to possible electron beam exposure. At room temperature, one generally uses Sm{sub 2}Co{sub 17} or high coercivity NdFeB magnets at the expense of a limited field performance. In a cryogenic permanent magnet undulator (CPMU), at a temperature of around 150 K, any NdFeB grade reveals a coercivity large enough to be radiation resistant. In particular, very high remanence NdFeB material can be used to build undulators with enhanced field and X-ray brilliance at high photon energy provided that the pre-baking of the undulator above 100 deg. C can be eliminated. The ESRF has developed a full scale 2 m long CPMU with a period of 18 mm. This prototype has been in operation on the ID6 test beamline since January 2008. A significant effort was put into the characterization of NdFeB material at low temperature, the development of dedicated magnetic measurement systems and cooling methods. The measured heat budget with beam is found to be larger than expected without compromising the smooth operation of the device. Leading on from this first experience, new CPMUs are currently being considered for the upgrade of the ESRF.

  3. Cryogenic Electric Motor Tested

    NASA Technical Reports Server (NTRS)

    Brown, Gerald V.

    2004-01-01

    Technology for pollution-free "electric flight" is being evaluated in a number of NASA Glenn Research Center programs. One approach is to drive propulsive fans or propellers with electric motors powered by fuel cells running on hydrogen. For large transport aircraft, conventional electric motors are far too heavy to be feasible. However, since hydrogen fuel would almost surely be carried as liquid, a propulsive electric motor could be cooled to near liquid hydrogen temperature (-423 F) by using the fuel for cooling before it goes to the fuel cells. Motor windings could be either superconducting or high purity normal copper or aluminum. The electrical resistance of pure metals can drop to 1/100th or less of their room-temperature resistance at liquid hydrogen temperature. In either case, super or normal, much higher current density is possible in motor windings. This leads to more compact motors that are projected to produce 20 hp/lb or more in large sizes, in comparison to on the order of 2 hp/lb for large conventional motors. High power density is the major goal. To support cryogenic motor development, we have designed and built in-house a small motor (7-in. outside diameter) for operation in liquid nitrogen.

  4. Dual Cryogenic Capacitive Density Sensor

    NASA Technical Reports Server (NTRS)

    Youngquist, Robert; Mata, Carlos; Vokrot, Peter; Cox, Robert

    2009-01-01

    A dual cryogenic capacitive density sensor has been developed. The device contains capacitive sensors that monitor two-phase cryogenic flow density to within 1% accuracy, which, if temperature were known, could be used to determine the ratio of liquid to gas in the line. Two of these density sensors, located a known distance apart, comprise the sensor, providing some information on the velocity of the flow. This sensor was constructed as a proposed mass flowmeter with high data acquisition rates. Without moving parts, this device is capable of detecting the density change within a two-phase cryogenic flow more than 100 times a second. Detection is enabled by a series of two sets of five parallel plates with stainless steel, cryogenically rated tubing. The parallel plates form the two capacitive sensors, which are measured by electrically isolated digital electronics. These capacitors monitor the dielectric of the flow essentially the density of the flow and can be used to determine (along with temperature) the ratio of cryogenic liquid to gas. Combining this information with the velocity of the flow can, with care, be used to approximate the total two-phase mass flow. The sensor can be operated at moderately high pressures and can be lowered into a cryogenic bath. The electronics have been substantially improved over the older sensors, incorporating a better microprocessor, elaborate ground loop protection and noise limiting circuitry, and reduced temperature sensitivity. At the time of this writing, this design has been bench tested at room temperature, but actual cryogenic tests are pending

  5. Collapsible Cryogenic Storage Vessel Project

    NASA Technical Reports Server (NTRS)

    Fleming, David C.

    2002-01-01

    Collapsible cryogenic storage vessels may be useful for future space exploration missions by providing long-term storage capability using a lightweight system that can be compactly packaged for launch. Previous development efforts have identified an 'inflatable' concept as most promising. In the inflatable tank concept, the cryogen is contained within a flexible pressure wall comprised of a flexible bladder to contain the cryogen and a fabric reinforcement layer for structural strength. A flexible, high-performance insulation jacket surrounds the vessel. The weight of the tank and the cryogen is supported by rigid support structures. This design concept is developed through physical testing of a scaled pressure wall, and through development of tests for a flexible Layered Composite Insulation (LCI) insulation jacket. A demonstration pressure wall is fabricated using Spectra fabric for reinforcement, and burst tested under noncryogenic conditions. An insulation test specimens is prepared to demonstrate the effectiveness of the insulation when subject to folding effects, and to examine the effect of compression of the insulation under compressive loading to simulate the pressure effect in a nonrigid insulation blanket under the action atmospheric pressure, such as would be seen in application on the surface of Mars. Although pressure testing did not meet the design goals, the concept shows promise for the design. The testing program provides direction for future development of the collapsible cryogenic vessel concept.

  6. Cryogenic Technology for Superconducting Accelerators

    NASA Astrophysics Data System (ADS)

    Hosoyama, Kenji

    2012-01-01

    Superconducting devices such as magnets and cavities are key components in the accelerator field for increasing the beam energy and intensity, and at the same time making the system compact and saving on power consumption in operation. An effective cryogenic system is required to cool and keep the superconducting devices in the superconducting state stably and economically. The helium refrigeration system for application to accelerators will be discussed in this review article. The concept of two cooling modes -- the liquefier and refrigerator modes -- will be discussed in detail because of its importance for realizing efficient cooling and stable operation of the system. As an example of the practical cryogenic system, the TRISTAN cryogenic system of KEK Laboratory will be treated in detail and the main components of the cryogenic system, including the high-performance multichannel transfer line and liquid nitrogen circulation system at 80K, will also be discussed. In addition, we will discuss the operation of the cryogenic system, including the quench control and safety of the system. The satellite refrigeration system will be discussed because of its potential for wide application in medium-size accelerators and in industry.

  7. Overflow sensor for cryogenic-fluid vessels

    NASA Technical Reports Server (NTRS)

    Tener, W. M.

    1972-01-01

    Overflow sensor for cryogenic fluid vessels has been designed by winding electrical resistance element on porous tubular coil form. Form is positioned in overflow vent of cryogenic fluid vessel where it can differentiate vapor from liquid at same temperature.

  8. Other cryogenic wind tunnel projects

    NASA Technical Reports Server (NTRS)

    Kilgore, Robert A.

    1989-01-01

    The first cryogenic tunnel was built in 1972. Since then, many cryogenic wind-tunnel projects were started at aeronautical research centers around the world. Some of the more significant of these projects are described which are not covered by other lecturers at this Special Course. Described are cryogenic wind-tunnel projects in five countries: China (Chinese Aeronautical Research and Development Center); England (College of Aeronautics at Cranfield, and Royal Aerospace Establishment-Bedford); Japan (National Aerospace Laboratory, University of Tsukuba, and National Defense Academy); United States (Douglas Aircraft Co., University of Illinois at Urbana-Champaign and NASA Langley); and U.S.S.R. (Central Aero-Hydronamics Institute (TsAGI), Institute of Theoretical and Applied Mechanics (ITAM), and Physical-Mechanical Institute at Kharkov (PMI-K).

  9. Silicon photomultiplier properties at cryogenic temperatures

    NASA Astrophysics Data System (ADS)

    Biroth, M.; Achenbach, P.; Downie, E.; Thomas, A.

    2015-07-01

    The properties of different types of silicon photomultipliers (SiPMs) were studied at cryogenic temperatures. In liquid nitrogen at 77 K, problems with quenching in Hamamatsu SiPMs and with the protective epoxy layer, covering Zecotek SiPMs, were observed. Tests with one Zecotek SiPM were successful after removal of the epoxy layer. In liquid helium at 4 K, fast signals with pulse lengths shorter than 50 ns were observed, the dark count rate was below 10 Hz and no after-pulses were detected. The gain, as a function of over-voltage, was comparable to room temperature. The SiPM's response to photons was found to be linear with intensity for low light levels and single-photon detection was possible at 4 K.

  10. Gauging Systems Monitor Cryogenic Liquids

    NASA Technical Reports Server (NTRS)

    2009-01-01

    Rocket fuel needs to stay cool - super cool, in fact. The ability to store gas propellants like liquid hydrogen and oxygen at cryogenic temperatures (below -243 F) is crucial for space missions in order to reduce their volumes and allow their storage in smaller (and therefore, less costly) tanks. The Agency has used these cryogenic fluids for vehicle propellants, reactants, and life support systems since 1962 with the Centaur upper stage rocket, which was powered with liquid oxygen and liquid hydrogen. During proposed long-duration missions, super-cooled fluids will also be used in space power systems, spaceports, and lunar habitation systems. In the next generation of launch vehicles, gaseous propellants will be cooled to and stored for extended periods at even colder temperatures than currently employed via a process called densification. Densification sub-cools liquids to temperatures even closer to absolute zero (-459 F), increasing the fluid s density and shrinking its volume beyond common cryogenics. Sub-cooling cryogenic liquid hydrogen, for instance, from 20 K (-423 F) to 15 K (-432.4 F) reduces its mass by 10 percent. These densified liquid gases can provide more cost savings from reduced payload volume. In order to benefit from this cost savings, the Agency is working with private industry to prevent evaporation, leakage, and other inadvertent loss of liquids and gases in payloads - requiring new cryogenic systems to prevent 98 percent (or more) of boil-off loss. Boil-off occurs when cryogenic or densified liquids evaporate, and is a concern during launch pad holds. Accurate sensing of propellants aboard space vehicles is also critical for proper engine shutdown and re-ignition after launch, and zero boil-off fuel systems are also in development for the Altair lunar lander.

  11. Superfluid helium cryogenic systems for superconducting RF cavities at KEK

    SciTech Connect

    Nakai, H.; Hara, K.; Honma, T.; Hosoyama, K.; Kojima, Y.; Nakanishi, K.; Kanekiyo, T.; Morita, S.

    2014-01-29

    Recent accelerator projects at KEK, such as the Superconducting RF Test Facility (STF) for R and D of the International Linear Collider (ILC) project and the compact Energy Recovery Linac (cERL), employ superconducting RF cavities made of pure niobium, which can generate high gradient acceleration field. Since the operation temperature of these cavities is selected to be 2 K, we have developed two 2 K superfluid helium cryogenic systems for stable operation of superconducting RF cavities for each of STF and cERL. These two 2 K superfluid helium cryogenic systems are identical in principle. Since the operation mode of the cavities is different for STF and cERL, i.e. the pulse mode for STF and the continuous wave mode for cERL, the heat loads from the cavities are quite different. The 2 K superfluid helium cryogenic systems mainly consists of ordinary helium liquefiers/refrigerators, 2 K refrigerator cold boxes, helium gas pumping systems and high-performance transfer lines. The 2 K refrigerators and the high-performance transfer lines are designed by KEK. Some superconducting RF cavity cryomodules have been already connected to the 2 K superfluid helium cryogenic systems for STF and cERL respectively, and cooled down to 2 K successfully.

  12. Cryogenic thermal diode heat pipes

    NASA Technical Reports Server (NTRS)

    Alario, J.

    1979-01-01

    The development of spiral artery cryogenic thermal diode heat pipes was continued. Ethane was the working fluid and stainless steel the heat pipe material in all cases. The major tasks included: (1) building a liquid blockage (blocking orifice) thermal diode suitable for the HEPP space flight experiment; (2) building a liquid trap thermal diode engineering model; (3) retesting the original liquid blockage engineering model, and (4) investigating the startup dynamics of artery cryogenic thermal diodes. An experimental investigation was also conducted into the wetting characteristics of ethane/stainless steel systems using a specially constructed chamber that permitted in situ observations.

  13. A piezoelectric cryogenic heat switch

    NASA Astrophysics Data System (ADS)

    Jahromi, Amir E.; Sullivan, Dan F.

    2014-06-01

    We have measured the thermal conductance of a mechanical heat switch actuated by a piezoelectric positioner, the PZHS (PieZo electric Heat Switch), at cryogenic temperatures. The thermal conductance of the PZHS was measured between 4 K and 10 K, and on/off conductance ratios of about 100-200 at lowest and highest measures temperature were achieved when the positioner applied its maximum force of 8 N, respectively. We discuss the advantages of using this system in cryogenic applications, and estimate the ultimate performance of an ideal PZHS.

  14. Optical Cryogenic Tank Level Sensor

    NASA Technical Reports Server (NTRS)

    Duffell, Amanda

    2005-01-01

    Cryogenic fluids play an important role in space transportation. Liquid oxygen and hydrogen are vital fuel components for liquid rocket engines. It is also difficult to accurately measure the liquid level in the cryogenic tanks containing the liquids. The current methods use thermocouple rakes, floats, or sonic meters to measure tank level. Thermocouples have problems examining the boundary between the boiling liquid and the gas inside the tanks. They are also slow to respond to temperature changes. Sonic meters need to be mounted inside the tank, but still above the liquid level. This causes problems for full tanks, or tanks that are being rotated to lie on their side.

  15. A piezoelectric cryogenic heat switch.

    PubMed

    Jahromi, Amir E; Sullivan, Dan F

    2014-06-01

    We have measured the thermal conductance of a mechanical heat switch actuated by a piezoelectric positioner, the PZHS (PieZo electric Heat Switch), at cryogenic temperatures. The thermal conductance of the PZHS was measured between 4 K and 10 K, and on/off conductance ratios of about 100-200 at lowest and highest measures temperature were achieved when the positioner applied its maximum force of 8 N, respectively. We discuss the advantages of using this system in cryogenic applications, and estimate the ultimate performance of an ideal PZHS. PMID:24985863

  16. First observation of excited states in {sup 137}Te and the extent of octupole instability in the lanthanides

    SciTech Connect

    Urban, W.; Korgul, A.; Rzaca-Urban, T.; Schulz, N.; Bentaleb, M.; Lubkiewicz, E.; Durell, J. L.; Leddy, M. J.; Jones, M. A.; Phillips, W. R.

    2000-04-01

    Excited states in {sup 137}Te, populated in spontaneous fission of {sup 248}Cm, were studied by means of prompt-{gamma} spectroscopy, using the EUROGAM2 multidetector array. This is the first observation of excited states in {sup 137}Te. The yrast excitations of {sup 137}Te are due to the three valence neutrons, occupying the {nu}f{sub 7/2} and {nu}h{sub 9/2} orbitals, similarly as observed in its heavier N=85 isotones. Systematic comparison of excited levels in the N=85 isotones shows inconsistencies in spin and parity assignments in {sup 139}Xe and {sup 141}Ba nuclei. The new data for {sup 137}Te do not confirm earlier suggestions that octupole correlations increase in the N=85 isotones, close to the Z=50 closed shell. (c) 2000 The American Physical Society.

  17. Superdeformed nuclei: Shells-vs-liquid drop, pairing-vs-thermal excitations, triaxial-vs-octupole shapes, super-superdeformation

    SciTech Connect

    Dudek, J.

    1987-01-01

    Mechanisms influencing the behavior of superdeformed nuclei are studied using several well established nuclear structure techniques. In particular: pairing, thermal excitation, shell and liquid-drop mechanisms are considered. The effects of quadrupole and hexadecapole (both axial and non-axial), and octupole deformation degrees of freedom are studied. Most of the results are illustrated using the case of /sup 152/Dy nucleus in which a superdeformed band extending up to I approx. 60 h-bar has been found in experiment. Some comparisons between /sup 152/Dy and the nuclei in the neighborhood are given. Calculations show that pairing ''de-aligns'' typically 6 to 8 units of angular momentum, as compared to the corresponding rigid rotation. This takes place for spins extending up to the highest limit, and thus diminishes the effective moments of inertia. Predicted octupole shape susceptibility is extremely large, significantly stronger than the susceptibilities known in the ground-states of many Actinide nuclei. Consequences of this result for the near-constancy of the dynamical moments of inertia are pointed out. Nuclear level densities calculated in function of spin, excitation energy and deformation explain the ''unusual'' side feeding pattern of the /sup 152/Dy superdeformed states. Predictions of super-superdeformed nuclear states (axis ratio varying between 2:1 and 3:1 or more) are given and exemplified for Erbium nuclei. Finally, the problem of superdeformation stability and the influence of increased collective inertia on a barrier penetration are examined. An analytical expression for the effective inertia parameter is obtained and its derivation outlined. 35 refs., 9 figs.

  18. gamma-ray spectroscopic study of calcium-48,49 and scandium-50 focusing on low lying octupole vibration excitations

    NASA Astrophysics Data System (ADS)

    McPherson, David M.

    An inverse kinematic proton scattering experiment was performed at the National Superconducting Cyclotron Laboratory (NSCL) using the GRETINA-S800 detector system in conjunction with the Ursinus College liquid hydrogen target. gamma-ray yields from the experiment were determined using geant4 simulations, generating state population cross sections. These cross sections were used to extract the delta_3 deformation length for the low-lying octupole vibration excitations in Ca-48,49 using the coupled channels analysis code fresco. Particle-core coupling in Ca-49 was studied in comparison to Ca-48 through determination of the neutron and proton deformation lengths. The total inverse kinematic proton scattering deformation lengths were evaluated for the low-lying octupole vibration excitations in Ca-48,49 to be delta_3(Ca-48, 3. -_1) = 1.0(2)fm,delta_3(Ca-49, 9/2. +_1) = 1.2(1)fm, delta_3 (Ca-49, 9/2. +_1) = 1.5(2)fm, delta_3(Ca-49,5/2. +_1) = 1.1(1)fm. Proton and neutron deformation lengths for two of theseoctupole states were also determined to be delta_p(Ca-48, 3. -_1) = 0.9(1)fm,delta_p (Ca-49, 9/2. +_1) = 1.0(1)fm, delta_n(Ca-48, 3. -_1) = 1.1(3)fm, anddelta_n(Ca-49, 9/2. +_1) = 1.3(3)fm. Additionally, the ratios of the neutronto proton transition matrix elements were also determined for these two states to be M_n/M_p(Ca-48, 3. -_1) = 1.7(6) and M_n/M_p(Ca-49, 9/2. +_1) = 2.0(5).Statistically, the derived values for these two nuclei are nearly identical.

  19. Level Sensor for Cryogenic Fluids

    NASA Technical Reports Server (NTRS)

    Simmons, N. E.; Schroff, R. A.

    1983-01-01

    Hot wire sensor combined with voltage-comparator circuit monitors liquid level in cryogenic-fluid storage tanks. Sensor circuit adaptable to different liquids and sensors. Constant-current source drives current through sensing probe and fixed resistor. Voltage comparator circuits interpret voltage drops to tell whether probe is immersed in liquid and is current in probe.

  20. Background reduction in cryogenic detectors

    SciTech Connect

    Bauer, Daniel A.; /Fermilab

    2005-04-01

    This paper discusses the background reduction and rejection strategy of the Cryogenic Dark Matter Search (CDMS) experiment. Recent measurements of background levels from CDMS II at Soudan are presented, along with estimates for future improvements in sensitivity expected for a proposed SuperCDMS experiment at SNOLAB.

  1. Foam shell cryogenic ICF target

    DOEpatents

    Darling, Dale H.

    1987-01-01

    A uniform cryogenic layer of DT fuel is maintained in a fusion target having a low density, small pore size, low Z rigid foam shell saturated with liquid DT fuel. Capillary action prevents gravitational slumping of the fuel layer. The saturated shell may be cooled to produce a solid fuel layer.

  2. Operation of large cryogenic systems

    SciTech Connect

    Rode, C.H.; Ferry, B.; Fowler, W.B.; Makara, J.; Peterson, T.; Theilacker, J.; Walker, R.

    1985-06-01

    This report is based on the past 12 years of experiments on R and D and operation of the 27 kW Fermilab Tevatron Cryogenic System. In general the comments are applicable for all helium plants larger than 1000W (400 l/hr) and non mass-produced nitrogen plants larger than 50 tons per day. 14 refs., 3 figs., 1 tab.

  3. Filling an Unvented Cryogenic Tank

    NASA Technical Reports Server (NTRS)

    Beck, Phillip; Willen, Gary S.

    1987-01-01

    Slow-cooling technique enables tank lacking top vent to be filled with cryogenic liquid. New technique: pressure buildup prevented through condensation of accumulating gas resulting in condensate being added to bulk liquid. Filling method developed for vibration test on vacuum-insulated spherical tank containing liquid hydrogen.

  4. Survey of cryogenic semiconductor devices

    SciTech Connect

    Talarico, L.J.; McKeever, J.W.

    1996-04-01

    Improved reliability and electronic performance can be achieved in a system operated at cryogenic temperatures because of the reduction in mechanical insult and in disruptive effects of thermal energy on electronic devices. Continuing discoveries of new superconductors with ever increasing values of T{sub c} above that of liquid nitrogen temperature (LNT) have provided incentive for developing semiconductor electronic systems that may also operate in the superconductor`s liquid nitrogen bath. Because of the interest in high-temperature superconductor (HTS) devices, liquid nitrogen is the cryogen of choice and LNT is the temperature on which this review is focused. The purpose of this survey is to locate and assemble published information comparing the room temperature (298 K), performance of commercially available conventional and hybrid semiconductor device with their performance at LNT (77K), to help establish their candidacy as cryogenic electronic devices specifically for use at LNT. The approach to gathering information for this survey included the following activities. Periodicals and proceedings were searched for information on the behavior of semiconductor devices at LNT. Telephone calls were made to representatives of semiconductor industries, to semiconductor subcontractors, to university faculty members prominent for their research in the area of cryogenic semiconductors, and to representatives of the National Aeronautics and Space Administration (NASA) and NASA subcontractors. The sources and contacts are listed with their responses in the introduction, and a list of references appears at the end of the survey.

  5. Ames Research Center cryogenics program

    NASA Technical Reports Server (NTRS)

    Kittel, Peter

    1987-01-01

    Viewgraphs describe the Ames Research Center's cryogenics program. Diagrams are given of a fluid management system, a centrifugal pump, a flow meter, a liquid helium test facility, an extra-vehicular activity coupler concept, a dewar support with passive orbital disconnect, a pulse tube refrigerator, a dilution refrigerator, and an adiabatic demagnetization cooler.

  6. Dust Charge in Cryogenic Environment

    SciTech Connect

    Kubota, J.; Kojima, C.; Sekine, W.; Ishihara, O.

    2008-09-07

    Dust charges in a complex helium gas plasma, surrounded by cryogenic liquid, are studied experimentally. The charge is determined by frequency and equilibrium position of damped dust oscillation proposed by Tomme et al.(2000) and is found to decrease with ion temperature of the complex plasma.

  7. Status Of Sorption Cryogenic Refrigeration

    NASA Technical Reports Server (NTRS)

    Jones, Jack A.

    1988-01-01

    Report reviews sorption refrigeration. Developed for cooling infrared detectors, cryogenic research, and other advanced applications, sorption refrigerators have few moving parts, little vibration, and lifetimes of 10 years or more. Describes types of sorption stages, multistage and hybrid refrigeration systems, power requirements, cooling capacities, and advantages and disadvantages of various stages and systems.

  8. Fast response cryogen level sensor

    NASA Technical Reports Server (NTRS)

    Fitzpatrick, J. B.; Maier, L. C.

    1981-01-01

    Liquid level in cryogenic tank or pipe, or amount of gas trapped in pipeline flow, is monitored electronically by cylindrical capacitive sensor. Changes in liquid level between concentric tubes of capacitor change its impedance, varying current in drive circuit. Since it is oriented parallel to direction of liquid flow, sensor presents little resistance to moving fluid.

  9. Cryogenic MMIC Low Noise Amplifiers

    NASA Technical Reports Server (NTRS)

    Weinreb, S.; Gaier, T.; Fernandez, J.; Erickson, N.; Wielgus, J.

    2000-01-01

    Monolithic (MMIC) and discrete transistor (MIC) low noise amplifiers are compared on the basis of performance, cost, and reliability. The need for cryogenic LNA's for future large microwave arrays for radio astronomy is briefly discussed and data is presented on a prototype LNA for the 1 to 10 GZH range along with a very wideband LNA for the 1 to 60 GHz range.

  10. A Magnetically Coupled Cryogenic Pump

    NASA Technical Reports Server (NTRS)

    Hatfield, Walter; Jumper, Kevin

    2011-01-01

    Historically, cryogenic pumps used for propellant loading at Kennedy Space Center (KSC) and other NASA Centers have a bellows mechanical seal and oil bath ball bearings, both of which can be problematic and require high maintenance. Because of the extremely low temperatures, the mechanical seals are made of special materials and design, have wearing surfaces, are subject to improper installation, and commonly are a potential leak path. The ball bearings are non-precision bearings [ABEC-1 (Annular Bearing Engineering Council)] and are lubricated using LOX compatible oil. This oil is compatible with the propellant to prevent explosions, but does not have good lubricating properties. Due to the poor lubricity, it has been a goal of the KSC cryogenics community for the last 15 years to develop a magnetically coupled pump, which would eliminate these two potential issues. A number of projects have been attempted, but none of the pumps was a success. An off-the-shelf magnetically coupled pump (typically used with corrosive fluids) was procured that has been used for hypergolic service at KSC. The KSC Cryogenics Test Lab (CTL) operated the pump in cryogenic LN2 as received to determine a baseline for modifications required. The pump bushing, bearings, and thrust rings failed, and the pump would not flow liquid (this is a typical failure mode that was experienced in the previous attempts). Using the knowledge gained over the years designing and building cryogenic pumps, the CTL determined alternative materials that would be suitable for use under the pump design conditions. The CTL procured alternative materials for the bearings (bronze, aluminum bronze, and glass filled PTFE) and machined new bearing bushings, sleeves, and thrust rings. The designed clearances among the bushings, sleeves, thrust rings, case, and case cover were altered once again using experience gained from previous cryogenic pump rebuilds and designs. The alternative material parts were assembled into