110192617
CRYOGENICS, KEY TO ADVANCED SCIENCE AND TECHNOLOGY
A method of press-connecting a coated electric wire with a press-connecting terminal, including the step of pressing an end portion of the coated electric wire into a notched slot provided in a side plate of the press-connecting terminal so as to cut a coating portion of the coated electric wire to thereby make a conductor of the coated electric wire electrically connected to the side plate of the press-connecting terminal. In such a method, before the coated electric wire is press-connected with the press-connecting terminal, the coating portion of the coated electric wire is heated and softened so that the force necessary for pressing the coated electric wire into the notched slot is reduced to be not larger than a predetermined value.
118122719
DESIGN, TEST AND PERFORMANCE OF THE LIQUID HELIUM CRYOSTATS FOR THE LEP SUPERCONDUCTING QUADRUPOLE MAGNETS
The experimental areas of LEP, the high-energy electron-positron collider presently under construction at CERN, will be equipped with eight superconducting quadrupole magnets, housed in liquid helium cryostats embedded in the complex detector set-ups. To comply with transverse space restrictions, the 2.5 m-long slender cryostats feature a 130 mm diameter warm bore and a horizontally-oriented service funnel at one end, equipped with 2000 A current leads. The cryostats have been designed by CERN, manufactured and assembled by industry, and tested in the laboratory. Besides design principles and constructional features, results of tests and comparative performance data are presented.
116929466
The superfluid helium model cryoloop for the CERN Large Hadron Collider (LHC)
The high-field superconducting magnets of the CERN Large Hadron Collider (LHC) will operate in static pressurized helium II at a maximum temperature of 1.9 K, irrespective of their position around the 26.7 km circumference of the machine ring. Their static and dynamic heat loads will be transported by conduction in the pressurized helium II, to a heat exchanger tube threading its way along the magnet string, in which flowing saturated helium II absorbs the heat in quasi-isothermal conditions. Following promising results obtained with heated flow tests on two-phase helium II, a full-scale 20 m-long thermohydraulic model of a LHC cryoloop was designed, built and operated, addressing key issues such as flow stability, steady-state heat transfer, transient response to varying loads, control strategies, and influence of slope. We present the results obtained and show that they validate the basic design choices of the proposed LHC cryogenic system.
55204249
A Cryogenic Axial-Centrifugal Compressor For Superfluid Helium Refrigeration
CERN's new project, the Large Hadron Collider (LHC), will use superfluid helium as coolant for its high-field superconducting magnets and therefore require large capacity refrigeration at 1.8 K. This may only be achieved by subatmospheric compression of gaseous helium at cryogenic temperature. To stimulate development of this technology, CERN has procured from industry prototype Cold Compressor Units (CCU). This unit is based on a cryogenic axial-centrifugal compressor, running on ceramic ball bearings and driven by a variable-frequency electrical motor operating under low-pressure helium at ambient temperature. The machine has been commissioned and is now in operation. After describing basic constructional features of the compressor, we report on measured performance.
122695581
TOWARDS COST-TO-PERFORMANCE OPTIMISATION OF LARGE SUPERFLUID HELIUM REFRIGERATION SYSTEMS
The field range of superconducting devices may be extended by lowering their operating temperature, using superfluid helium refrigeration systems which have to deliver working pressures down to 1.6 kPa. The corresponding pressure ratio can be produced by integral cold compression or using a combination of cold compressors in series together with "warm" compressors at room temperature. The optimisation of such a system depends on the number, arrangement and characteristics of cold and warm machines as well as on the operating scenario and turndown capability. The aim of this paper is to compare relative investment and operating costs of different superfluid helium cryogenic systems, with the aim of optimising their cost-to-performance ratio within the constraints of their operating scenario.
133673972
Investigation and qualification of thermal insulation systems between 80-K and 4.2-K
54039880
Using workstation GUIs in HEP, X-Windows, Motif and the Nirvana project
We present four small, high quality, Motif based tools for high energy physicists and discuss some of the less obvious work that is necessary to fully take advantage of graphical user interfaces (GUIs). Histo-Scope and NPlot are interactive data display programs. Histo-Scope is for viewing data as it is collected in running analysis or data acquisition programs, NPlot, for plotting data from text files. Visajet is an interface for the ISAJET event simulation program. It gives users a fast way to configure ISAJET and displays ISAJET events in a three dimensional phase space display that users can rotate and manipulate with the mouse. NEdit is a GUI style plain text editor.
122472626
Recent results from Fermilab E687 on charm spectroscopy
Recent analyses of charm spectroscopy from Fermilab fixed target experiment 687 [1] are summarized. Emphasis is placed on the phenomenology of Cabibbo suppression in the meson sector. Such transitions have been observed in the semileptonic modes and hadronic modes. While the former transitions give us an opportunity to observe the weak current and the CKM matrix, a systematic comparison of the latter transitions allow us to study strong interaction effects, and possibly, light quark spectroscopy.
125706131
The Single Field Flip Cooling Channel for a Neutrino Factory
59802398
Open inventor and virtual reality at Fermilab
We discuss our experiences with Open Inventor and with basic tools and techniques of Virtual Reality, including some preliminary results from an immersive system.
120522308
High energy cosmic muons and the calibration of the L3 electromagnetic calorimeter
Abstract A method to calibrate the L3 electromagnetic calorimeter with cosmic muons has been tested on a matrix of 100 tapered BGO crystals. Calibration constants in the energy range of 20–30 MeV were measured at the 2% level collecting about 200 muons per crystal. The results are in agreement with the calibration constant determined using a 10 GeV electron beam.