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Design Alternatives for a Free Electron Laser Facility

Description: The University of Wisconsin-Madison is continuing design efforts for a vacuum ultraviolet/X-ray Free Electron Laser facility. The design incorporates seeding the FEL to provide fully coherent photon output at energies up to {approx}1 keV. The focus of the present work is to minimize the cost of the facility while preserving its performance. To achieve this we are exploring variations in the electron beam driver for the FEL, in undulator design, and in the seeding mechanism. Design optimizations and trade-offs between the various technologies and how they affect the FEL scientific program will be presented.
Date: July 1, 2012
Creator: Jacobs, K; Bosch, R A; Eisert, D; Fisher, M V; Green, M A; Keil, R G et al.
Partner: UNT Libraries Government Documents Department

Tests of a GM Cryocooler and high Tc leads for use on the ALS superbend magnets

Description: A 1.5 W (at the second stage) Gifford McMahon (GM) cryocooler was selected for cooling the superconducting SuperBend dipoles for the Advanced Light Source (ALS) at Berkeley. A GM cryocooler is a reasonable choice if conduction cooled leads are used to provide current to the superconducting magnet. The expected parasitic heat leaks are expected to range from 0.1 to 0.5 W at 4.2 K depending on the temperature of the shield and the cold mass support intercepts. Heat flow to 4 K down the SuperBend 350 A high Tc superconducting leads is expected to vary from 0.11 to 0.35 W depending on the intercept temperature and the current in the leads. The high Tc leads are designed to carry 350 A without significant resistive heating when the upper end of the lead is at 80 K. The 1.5 W cryocooler is expected to provide 45 to 50 W of refrigeration at the first stage at 50 K. The parasitic beat load into the first stage of the cryocooler will be about 8 W. The heat flow from 300 K down the upper copper leads is expected to be around 30 W. The cryocooler and high Tc lead test will measure the penormance of the cryocooler and the high Tc leads. The heat leak down the cryocooler, when it is not operating, is also of interest.
Date: July 9, 1999
Creator: Zbasnik, J.; Green, M.A.; Hoyer, E.H.; Taylor, C.E.; Chen, J.Y. & Wang, S.T.
Partner: UNT Libraries Government Documents Department

Cryogenic Tests of the g-2 Superconducting Solenoid Magnet System

Description: The g-2 muon storage nng magnet system consists of four large superconducting solenoids that are up to 15.1 m in diameter. The g-2 superconducting solenoids and a superconducting inflector dipole will be cooled using forced two-phase helium in tubes. The forced two-phase helium cooling will be provided from the J-T circuit of a refrigerator that is capable of delivering 625 W at 4.5 K. The two-phase helium flows from the refrigerator J-T circuit through a heat exchanger in a storage dewar that acts as a phase separator for helium returning from the magnets. The use of a heat exchanger in the storage dewar reduces the pressure drop in the magnet flow circuit, eliminates most two phase flow oscillations, and it permits the magnets to operate at variable thermal loads using the liquid in the storage dewar as a buffer. The g-2 magnet cooling system will consist of three parallel two-phase helium flow circuits that provide cooling to the following components: (1) the four large superconducting solenoids, (2) the current interconnects between the solenoids and the solenoid gas cooled electrical leads, and (3) the inflector dipole and its gas cooled electrical leads. This report describes a cryogenic test of the two 15.1 meter diameter superconducting solenoids using two-phase helium from a dewar. The report describes the cool down procedure for the 3.5 ton outer solenoid magnet system using liquid nitrogen and two-phase helium. Low current operation of the outer solenoids is discussed.
Date: July 1, 1995
Creator: Jia, L.X.; Cullen Jr., J.R.; Esper, A.J.; Meier, R.E.; Pai, C.; Snydstrup, L. et al.
Partner: UNT Libraries Government Documents Department

Refrigeration options for the Advanced Light Source Superbend Dipole Magnets

Description: The 1.9 GeV Advance Light Source (ALS) at the Lawrence Berkeley National Laboratory (LBNL) produces photons with a critical energy of about 3.1 kev at each of its thirty-six 1.3 T gradient bending magnets. It is proposed that at three locations around the ring the conventional gradient bending magnets be replaced with superconducting bending magnets with a maximum field of 5.6 T. At the point where the photons are extracted, their critical energy will be about 12 keV. In the beam lines where the SuperBend superconducting magnets are installed, the X ray brightness at 20 keV will be increased over two orders of magnitude. This report describes three different refrigeration options for cooling the three SuperBend dipoles. The cooling options include: (1) liquid helium and liquid nitrogen cryogen cooling using stored liquids, (2) a central helium refrigerator (capacity 70 to 100 W) cooling all of the SuperBend magnets, (3) a Gifford McMahon (GM) cryocooler on each of the dipoles. This paper describes the technical and economic reasons for selecting a small GM cryocooler as the method for cooling the SuperBend dipoles on the LBNL Advanced Light Source.
Date: July 9, 1999
Creator: Green, M.A.; Hoyer, E.H.; Schlueter, R.D.; Taylor, C.E.; Zbasnik, J. & Wang, S.T.
Partner: UNT Libraries Government Documents Department

Bent solenoid simulations for the muon cooling experiment

Description: The muon collider captures pions using solenoidal fields. The pion are converted to muons as they are bunched in an RF phase rotation system. Solenoids are used to focus the muons as their emitance is reduced during cooling. Bent solenoids are used to sort muons by momentum. This report describes a bent solenoid system that is part of a proposed muon cooling experiment. The superconducting solenoid described in this report consists of a straight solenoid that is 1.8 m long, a bent solenoid that is 1.0 m to 1.3 m long and a second straight solenoid that is 2.6 m long. The bent solenoid bends the muons over an angle of 57.3 degrees (1 radian). The bent solenoid has a minor coil radius (to the center of the coil) that is 0.24 m and a major radius (of the solenoid axis) of 1.0 m. The central induction along the axis is 3.0 T There is a dipole that generates an induction of 0.51 T, perpendicular to the plane of the bend, when the induction on the bent solenoid axis is 3.0 T.
Date: July 9, 1999
Creator: Green, M.A.; Eyssa, Y.M.; Kenney, S.; Miller, J.R. & Prestemon, S.
Partner: UNT Libraries Government Documents Department

Superconducting magnets for muon capture and phase rotation

Description: There are two key systems that must operate efficiently, in order for a muon collider to be a viable option for high energy physics. These systems are the muon production and collection system and the muon cooling system. Both systems require the use of high field superconducting solenoid magnets. This paper describes the supcrconducting solenoid system used for the capture and phase rotation of the pions that are produced on a target in a high intensity proton beam.
Date: July 26, 1999
Creator: Green, M.A. & Weggel, R.J.
Partner: UNT Libraries Government Documents Department

Design and Testing of a Superfluid Liquid Helium CoolingLoop

Description: This paper describes the design and preliminary testing of a cryogenic cooling loop that uses a thermomechanical pump to circulate superfluid liquid helium. The cooling loop test apparatus is designed to prove forced liquid helium flow concepts that will be used on the Astromag superconducting magnet facility.
Date: July 24, 1989
Creator: Gavin, L.M.; Green, M.A.; Levin, S.M.; Smoot, George F. & Witebsky, C.
Partner: UNT Libraries Government Documents Department

The Cryogenic System for the ASTROMAG Test Coil

Description: This paper describes an all helium, low heat leak cryogenic system for the testing of a superconducting magnet coil for the ASTROMAG particle astrophysics experiment. The superconducting coil, which is projected to have a stored magnetic energy of 4 to 7 MJ, will be cooled by pumped helium from a liquid helium storage tank using a fountain effect helium II pump. The pumping system can be used to cool the cryogenic system down as well as keep the coil cold during its superconducting operation. The integration of retractable 900 A gas-cooled electrical leads with the intermediate shields and intercepts is discussed.
Date: July 1, 1988
Creator: Green, M.A.; Levine, S.M.; Smoot, G.F. & Witebsky, C.
Partner: UNT Libraries Government Documents Department

A superconducting bending magnet system for a compact synchrotron light source

Description: High intensity, high energy X-rays for use in protein crystallography, nano-machining and medical applications, such as non invasive coronary angiography, can be produced by a 1.2 to 1.5 GeV electron storage ring compact light source with 6 to 8 tesla superconducting bending magnets. Because the bending magnets are to be superconducting, the storage ring energy can be over factor of two lower than a conventional storage ring that delivers same photon energy. The ring, which has superconducting bending magnets, is smaller in circumference and has the advantage of having fewer particles in the ring for a given x ray source intensity. The proposed storage ring is a separated function accelerator ring with six superconducting bending magnet units. Conventional quadruples and correction elements would be located between the bending magnets. Because the synchrotron radiation is generated in the bend, the superconducting bending magnets must have a warm vacuum chamber for the electron beam. Variations of a superferric magnet design have been studied for this application. This report presents a superferric H magnet design that can produce good quality magnetic field in a region that is 50 mm high by 100 mm wide. This modified superferric H magnet design has saturated iron poles but the magnetic flux is returned from one pole to the other through an unsaturated iron return path. The dipole magnet required for a compact storage ring must be physically short (380 mm long), and the field must fall off rapidly at the ends of the magnet. This report describes a preliminary design for a pair of 6.894 tesia, thirty degree bending magnets in a common vacuum vessel for use in a 1.5 GeV compact storage ring light source.
Date: July 1, 1995
Creator: Green, M.A.; Garren, A.A.; Leung, E.M.; Madura, D.D.; Cline, D.B.; Kolonko, J.J. et al.
Partner: UNT Libraries Government Documents Department

Nb{sub 3}Sn magnets for a muon collider

Description: High field dipole and quadrupole magnet designs with racetrack coils are investigated. The design option is particularly attractive for a muon collider dipole magnet using the Nb{sub 3}Sn superconductor. A conceptual design of {approximately}15 T single aperture dipole magnet is presented where the coils maintain a simple 2-d structure through the ends. The use of racetrack coils in quadrupole magnets is also discussed. It appears that the racetrack coils are less attractive for high gradient quadrupole magnets.
Date: July 1998
Creator: Gupta, R. C.; Green, M. A.; Scanlan, R. M. & Palmer, R.
Partner: UNT Libraries Government Documents Department


Description: This report describes the solenoid magnets in the front end (the section between the pion capture solenoid and the linear acceleration section) of the Level 2 study of a neutrino factory. The magnets described in the report start with the decay channel magnets that starts 18 meter downstream from the start of the pion production target. The magnet string ends with the transition solenoids that match the muon beam from the last cooling cell to the superconducting linear accelerator section. All of the magnets described in this report are solenoids. The field on axis in the solenoidal channel ranges from 1.25 T to just over 5.5 T. This report shows that the magnets in the front end of the neutrino factory are feasible.
Date: July 1, 2002
Partner: UNT Libraries Government Documents Department

Design and testing of a superfluid liquid helium cooling loop

Description: This paper describes the design and preliminary testing of a cryogenic cooling loop that uses a thermomechanical pump to circulate superfluid liquid helium. The cooling loop test apparatus is designed to prove forced liquid helium flow concepts that will be used on the Astromag superconducting magnet facility. 3 refs., 2 figs.
Date: July 1, 1989
Creator: Gavin, L.M.; Green, M.A.; Levin, S.M.; Smoot, G.F. & Witebsky, C.
Partner: UNT Libraries Government Documents Department

Floating dry cooling: a competitive alternative to evaporative cooling in a binary cycle geothermal power plant

Description: The application of the floating cooling concept to non-evaporative and evaporative atmospheric heat rejection systems was studied as a method of improving the performance of geothermal powerplants operating upon medium temperature hydrothermal resources. The LBL thermodynamic process computer code GEOTHM is used in the case study of a 50 MWe isobutane binary cycle power plant at Heber, California. It is shown that operating a fixed capacity plant in the floating cooling mode can generate significantly more electrical energy at a higher thermodynamic efficiency and reduced but bar cost for approximately the same capital investment. Floating cooling is shown to benefit a plant which is dry cooled to an even greater extent than the same plant operating with an evaporative heat rejection system. Results of the Heber case study indicate that a dry floating cooling geothermal binary cycle plant can produce energy at a bus bar cost which is competitive with the cost of energy associated with evaporatively cooled systems.
Date: July 1, 1978
Creator: Pines, H.S.; Green, M.A.; Pope, W.L. & Doyle, P.A.
Partner: UNT Libraries Government Documents Department