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Simultaneous interferometric optical-figure characterizations for two optical elements in series: Proposition of an unconventional numerical integration scheme

Description: The article proposes a scheme to break a catch-22 loop in an optical-figure/wavefont measurement. For instance, to measure the tilt-independent optical-figure of a nominal optical flat at cryogenic temperatures, it requires a cryogenic dewar-window system for a Fizeau interferometer outside the dewar to see through. The issue is: how to calibrate in situ the window system using the yet-to-be-calibrated nominal optical flat, and vice versa, in only one cryogenic cooldown? The proposition includes: (a) interferometric phase-map measurements with the test piece slightly offset in different transverse directions, and (b) for synthesizing the 2-dimensional WDF, an unconventional numerical scheme starting with 1-dimensional bi-direction integration. The numerical scheme helps minimize the non-uniformity in integrated noise-power distribution that results from integrating data, and thus the associated uncorrelated random noise, from raw phase-maps. The numerical scheme represents a new concept specifically for integrating noise-carrying experimental data.
Date: March 20, 2006
Creator: Gwo, D.
Partner: UNT Libraries Government Documents Department

Radiation and gas conduction heat transport across a helium dewar multilayer insulation system

Description: This report describes a method for calculating mixed heat transfer through the multilayer insulation used to insulate a 4 K liquid helium cryostat. The method described here permits one to estimate the insulation potential for a multilayer insulation system from first principles. The heat transfer regimes included are: radiation, conduction by free molecule gas conduction, and conduction through continuum gas conduction. Heat transfer in the transition region between the two gas conduction regimes is also included.
Date: October 10, 1994
Creator: Green, Michael A.
Partner: UNT Libraries Government Documents Department

Liquid helium boil-off measurements of heat leakage from sinter-forged BSCCO current leads under DC and AC conditions

Description: Liquid helium boil-off experiments are conducted to determine the heat leakage rate of a pair of BSCCO 2223 high-temperature superconductor current leads made by sinter forging. The experiments are carried out in both DC and AC conditions and with and without an intermediate heat intercept. Current ranges are from 0-500 A for DC tests and 0-1,000 A{sub rms} for AC tests. The leads are self-cooled. Results show that magnetic hysteresis (AC) losses for both the BSCCO leads and the low-temperature superconductor current jumper are small for the current range. It is shown that significant reduction in heat leakage rate (liquid helium boil-off rate) is realized by using the BSCCO superconductor leads. At 100 A, the heat leakage rate of the BSCCO/copper binary lead is approximately 29% of that of the conventional copper lead. Further reduction in liquid helium boil-off rate can be achieved by using an intermediate heat intercept. For example, at 500 K, the heat leakage rate of the BSCCO/copper binary lead is only 7% of that of the conventional copper lead when an intermediate heat intercept is used.
Date: June 1, 1995
Creator: Cha, Y.S.; Niemann, R.C.; Hull, J.R.; Youngdahl, C.A.; Lanagan, M.T.; Nakade, M. et al.
Partner: UNT Libraries Government Documents Department

Measuring the Flatness of Focal Plane for Very Large Mosaic CCD Camera

Description: Large mosaic multiCCD camera is the key instrument for modern digital sky survey. DECam is an extremely red sensitive 520 Megapixel camera designed for the incoming Dark Energy Survey (DES). It is consist of sixty two 4k x 2k and twelve 2k x 2k 250-micron thick fully-depleted CCDs, with a focal plane of 44 cm in diameter and a field of view of 2.2 square degree. It will be attached to the Blanco 4-meter telescope at CTIO. The DES will cover 5000 square-degrees of the southern galactic cap in 5 color bands (g, r, i, z, Y) in 5 years starting from 2011. To achieve the science goal of constraining the Dark Energy evolution, stringent requirements are laid down for the design of DECam. Among them, the flatness of the focal plane needs to be controlled within a 60-micron envelope in order to achieve the specified PSF variation limit. It is very challenging to measure the flatness of the focal plane to such precision when it is placed in a high vacuum dewar at 173 K. We developed two image based techniques to measure the flatness of the focal plane. By imaging a regular grid of dots on the focal plane, the CCD offset along the optical axis is converted to the variation the grid spacings at different positions on the focal plane. After extracting the patterns and comparing the change in spacings, we can measure the flatness to high precision. In method 1, the regular dots are kept in high sub micron precision and cover the whole focal plane. In method 2, no high precision for the grid is required. Instead, we use a precise XY stage moves the pattern across the whole focal plane and comparing the variations of the spacing when it is imaged by different CCDs. ...
Date: June 8, 2010
Creator: Hao, Jiangang; Estrada, Juan; Cease, Herman; Diehl, H.Thomas; Flaugher, Brenna L.; Kubik, Donna et al.
Partner: UNT Libraries Government Documents Department

D0 Solenoid Upgrade Project: Pressure Ratings for Some Chimney and Control Dewar Componenets

Description: Pressure rating calculations were done for some of the chimney and control dewar components. This engineering note documents these calculations. The table below summarizes the components looked at, and what pressure rating are. The raw engineering calculations for each of the components is given.
Date: May 25, 1993
Creator: Rucinski, R.
Partner: UNT Libraries Government Documents Department

D0 Vent Stacks

Description: There are two nitrogen/argon exhaust headers in the D0 cryogenic piping system, one for the liquid argon dewar and another for the three argon calorimeters. These headers serve two functions, venting both nitrogen exhaust from the cooling loops and cold argon gas should any argon vessel blow a relief. These headers are vacuum jacketed until they exit the building. At that point, uninsulated exhaust stacks direct the flow into the atmosphere. This note deals with the these stacks.
Date: January 22, 1988
Creator: Fuerst, J.D.
Partner: UNT Libraries Government Documents Department

Control Dewar and VLPC Bayonet Can Platform Connection Design and Analysis

Description: The four connections for the control dewar and VLPC bayonet can platform are designed, using finite element analysis, to carry all dead weight and live loads. Based on the loads applied to the platform, two 1 inch thick plates and two 3/4 inch thick brackets made of ASTM A572-Grade 42 are required. The 1 inch thick plate requires a 3/8 inch thick intermediate steel material, between the 8-inch x 4-inch x 1/4-inch boom and the plate, for load reinforcement as well as weld area reinforcement. Both the plates and the brackets require 3/4 inch steel bolt connections.
Date: July 29, 1997
Creator: Kuwazaki, A.
Partner: UNT Libraries Government Documents Department

Control Dewar Open Issues

Description: In the process of developing a design for the design report, side questions or comments arose which were not completely answered or investigated because the work was outside the scope of developing a base design. I have pored over my meeting notes and tried to list all such control dewar 'open issues' in this engineering note.
Date: October 4, 1993
Creator: Rucinski, R.
Partner: UNT Libraries Government Documents Department

Test Cryostat Nozzle

Description: This report contains the results of calculations for a resized nozzle on the D-Zero test cryostat. The nozzle neck in the inner vessel with be 6-inch schedule 10S pipe and 8-inch 10S will be used for the outer vessel. On top of the nozzle will be placed the D-Zero Endcap Calorimeter signal board feedthru dewar box. This box weighs approximately 250 lbs but the weight was conservatively taken to be 500 lbs. The allowable pressure from above does not exceed 15 psig per ASME, but it does exceed 7.5 psig required by CGA-341 therefore reinforcement is not required. Note that the reinforcement provided by the nozzle neck in combination with the excess shell thickness is probably sufficient to satisfy the ASME requirements.
Date: May 22, 1986
Creator: Wintercorn, S.J.
Partner: UNT Libraries Government Documents Department

High Pressure Source/Cryostat Relief Solutions

Description: This report addresses solutions to the potential problem of cryostat over pressurization by the nominal 65 psi MWAP LAr source dewar. Uncontrolled (by reason of failure) filling of a 15 psi MW AP cryostat by the LAr fill line could cause over pressurization by overwhelming the provided cryostat relief system. Three levels of protection against over pressurization by the source dewar are mentioned in this report; the reduced (operational) relief pressure, the source pressure regulator, and the LAr dewar cooling loop. Only the first of these is recognized by the ASME code as sufficient protection, the others provide operational convenience and avoid the loss of detector fluid. Flow limiting device solutions are not considered because of the conflicting requirement to empty and fill the cryostats rapidly (within one eight hour shift), e.g. the movement of the cryostat from the assembly hall to the collision hall, or the inverse operation.
Date: August 13, 1987
Creator: Wintercorn, S. J. & Mulholland, G. T.
Partner: UNT Libraries Government Documents Department

Cryostat Filling Limitations for Proposed Ar Dewar Pressure Increase

Description: In order to significantly decrease the amount of time required to fill the cryostats, it is desired to raise the setpoint of the 'operating' relief valve on the argon storage dewar to 20 psig from its existing 16 psig setting. This additional pressure increases the flow to the cryostats and will overwhelm the relief capacity if the temperature of the modules within these vessels is warm enough. Using some conservative assumptions and simple calculations within this note, the maximum average temperature that the modules within each cryostat can be at prior to filling from the storage dewar with liquid argon is at least 290 K.
Date: July 23, 1991
Creator: Dixon, K. & Wu, J.
Partner: UNT Libraries Government Documents Department

Dewar Testing of Coaxial Resonators at MSU

Description: Michigan State University is currently testing prototype and production cavities for two accelerator projects. 80.5 MHz {beta} = 0.085 quarter wave resonators (QWR) are being produced as part of a cryomodule for ReA3. 322 MHz {beta} = 0.53 half wave resonators (HWR) are being prototyped for a driver linac for the Facility for Rare Isotope Beams. This paper will discuss test results and how different cavity preparations effect cavity performs. Also various diagnostics methods have been developed, such as second sound quench location determination, and temperature mapping to determine hot spots from defects and multipacting location.
Date: July 1, 2012
Creator: Popielarski, J; Facco, A; Hodek, M; Marti, F; Norton, D; Velianoff, G J et al.
Partner: UNT Libraries Government Documents Department

Cryogenics for superconductors: Refrigeration, delivery, and preservation of the cold

Description: Applications in superconductivity have become widespread, enabled by advancements in cryogenic engineering. In this paper, the history of cryogenic refrigeration, its delivery, its preservation and the important scientific and engineering advancements in these areas in the last 100 years will be reviewed, beginning with small laboratory dewars to very large scale systems. The key technological advancements in these areas that enabled the development of superconducting applications at temperatures from 4 to 77 K are identified. Included are advancements in the components used up to the present state-of-the-art in refrigeration systems design. Viewpoints as both an equipment supplier and the end-user with regard to the equipment design and operations will be presented. Some of the present and future challenges in these areas will be outlined. Most of the materials in this paper are a collection of the historical materials applicable to these areas of interest.
Date: June 1, 2012
Creator: Venkatarao Ganni, James Fesmire
Partner: UNT Libraries Government Documents Department


Description: The CEBAF accelerator, a recirculating CW electron accelerator that is currently operating at Jefferson Laboratory, is in the process of having 10 new cryomodules installed to allow for the maximum beam energy to be increased from 6 GeV to 12 GeV. This upgrade required the fabrication, processing and RF qualification of 80, seven cell elliptical SRF cavities, a process that was completed in February 2012. The RF performance achieve in the vertical testing dewars has exceeded the design specification by {approx}25% and is a testament to the cavity design and processing cycle that has been implemented. This paper will provide a summary of the cavity RF performance in the vertical tests, as well as review the overall cavity processing cycle and duration for the project.
Date: July 1, 2012
Creator: Burrill, A.; Davis, G. K.; Reece, C. E.; Reilly, A. V. & Stirbet, M.
Partner: UNT Libraries Government Documents Department

LAr Dewar Coil Feed Frame Pipe Analysis (Structural Analysis of General Structures, SAGS)

Description: This frame pipe analysis addresses the D0 LAr dewar Condenser tube (coil) feed pipe thermal contraction stresses and moments. The configuration is shown in PEI drawing C-32545, Rev 0, and the parameters detailed in the letter of November 20, 1989, located in appendix A. Note that all other thermal considerations for these condensing coils have been made in D0 EN 3740.512-234. The conclusion of this report is the feed lines, previously deemed appropriate without detailed analysis, have been demonstrated to be adequately designed for the intended service and require no further investigation.
Date: January 31, 1990
Creator: Parker, A.W.
Partner: UNT Libraries Government Documents Department

D0 Silicon Upgrade: Control Dewar Venturi Calibration Explanation for Toshiba

Description: This document is intended to explain the calibration data for the venturi, FE-3253H, which is installed in the control dewar. Further, this document will help explain how to use the venturi to make mass flow measurements during typical operating conditions. The purpose of the calibration data enclosed from the Colorado Engineering Experiment Station Inc. is to experimentally show that the venturi follows the flow equation which is enclosed as Eq. 7-36 on page 155, from the Applied Fluid Dynamics Handbook. The calibration data serves to show that the Subsonic Venturi, Serial Number 611980-18, produces results predicted by the compressible subsonic flow mass flow rate equation above and to experimentally determine the discharge coefficient C. Colorado Engineering Experiment Station Inc. ran tests at 15 independent differential pressures to conclude that use of this venturi will perform according to the mass flow rate equation. In order to verify the results from the Colorado Engineering Experiment Station Inc. we have provided you with a step-by-step procedure using the values they have chosen.
Date: January 24, 1997
Creator: Kuwazaki, Andrew
Partner: UNT Libraries Government Documents Department

Argon Storage Dewar Initial Fill

Description: The argon storage dewar at the D0 Assembly Hall was filled with approximately 3100 gallons of high purity liquid argon for the first time on December 3,1990. The oxygen analyzer and high voltage test cell both indicated an oxygen impurity level between 0.4 and 0.5 ppm which is acceptable. The condenser and insulated piping sizing appears to be correct for a fill rate of a couple of hours. Insulation is required around the inlet to this piping in order to reduce the amount of filling time significantly. The graph of the level indication vs. volume of the dewar should be changed to reflect the apparent 5.2-5.4 in. offset. Another data point may be required to narrow this number down further. A majority of the time spent to fill the vessel was associated with the testing of the liquid-this time will shorten as we gain experience. Subsequent deliveries should be ordered to initiate as early in the morning as possible, this appears to be nearly an all day effort. The argon checked prior to delivery by us indicated that it was acceptable. The analysis of the argon purity that Linde provides us is merely a check that the liquid meets our agreement with them per contract, the actual purity could be much lower than what is written in their analysis results.
Date: March 21, 1991
Creator: Dixon, K.
Partner: UNT Libraries Government Documents Department

Argon Dewar Relief Set Pressure Modifications

Description: This engineering note documents the calculations of Kelly Dixon, used to determine the maximum allowable set pressure for the argon dewar low relief valve, tag number PSV620A, Anderson Greenwood Type 526J. The original setting was 16 psig. This value was chosen in order to protect against cryostat overpressurization by the source dewar (see D0 Engineering Note 115), however, the following calculations will show that the set pressure can be raised to approximately 18.5 psig, which would result in a faster filling of the cryostat, along with a higher level of liquid argon. Three other engineering notes were revised to reflect the change in set pressure according to this note. They are notes 115, 219, and 263.
Date: March 19, 1991
Creator: Wu, J.
Partner: UNT Libraries Government Documents Department

Argon Dewar Required Relief Flow Capacity

Description: This report calculates the required fire relief valve flow capacity, the required vaporizer failure relief valve flow capacity, and the required loss of vacuum relief valve flow capacity of the liquid argon storage tank in use at the D-Zero site.
Date: September 28, 1987
Creator: Fitzpatrick, J. B.
Partner: UNT Libraries Government Documents Department

D0 Silicon Upgrade: Helium and LN2 Storage Requirements for D-Zero Upgrade

Description: Calculations were done to determine a recommended size for the liquid helium storage dewar, gas helium storage tanks, and liquid nitrogen dewar requirements. I recommend a Liquid helium storage dewar with a nominal size of at least 2500 liters (660 gallons), preferably 3000 liters (792 gallons). I recommend obtaining gas helium storage tanks with a maximum allowable working pressure (MA WP) of 250 psig or greater. Combined volume to be at least 5880 cubic feet (44,000 gallons). I recommend obtaining a second liquid nitrogen dewar at D-Zero, dedicated to the refrigerator, solenoid and VLPC systems. The ideal dewar would have a volume of around 16,000 gallons. It's MAWP needs to be greater than 55 psig.
Date: April 4, 1995
Creator: Rucinski, Russ
Partner: UNT Libraries Government Documents Department

D0 Silicon Upgrade: Cryolab Control Valve Modification Information for D0-EVMF-H

Description: This engineering note documents some information regarding the solenoid magnet flow valve, EVMF. See also EN-437 'Control Dewar valve sizing' also for further information on this valve. This note documents the modification done to the valve to change it to a Cv = 0.32.
Date: October 26, 1995
Creator: Rucincki, Russ
Partner: UNT Libraries Government Documents Department