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UCRL Orbit Program

Description: The following report records the use of the double-precision THEMIS code to integrate the motion of Mars and Venus in order to obtain a complete set of rectangular equatorial coordinates over the interval 1600-2000 A.D.
Date: July 15, 1958
Creator: Levee, Richard & Brady, Joseph L.
Partner: UNT Libraries Government Documents Department

Operations with the digital orbit feedback system in the NSLS x-ray ring

Description: The digital filtering and eigenvector decomposition-based orbit correction is performed by two dedicated HP 742/743 rt micros which communicate with Motorola CPU based orbit-measuring and orbit-correction systems. The correction algorithm in the DFbk was orthogonalized with respect of the analog global harmonic feedback. Operational results concerning improvements in the noise suppression at low frequencies and especially in the dc drift as well as in the orbit stability are shown. Efforts are underway to improve the resolution of the orbit measuing system and the sampling rate using 16 bit 400 kHz ADC`s which will allow orbit sampling with high resolution at 4 kHz frequency.
Date: May 1, 1996
Creator: Bozoki, E.; Rammamorthy, S.; Singh, O.; Tang, Y. & Friedman, A.
Partner: UNT Libraries Government Documents Department

Global DC closed orbit correction experiment on the NSLS x-ray ring

Description: In this note are described the global DC closed orbit correction experiments conducted on the X-ray ring at National Synchrotron Light Source (NSLS). The beam response matrix, defined as beam motion at BPM locations per unit kick by corrector magnets, was measured and then inverted using the technique of singular value decomposition (SVD). The product of the inverted matrix and the difference orbit gives the incremental kick strengths necessary to correct the orbit. As a result, the r.m.s. orbit error around the ring was reduced from 208 {mu}m to 61 {mu}m.
Date: September 15, 1992
Creator: Chung, Y.; Decker, G. & Evans, K.
Partner: UNT Libraries Government Documents Department

Normal mode tunes for linear coupled motion in six dimensional phase space. Informal report

Description: The motion of a particle in 6-dimensional phase space in the presence of linear coupling can be written as the sum of 3 normal mode. A cubic equation is found for the tune of the normal modes, which allows the normal mode tune to be computed from the 6 x 6 one turn transfer matrix. This result is similar to the quadratic equation found for the normal mode tune for the motion of a particle in 4-dimensional phase space. These results are useful in tracking programs where the one turn transfer matrix can be computed by multiplying the transfer matrices of each element of the lattice. The tune of the 3 normal modes for motion in 6-dimensional phase space can then be found by solving the cubic equation. Explicit solutions of the cubic equation for the tune are given in terms of the elements of the 6 x 6 one turn transfer matrix.
Date: January 1, 1995
Creator: Parzen, G.
Partner: UNT Libraries Government Documents Department

The Los Alamos Photon Counting Detector Debris Detection Project: An update

Description: At Los Alamos, the authors have been pursuing a project for space debris detection using a photon counting detector with high spatial and time resolution. By exploiting the three dimensionality of the high quality data, they expect to be able to detect an orbiting object of size below 2 cm, using a moderate size telescope and state-of-the-art photon counting detector. A working tube has been used to collect skyward looking data during dusk. In this paper, they discuss the progress in the development of detector and data acquisition system. They also report on analysis and results of these data sets.
Date: March 1, 1995
Creator: Ho, Cheng; Priedhorsky, W.; Baron, M. & Casperson, D.
Partner: UNT Libraries Government Documents Department

A COMPARISON OF SEVERAL LATTICE TOOLS FOR COMPUTATION OF ORBIT FUNCTIONS OF AN ACCELERATOR

Description: The values of orbit functions for accelerator lattices as computed with accelerator design programs may differ between different programs. For a simple lattice, consisting of identical constant-gradient bending magnets, the functions (horizontal and vertical betatron tunes, dispersions, closed orbit offsets, orbit lengths, chromaticities etc.) can be evaluated analytically. This lattice was studied with the accelerator physics tools SYNCH [1], COSY INFINITY [2], MAD [3], and TEAPOT [4]. It was found that while all the programs give identical results at the central design momentum, the results differ substantially among the various lattice tools for non-zero momentum deviations. Detailed results and comparisons are presented.
Date: May 12, 2003
Creator: COURANT, E. DTRBOJEVIC,D. BERG,S. J. GARREN,A. A. TALMAN, R.
Partner: UNT Libraries Government Documents Department

Progress Report for UNLV High Pressure Science and Engineering Center

Description: In this report we present results of an in-depth analysis of the SP error densities for 29 satellites. These satellites were divided into three groups--Low Earth Orbit (LEO), Near Circular Orbit (NCO) and Highly Eccentric Orbit (HEO). Included in the first group were those satellites with eccentricities of less than 0.2 and perigees below 450km. The second group included satellites in near circular orbits (eccentricities of less than 0.015) and perigees from 700km to 1500km. The third group consisted of those satellites that were in highly eccentric orbits, namely those with eccentricities greater than 0.2. These satellites have perigees far into the thermosphere. Table 1 contains a summary of the orbit characteristics for the 29 satellites. In our study we attempted to unravel and elucidate the networks of relationships above. The satellite groupings and the report are organized in a way that reflects these efforts. We begin in Section 2 with a summary of the methods used in our analysis. One objective in this study was to establish a baseline for future work in satellite orbit propagators. Section 2 contains descriptions of the SP, truth orbits, and the satellite observation data used to establish this baseline. In the report we show how satellite error densities evolve in time up to thirty-six hours. We present error profiles, error histograms, rms errors and 95/9970 confidence limits for the along-track cross-track, and radial axes of motion for satellites in each of the three groupings. We present results of a regression analysis that establishes a physical model of the error densities. We also link the errors in the various regimes to the quality and quantity of the observational data.
Date: November 20, 1998
Creator: Mailhiot, C.; Pepper, D.; Lindle, D. & Nicol, M.
Partner: UNT Libraries Government Documents Department

The elliptical multipole wiggler project

Description: The elliptical multipole wiggler (EMW) has been designed, constructed, and installed in the X13 straight section of the NSLS X-ray Ring. The EMW generates circularly polarized photons in the energy range of 0.1-10 keV with AC modulation of polarization helicity. The vertical magnetic field of 0.8 T is produced by a hybrid permanent magnet structure with a period of 16 cm. The horizontal magnetic field of 0.22 T is generated by an electromagnet, the core of which is fabricated from laminated iron to operate with a switching frequency up to 100 Hz. There are dynamic compensation trim magnets at the wiggler ends to control the first and second field integrals with very high accuracy throughout the AC cycle. The residual closed orbit motion due to the electromagnet AC operation is discussed.
Date: June 1, 1995
Creator: Gluskin, E.; Frachon, D. & Ivanov, P.M.
Partner: UNT Libraries Government Documents Department

Paraxial expansion of a static magnetic field in a ring accelerator

Description: In the paraxial approximation, trajectories of beam particles in a ring accelerator are computed expanded in powers of lateral displacements and slopes from a closed reference orbit. To do this, one needs first the expanded expressions of the magnetic field and potentials producing the particle motion. This is derived here in a most general form.
Date: June 1, 1995
Creator: Teng, L.C.
Partner: UNT Libraries Government Documents Department

High velocity impact experiment (HVIE)

Description: The HVIE space project was conceived as a way to measure the absolute EOS for approximately 10 materials at pressures up to {approximately}30 Mb with order-of-magnitude higher accuracy than obtainable in any comparable experiment conducted on earth. The experiment configuration is such that each of the 10 materials interacts with all of the others thereby producing one-hundred independent, simultaneous EOS experiments The materials will be selected to provide critical information to weapons designers, National Ignition Facility target designers and planetary and geophysical scientists. In addition, HVIE will provide important scientific information to other communities, including the Ballistic Missile Defense Organization and the lethality and vulnerability community. The basic HVIE concept is to place two probes in counter rotating, highly elliptical orbits and collide them at high velocity (20 km/s) at 100 km altitude above the earth. The low altitude of the experiment will provide quick debris strip-out of orbit due to atmospheric drag. The preliminary conceptual evaluation of the HVIE has found no show stoppers. The design has been very easy to keep within the lift capabilities of commonly available rides to low earth orbit including the space shuttle. The cost of approximately 69 million dollars for 100 EOS experiment that will yield the much needed high accuracy, absolute measurement data is a bargain!
Date: February 1, 1998
Creator: Toor, A.; Donich, T. & Carter, P.
Partner: UNT Libraries Government Documents Department

Global orbit feedback utilizing analog and digital technologies

Description: At the NSLS, an analog global orbit feedback system is used in regular operations, and a digital global orbit feedback system is available in machine physics studies on the X-Ray Ring. Here, the authors discuss the relative merits of utilizing analog and digital technology in orbit feedback. Results of experiments are reported characterizing the performance of the analog and digital systems when operated individually or together. They give their thoughts on plans for future development of the orbit feedback systems at the NSLS.
Date: July 1997
Creator: Singh, O.; Tang, Y.; Ramamoorthy, S.; Krinsky, S. & Yu, L. H.
Partner: UNT Libraries Government Documents Department

Fast ion orbits in spherical tokamaks

Description: In a spherical tokamak, the 1/R variation of the toroidal field is extreme, and for a given value of the safety factor a relatively low average toroidal field can be used, together with large plasma current and large plasma minor radius and elongation. The poloidal and toroidal fields are then of similar size. In consequence, the orbits of fast ions depart considerably from the guiding center orbits because of gyromotion in the small magnetic fields in the low field side.
Date: July 20, 1995
Creator: Solano, E.R.
Partner: UNT Libraries Government Documents Department

Relativistic charged particle in the dipole-sphere configuration I. Classical and semiclassical surface orbits

Description: The classical and semiclassical orbits of a relativistic charged particle on a rotating sphere threaded by a magnetic dipole field are examined. The rotational and dipole axes are in general not aligned. Several physically distinct regimes emerge, depending on the relative sizes of the total energy, canonical azimuthal angular momentum, and magnetic field strength. Magnetic flux enclosed by orbits is quantised very close to the poles. Application of this system to neutron star magnetic fields and questions for future research are outlined.
Date: January 1, 1997
Creator: Gopinath, K.S.; Kennedy, D.C. & Gelb, J.M.
Partner: UNT Libraries Government Documents Department

Correction of closed orbit distortions in the horizontal direction

Description: Many computer programs with a variety of algorithms exist for controlling the closed orbit in synchrotrons. The scope of this note is rather modest in comparison. Based on a simple model, a study has been made to find out statistically how much kick angle is needed by each steering element and how much residual closed orbit deviation should be expected when the closed orbit is steered to go through the center of seven position monitors (M{sub 2} through M{sub 8}) in each cell. Seven independent kicks are supplied by two trim dipoles B{sub U} and B{sub D}, and six steering elements (H{sub 1} through H{sub 6}) with H{sub 3} and H{sub 4} assumed to have the same kick angle. If it is necessary to remove H{sub 3} to make a space there for a correction skew quadrupole (in every other cell), the kick angle of H{sub 4} would have to be doubled.
Date: February 1, 1988
Creator: Ohnuma, S.
Partner: UNT Libraries Government Documents Department

Characterization and equalization of the AC responses of the corrector magnets for the APS local orbit feedback system

Description: Local feedback for the APS storage ring uses local bumps to control the position and angle of the positron beam through each x-ray source point. Induced eddy currents in the aluminum vacuum chamber dominate the AC characteristics of the corrector magnetic fields. Small differences in the geometries at each magnet location change the eddy current effects and result in bump closure errors which must be reduced in order to minimize the coupling between each of the many local loops and the global control loop. By a combination of flux-damping coils, flux-shielding copper sheets, and a set of steel laminations for end-flux clamping, the differences of the eddy current effects between two corrector magnets were reduced from 0.18 Gm/A to 0.035 Gm/A in the frequency span of 0.1-100 Hz.
Date: August 1, 1997
Creator: Doose, C. & Kim, S.H.
Partner: UNT Libraries Government Documents Department

Dispersion in the presence of strong transverse wakefields

Description: To minimize emittance growth in a long linac, it is necessary to control the wakefields by correcting the beam orbit excursions. In addition, the particle energy is made to vary along the length of the bunch to introduce a damping, known as the BNS damping, to the beam break-up effect. In this paper, the authors use a two-particle model to examine the relative magnitudes of the various orbit and dispersion functions involved. The results are applied to calculate the effect of a closed orbit bump and a misaligned structure. It is shown that wake-induced dispersion is an important contribution to the beam dynamics in long linacs with strong wakefields like SLC.
Date: July 1, 1997
Creator: Assmann, R. & Chao, A.
Partner: UNT Libraries Government Documents Department

Fast ion physics from neutral particle analysis on the large helical device

Description: Time-resolved measurements of the energetic ion distribution from different viewing angles allow study of some important aspects of stellarator physics. Examples from the Advanced Toroidal Facility (ATF) of measurements of the ion distribution function and the variation of orbits with pitch {nu}{parallel}/{nu} and electric field are used to illustrate some of these points; ATF`s magnetic configuration was similar to that of the Large Helical Device (LHD). Silicon ion-implanted detectors should allow measurements of the ion distribution function that are not practical with conventional neutral particle analyzers (NPAs) on LHD. Initial implementation of a silicon-detector NPA array on LHD is discussed.
Date: December 1, 1997
Creator: Lyon, J.F. & Spong, D.A.
Partner: UNT Libraries Government Documents Department

Normal mode tunes for linear coupled motion in six dimensional phase space

Description: The motion of a particle in 6-dimensional phase space in the presence of linear coupling can be written as the sum of 3 normal modes. A cubic equation is found for the tune of the normal modes, which allows the normal mode tunes to be computed from the 6 x 6 one turn transfer matrix. This result is similar to the quadratic equation found for the normal mode tunes for the motion of a particle in 4-dimensional phase space. These results are useful in tracking programs where the one turn transfer matrix can be computed by multiplying the transfer matrices of each element of the lattice. The tunes of the 3 normal modes for motion in 6-dimensional phase space can then be found by solving the cubic equation. Explicit solutions of the cubic equation for the tune are given in terms of the elements of the 6 x 6 one turn transfer matrix.
Date: May 1995
Creator: Parzen, G.
Partner: UNT Libraries Government Documents Department

Close Encounters of Asteroids and Comets to Planets

Description: This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The authors find by numerical simulations that the elongated-potato shape that is characteristic of Earth-crossing asteroids (ECAs) is likely the result of previous close tidal encounters with Earth. Some meteoroids graze the atmosphere of Earth before returning to space (at reduced speed). They used a spherical atmospheric model to study such grazers to find the condition under which they are captured into gravitationally bound orbits around Earth. They find that for about every thousand iron asteroids that hit the Earth, one is captured into a gravitational-bound orbit. Some fraction of these captured objects will have their orbits stabilized for many revolutions by tidal encounters with the Moon and the sun. They have also studied how the damage produced by such grazing and near-grazing asteroids differs from that produced by asteroids that hit Earth more directly.
Date: July 9, 1999
Creator: Hills, J.G.; Goda, M.P. & Solem, J.C.
Partner: UNT Libraries Government Documents Department

Investigations on the possible beneficial effects of a centered orbit on the performance of the low beta-y lattice

Description: The APS storage ring is routinely operated with beam steering for the users. The resulting orbit distortions (local bumps at the source point locations might reach 1 to 2 mm) could have a detrimental impact on the lattice performance via the off-centered path of the beam in the sextupoles. Resulting effects could include the following: modulation of the lattice functions, emittance growth, dynamic aperture and energy acceptance reduction, and lifetime reduction. The goal of the present study was to make a comparative analysis of the performance of the low beta-y optics when the machine is operated with the user`s orbit and with a centered orbit. Theoretical investigations as well as results of machine studies performed during the October--November run are presented in this Note. Since, to some extend, gradient errors could also induce similar perturbations, the unambiguous identification of the source of errors might be difficult. Some possibilities for discriminating between the different errors are also discussed.
Date: March 1, 1998
Creator: Ropert, A.
Partner: UNT Libraries Government Documents Department

Phase mixing of chaotic orbits as an irreversible ''relaxation'' mechanism

Description: Orbits that are chaotic will tend to phase-mix exponentially through their accessible phase space. This phenomenon, commonly called ''chaotic mixing'', stands in marked contrast to phase mixing of regular orbits. It is inherently irreversible, and thus its associated e-folding time scale sets a condition on any process envisioned for emittance compensation. Accordingly, two questions arise. First, under what conditions does chaotic mixing manifest itself in beams? Second, when it is active, over what time scale does it operate? The work described here is part of an ongoing effort to answer these questions.
Date: January 15, 2002
Creator: al., C.L. Bohn et
Partner: UNT Libraries Government Documents Department