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Parameter Identification of a Numerical Transport Code

Description: A parameter identification process is presented to obtain effective, resultant properties of a numerical transport code. The method is demonstrated using NUFT (Nonisothermal Unsaturated-Saturated Flow and Transportation model) [1], as a transport code, and the effective heat conductivity and thermal diffusivity as effective parameters. A numerical application example shows that effective transport code in a variety of boundary conditions.
Date: February 26, 2002
Creator: Danko, G. & Jain, A.
Partner: UNT Libraries Government Documents Department

R&D ERL: Magnetic measurements of the ERL magnets

Description: The magnet system of ERL consists of G5 solenoids, 6Q12 quadrupoles with 0.58 T/m gradient, 3D60 dipoles with 0.4 T central field, 15 and 30 degree Z-bend injection line dipole/quadrupole combined function magnets, and extraction line magnets. More details about the magnets can be found in a report by G. Mahler. Field quality in all the 6Q12 quadrupoles, 3D60 dipoles and the injection line magnets has been measured with either a rotating coil, or a Hall probe mapper. This report presents the results of these magnetic measurements.
Date: August 1, 2010
Creator: Jain, A.
Partner: UNT Libraries Government Documents Department

Specification and R and D Program on Magnet Alignment Tolerances for NSLS-II

Description: The NSLS-II light source is a proposed 3 GeV storage ring, with the potential for ultra-low emittance. Despite the reduced emittance goal for the bare lattice, the closed orbit amplification factors are on average >55 in both planes, for random quadrupole alignment errors. The high chromaticity will also require strong sextupoles and the low 3 GeV energy will require large dynamic and momentum aperture to insure adequate lifetime. This will require tight alignment tolerances ({approx} 30{micro}m) on the multipole magnets during installation. By specifying tight alignment tolerances of the magnets on the support girders, the random alignment tolerances of the girders in the tunnel can be significantly relaxed. Using beam based alignment to find the golden orbit through the quadrupole centers, the closed orbit offsets in the multipole magnets will then be reduced to essentially the alignment errors of the magnets, restoring much of the dynamic aperture and lifetime of the bare lattice. Our R&D program to achieve these tight alignment tolerances of the magnets on the girders using a vibrating wire technique, will be discussed and initial results presented.
Date: May 4, 2009
Creator: Kramer,S.L. & Jain, A. K.
Partner: UNT Libraries Government Documents Department

Field quality control through the production phase of RHIC arc dipoles

Description: The field quality in the arc dipoles built thus far for the Relativistic Heavy Ion Collider (RHIC) not only meets machine requirements but is significantly better than that expected from scaling laws based on previous large scale superconducting magnet production for particle accelerators. In this paper the authors describe the evolution of the present cross section and the design philosophy that has led to these improvements. The techniques described here have been found quite efficient to adopt in the production environment, where schedule and cost considerations become important. Moreover, the techniques developed during the R&D program have resulted in making the saturation induced harmonics negligible, despite the fact that the iron is very close to the coil.
Date: May 1, 1995
Creator: Gupta, R.; Jain, A. & Kahn, S.
Partner: UNT Libraries Government Documents Department

REALISTIC NON-LINEAR MODEL AND FIELD QUALITY ANALYSIS IN RHIC INTERACTION REGIONS.

Description: The existence of multipole components in the dipole and quadrupole magnets is one of the factors limiting the beam stability in the RHIC operations. So, a realistic non-linear model is crucial for understanding the beam behavior and to achieve the ultimate performance in RHIC. A procedure is developed to build a non-linear model using the available multipole component data obtained from measurements of RHIC magnets. We first discuss the measurements performed at different stages of manufacturing of the magnets in relation to their current state in RHIC. We then describe the procedure to implement these measurement data into tracking models, including the implementation of the multipole feed down effect due to the beam orbit offset from the magnet center. Finally, the field quality analysis in the RHIC interaction regions (IR) is presented.
Date: June 25, 2007
Creator: BEEBE-WANG,J. & JAIN, A.
Partner: UNT Libraries Government Documents Department

Design and Measurement of the NSLS II Quadrupole Prototypes

Description: The design and measurement of the NSLS-II ring quadrupoles prototypes are presented. These magnets are part of a larger prototype program described in [1]. Advances in software, hardware, and manufacturing have led to some new level of insight in the quest for the perfect magnet design. Three geometric features are used to minimize the first three allowed harmonics by way of optimization. Validations through measurement and confidence levels in calculations are established.
Date: May 4, 2009
Creator: Rehak,M.; Jain, A. K.; Skaritka, J. & Spataro, C.
Partner: UNT Libraries Government Documents Department

Design and Measurement of the NSLS II Sextupoles

Description: The Sextupole magnets for the National Synchrotron Light Source II (NSLS-II) have stringent performance requirements. These magnets have a faceted pole profile that departs from the cubic shape due to constraints imposed by the vacuum chamber. Various geometric features were used to fine tune and minimize the harmonics. Prototypes have been built and measured and have satisfactory field performance.
Date: May 4, 2009
Creator: Spataro,C.; Jain, A.K.; Rehak, M & Skaritka, J.
Partner: UNT Libraries Government Documents Department

Statistical analysis of multipole components in the magnetic field of the RHIC arc regions

Description: The existence of multipolar components in the dipole and quadrupole magnets is one of the factors limiting the beam stability in the RHIC operations. Therefore, the statistical properties of the non-linear fields are crucial for understanding the beam behavior and for achieving the superior performance in RHIC. In an earlier work [1], the field quality analysis of the RHIC interaction regions (IR) was presented. Furthermore, a procedure for developing non-linear IR models constructed from measured multipolar data of RHIC IR magnets was described. However, the field quality in the regions outside of the RHIC IR had not yet been addressed. In this paper, we present the statistical analysis of multipolar components in the magnetic fields of the RHIC arc regions. The emphasis is on the lower order components, especially the sextupole in the arc dipole and the 12-pole in the quadrupole magnets, since they are shown to have the strongest effects on the beam stability. Finally, the inclusion of the measured multipolar components data of RHIC arc regions and their statistical properties into tracking models is discussed.
Date: May 4, 2009
Creator: Beebe-Wang,J. & Jain, A.
Partner: UNT Libraries Government Documents Department

Total Neutron Average Cross Sections in the KeV Region and the Optical Model

Description: The average total neutron cross sections for Nb, Mo, Rh, Ag, Cd, and In are measured at 10 to 100 kev, and the values obtained are used to calculate the optical-model parameters of the nuclei. The neutron energies used fall in the region of the P-wave giant resonances in these nuclei. (T.F.H.) 45Z6 The problem of the evolution of the amounts of nuclides during radioactive transformations is resolved according to the classical laws of radioactivity by using systematics in which the nuclides and their nuclear parameters are indexed. This method involves a simple classification of the nuclear parameters according to their nature. It leads to a matrix equation, which cand be solved by a computer program. Calculations have been made with the IBM 709094 computer. (auth)
Date: September 10, 1963
Creator: Jain, A. P.; Chrien, R. E.; Moore, J. A. & Palevsky, H.
Partner: UNT Libraries Government Documents Department

Energy implications of CO{sub 2} stabilization. Final report

Description: Analysis of carbon emissions paths stabilizing atmospheric CO{sub 2} in the 350--750 ppmv range reveals that implementing the UN Climate Convention will become increasingly difficult as the stabilization target decreases because of increasing dependence on carbon-free energy sources. Even the central Intergovernmental Panel on Climate Change scenario (IS92a) requires carbon-free primary power by 2050 equal to the humankind`s present fossil-fuel-based primary power consumption {approximately}10 TW (1 TW = 10{sup 12} W). The authors describe and critique the assumptions on which this projection is based, and extend the analysis to scenarios in which atmospheric CO{sub 2} stabilizes. For continued economic growth with CO{sub 2} stabilization, new, cost-effective, carbon-free technologies that can provide primary power of order 10 TW will be needed in the coming decades, and certainly by mid-century, in addition to improved economic productivity of primary energy.
Date: December 1, 1997
Creator: Hoffert, M.I.; Caldeira, K. & Jain, A.K.
Partner: UNT Libraries Government Documents Department

BEAM-BASED MEASUREMENTS OF PERSISTENT CURRENT DECAY IN RHIC.

Description: The two RHIC rings are equipped with superconducting dipole magnets. At injection, induced persistent currents in these magnets lead to a sextupole component. As the persistent currents decay with time, the horizontal and vertical chromaticities change. From magnet measurements of persistent current decays, chromaticity changes in the machine are estimated and compared with chromaticity measurements.
Date: June 18, 2001
Creator: FISCHER,W.; JAIN,A. & TEPIKIAN,S.
Partner: UNT Libraries Government Documents Department

SKEW QUADRUPOLES IN RHIC DIPOLE MAGNETS AT HIGH FIELDS.

Description: In the RHIC arc dipoles, the center of the cold mass lies above the center of the cryostat. At the maximum design field, the magnetic flux lines leak through the yoke to the asymmetrically located cryostat, which provides an additional return path. This introduces a systematic top-bottom asymmetry leading to a skew quadrupole term at high fields. A similar asymmetry is also created by any difference in weights of the upper and the lower yoke halves. Data from measurements of several RHIC dipoles are presented to study this effect. In the current production series of the RDIC dipoles, an attempt is made to compensate the effect of the cryostat by an asymmetry in the iron yoke. Seven dipoles with this type of yoke have been cold tested, and show a reduced saturation in the skew quadrupole term, as expected.
Date: June 11, 1995
Creator: JAIN, A.; GUPTA, P.; THOMPSON, P. & WANDERER, P.
Partner: UNT Libraries Government Documents Department

FIELD QUALITY CONTROL THROUGH THE PRODUCTION PHASE OF RHIC ARC DIPOLES.

Description: The field quality in the arc dipoles built thus far for the Relativistic Heavy Ion Collider (RHIC) not only meets machine requirements, but is significantly better than that expected from scaling laws based on previous large scale superconducting magnet production for particle accelerators. In this paper we describe the evolution of the present cross section and the design philosophy that has led to these improvements. The techniques described here have been found quite efficient to adopt in the production environment, where schedule and cost considerations become important. Moreover, the techniques developed during the R and D program have resulted in making the saturation induced harmonics negligible, despite the fact that the iron is very close to the coil.
Date: May 1, 1995
Creator: GUPTA,R.; JAIN,A. & KAHN,S.
Partner: UNT Libraries Government Documents Department

Skew quadrupole in RHIC dipole magnets at high fields

Description: In the RHIC arc dipoles, the center of the cold mass lies above the center of the cryostat. At the maximum design field, the magnetic flux lines leak through the yoke to the asymmetrically located cryostat, which provides an additional return path. This introduces a systematic top-bottom asymmetry leading to a skew quadrupole term at high fields. A similar asymmetry is also created by any difference in weights of the upper and the lower yoke halves. Data from measurements of several RHIC dipoles are presented to study this effect. In the current production series of the RHIC dipoles, an attempt is made to compensate the effect of the cryostat by an asymmetry in the iron yoke. Seven dipoles with this type of yoke have been cold tested, and show a reduced saturation in the skew quadrupole term, as expected.
Date: July 1, 1995
Creator: Jain, A.; Gupta, P.; Thompson, P. & Wanderer, P.
Partner: UNT Libraries Government Documents Department

TESTING AND EVALUATION OF SUPERCONDUCTING CABLES FOR THE LHC.

Description: As one of the activities of the US-LHC Accelerator Project, BNL is testing short samples of superconducting cables that will be used in the main LHC dipoles and quadrupoles. The purpose of these tests is to verify that the reels of superconducting cables as supplied by the vendors meet the required critical current specifications. The short-sample testing facility and the computer-assisted testing techniques for acquiring the data will be described. We also describe the data analysis, data storage, and data transmission methods.
Date: March 29, 1999
Creator: THOMAS,R.; GHOSH,A.; MCCHESNEY,D. & JAIN,A.
Partner: UNT Libraries Government Documents Department

The nuclear structure of deformed odd-odd nuclei: Experimental and theoretical investigations

Description: Previous surveys of experimental level structure in deformed odd-odd nuclei have been updated with recent results for the lanthanide and actinide regions. The relative strengths of the effective neutron-proton interaction derived from these data are compared. The predictive power of a semi-empirical model for level structure in deformed odd-odd nuclei is demonstrated. Comparison is made with recent Hartree-Fock calculations of selected nuclei.
Date: June 6, 1988
Creator: Hoff, R.W.; Jain, A.K.; Sood, P.C. & Sheline, R.K.
Partner: UNT Libraries Government Documents Department

Mimicking bipolar sextupole power supplies for low-energy operations at RHIC

Description: RHIC operated at energies below the nominal ion injection energy of E=9.8 GeV/u in 2010. Earlier test runs and magnet measurements indicated that all defocusing sextupole unipolar power supplies should be reversed to provide the proper sign of chromaticity. However, vertical chromaticity at E=3.85 GeV/u with this power supply configuration was still not optimal. This uncertainty inspired a new machine configuration where only half of the defocusing sextupole power supplies were reversed, taking advantage of the flexibility of the RHIC nonlinear chromaticity correction system to mimic bipolar sextupoles. This configuration resulted in a 30 percent luminosity gain and eliminated the need for further polarity changes for later 2010 low energy physics operations. Here we describe the background to this problem, operational experience, and RHIC online model changes to implement this solution.
Date: March 28, 2011
Creator: Montag, C.; Bruno, D.; Jain, A.; Robert-Demolaize, G.; Satogata, T. & Tepikian, S.
Partner: UNT Libraries Government Documents Department

Vibration Measurements to Study the Effect of Cryogen Flow in Superconducting Quadrupole.

Description: The conceptual design of compact superconducting magnets for the International Linear Collider final focus is presently under development. A primary concern in using superconducting quadrupoles is the potential for inducing additional vibrations from cryogenic operation. We have employed a Laser Doppler Vibrometer system to measure the vibrations in a spare RHIC quadrupole magnet under cryogenic conditions. Some preliminary results of these studies were limited in resolution due to a rather large motion of the laser head as well as the magnet. As a first step towards improving the measurement quality, a new set up was used that reduces the motion of the laser holder. The improved setup is described, and vibration spectra measured at cryogenic temperatures, both with and without helium flow, are presented.
Date: June 25, 2007
Creator: He,P.; Anerella, M.; aydin, S.; Ganetis, G. Harrison, M.; Jain, A. & Parker, B.
Partner: UNT Libraries Government Documents Department

Small gap magnet prototype measurements for eRHIC

Description: In this paper we present the design and prototype measurement of small gap (5mm to 10 mm aperture) dipole and quadrupole for the future high energy ERL (Energy Recovery Linac). The small gap magnets have the potential of largely reducing the cost of the future electron-ion collider project, eRHIC, which requires a 10GeV to 30 GeV ERL with up to 6 energy recovery passes (3.8 km each pass). We also studied the sensitivity of the energy recovery pass and the alignment error in this small magnets structure and countermeasure methods.
Date: May 23, 2010
Creator: Hao, Y.; He, P.; Jain, A.; Mahler, G.; Meng, W.; Tuozzolo, J. et al.
Partner: UNT Libraries Government Documents Department