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8 GeV H- ions: Transport and injection (open access)

8 GeV H- ions: Transport and injection

Fermilab is working on the design of an 8 GeV superconducting RF H{sup -} linac called the Proton Driver. The energy of H{sup -} beam will be an order of magnitude higher than the existing ones. This brings up a number of technical challenges to transport and injection of H{sup -} ions. This paper will focus on the subjects of stripping losses (including stripping by blackbody radiation, field and residual gas) and carbon foil stripping efficiency, along with a brief discussion on other issues such as Stark states lifetime of hydrogen atoms, single and multiple Coulomb scattering, foil heating and stress, radiation activation, collimation and jitter correction, etc.
Date: May 1, 2005
Creator: Chou, W.; Bryant, H.; Drozhdin, A.; Hill, C.; Kostin, M.; Macek, R. et al.
System: The UNT Digital Library
53 MHz beam loading compensation for slip stacking in the Fermilab Main Injector (open access)

53 MHz beam loading compensation for slip stacking in the Fermilab Main Injector

Recently In-Phase and Quadrature (I&Q) was added to both the 53 MHz Feedback and Feedforward Beam Loading Compensation for Slip Stacking in the Fermilab Main Injector. With 53 MHz Feedback, we can now turn the 18 Radio Frequency (RF) Stations off down to below 100 V. In using I&Q on Feedforward, beam loading compensation to the beam on both the upper and lower frequencies of Slip Stacking can be applied as we slip the beam. I&Q theory will be discussed.
Date: May 1, 2005
Creator: Dey, J. & Kourbanis, I.
System: The UNT Digital Library
Adsorption of lanthanum to goethite in the presence of gluconate (open access)

Adsorption of lanthanum to goethite in the presence of gluconate

Adsorption of Lanthanum to Goethite in the Presence of Gluconic Acid L. C. HULL,1 S. E. PEPPER2 AND S. B. CLARK2 1Idaho National Engineering and Environmental Laboratory, Idaho Falls, ID (hulllc@inel.gov) 2Washington State University, Pullman, WA (spepper@wsu.edu), (s_clark@wsu.edu) Lanthanide and trivalent-actinide elements in radioactive waste can pose risks to humans and ecological systems for many years. Organic complexing agents, from natural organic matter or the degradation of waste package components, can alter the mobility of these elements. We studied the effect of gluconic acid, as an analogue for cellulose degradation products, on the adsorption of lanthanum, representing lanthanide and trivalent-actinide elments, to goethite, representing natural iron minearals and degradation products of waste packages. Batch pH adsorption edge experiments were conducted with lanthanum alone, and with lanthanum and gluconate at a 1:1 mole ratio. Lanthanum concentrations studied were 0.1, 1, and 10 mM, covering a range from 10% to 1000% of the calculated available adsorption sites on goethite. In the absence of gluconate, lanthanum was primarily present in solution as free lanthanum ion. With gluconate present, free lanthanum concentration in solution decreased with increasing pH as step-wise deprotonation of the gluconate molecule increased the fraction lanthanum complexed with gluconate. Adsorption to …
Date: May 1, 2005
Creator: Hull, Laurence C.; Pepper, Sarah & Clark, Sue
System: The UNT Digital Library
Advances in the understanding and operations of superconducting colliders (open access)

Advances in the understanding and operations of superconducting colliders

Chromaticity drift during injection is a well-known phenomenon in superconducting colliders, such as the Tevatron, HERA and RHIC. Imperfect compensation of the drift effects can contribute to beam loss and emittance growth. It is caused by the drift of the sextupole component in the dipole magnets due to current redistribution in its superconducting coils. Recently extensive studies of chromaticity drift were conducted at the Tevatron, aiming at the improvement of the luminosity performance in the ongoing run II. These studies included not only beam experiments, but also extensive off-line magnetic measurements on spare Tevatron dipoles. Less known, until recently, is that chromaticity drift is often accompanied by tune and coupling drift. This was recently discovered in the Tevatron. We believe that these effects are the product of systematic beam offset in conjunction with the sextupole drifts (and their compensation in the chromaticity correctors). These discoveries are most relevant to the upcoming LHC, where the drift effects will have even more dramatic consequences given the high beam current. It is therefore not a surprise that CERN has been the source of major advances in the understanding of dynamic effects during the LHC superconducting magnet development. The following will briefly review the …
Date: May 1, 2005
Creator: Annala, G.; Bauer, P.; Bottura, L.; Martens, M. A.; Sammut, N.; Velev, G. et al.
System: The UNT Digital Library
Analysis of the Use of Wind Energy to Supplement the Power Needs at McMurdo Station and Amundsen-Scott South Pole Station, Antarctica (Poster) (open access)

Analysis of the Use of Wind Energy to Supplement the Power Needs at McMurdo Station and Amundsen-Scott South Pole Station, Antarctica (Poster)

This poster summarizes the analysis of the inclusion of wind-driven power generation technology into the existing diesel power plants at two U.S. Antarctic research stations, McMurdo and Amundsen-Scott South Pole Station. Staff at the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) conducted the analysis. Available data were obtained on the wind resources, power plant conditions, load, and component cost. We then used NREL's Hybrid2 power system modeling software to analyze the potential and cost of using wind turbine generators at the two aforementioned facilities.
Date: May 1, 2005
Creator: Baring-Gould, E. I.; Robichaud, R. & McLain, K.
System: The UNT Digital Library
Angular dependence of the magnetization reversal in exchangebiased Fe/MnF2 (open access)

Angular dependence of the magnetization reversal in exchangebiased Fe/MnF2

A detailed study of exchange-biased Fe/MnF{sub 2} bilayers using magneto-optical Kerr Effect shows that the magnetization reversal occurs almost fully through domain wall nucleation and propagation for external fields parallel to the exchange bias direction. For finite angles {phi} between bias and external field the magnetization is aligned perpendicular to the field cooling direction for a limited field range for decreasing fields. For external fields perpendicular to the bias direction the magnetization aligns with the field cooling direction for descending and ascending fields before fully reversing. The field range for which the magnetization is close to perpendicular to the external field can be estimated using a simple effective field model.
Date: May 1, 2005
Creator: Arenholz, Elke & Liu, Kai
System: The UNT Digital Library
Application of independent component analysis for beam diagnosis (open access)

Application of independent component analysis for beam diagnosis

The independent component analysis (ICA) is applied to analyze simultaneous multiple turn-by-turn beam position monitor (BPM) data of synchrotrons. The sampled data are decomposed to physically independent source signals, such as betatron motion, synchrotron motion and other perturbation sources. The decomposition is based on simultaneous diagonalization of several unequal time covariance matrices, unlike the model independent analysis (MIA), which uses equal-time covariance matrix only. Consequently the new method has advantage over MIA in isolating the independent modes and is more robust under the influence of contaminating signals of bad BPMs. The spatial pattern and temporal pattern of each resulting component (mode) can be used to identify and analyze the associated physical cause. Beam optics can be studied on the basis of the betatron modes. The method has been successfully applied to the Booster Synchrotron at Fermilab.
Date: May 1, 2005
Creator: Huang, X.; Lee, S. Y.; Prebys, Eric & Tomlin, Ray
System: The UNT Digital Library
Assessment of Potential for Ion Driven Fast Ignition (open access)

Assessment of Potential for Ion Driven Fast Ignition

Critical issues and ion beam requirements are explored for fast ignition using ion beams to provide fuel compression using indirect drive and to provide separate short pulse ignition heating using direct drive. Several ion species with different hohlraum geometries are considered for both accelerator-produced and laser-produced ion ignition beams. Ion-driven fast ignition targets are projected to have modestly higher gains than with conventional heavy-ion fusion, and may offer some other advantages for target fabrication and for use of advanced fuels. However, much more analysis and experiments are needed before conclusions can be drawn regarding the feasibility for meeting the ion beam transverse and longitudinal emittances, focal spots, pulse lengths, and target stand-off distances required for ion-driven fast ignition.
Date: May 1, 2005
Creator: Logan, B. Grant; Bangerter, Roger O.; Callahan, Debra A.; Tabak,Max; Roth, Markus; Perkins, L. John et al.
System: The UNT Digital Library
B-hadron lifetimes and Delta Gamma at the Tevatron (open access)

B-hadron lifetimes and Delta Gamma at the Tevatron

The authors present new results on the lifetimes and widths of B hadrons based on 300-450 pb{sup -1} of data collected by CDF and D0 at the Fermilab Tevatron. Lifetimes were measured in semileptonic decays as well as fully reconstructed hadronic modes. A new measurement of the width difference between B{sub s} CP eigenstates, {Delta}{Lambda}/{bar {Lambda}}, in B{sub s} decays to J/{psi}{phi} is also presented.
Date: May 1, 2005
Creator: Lipton, R. J.
System: The UNT Digital Library
B lifetimes and mixing at the Tevatron (open access)

B lifetimes and mixing at the Tevatron

The authors present recent results on b-hadron lifetimes and mixing obtained from the analysis of the data collected at the Tevatron Collider by the CDF and D0 Collaborations in the period 2002-2004. Many lifetime measurements have been updated since the Summer 2004 conferences, sometimes improving significantly the accuracy. Likewise the measurement of the B{sub d} oscillation frequency has been updated. New limits on the B{sub s} oscillation frequency have been determined using for the first time Run II data.
Date: May 1, 2005
Creator: Bedeschi, Franco
System: The UNT Digital Library
B0(S) mixing, lifetime difference and rare decays at the Tevatron (open access)

B0(S) mixing, lifetime difference and rare decays at the Tevatron

Recent results on B{sub s}{sup 0} mixing, lifetime difference and rare decays obtained by the CDF and D0 collaborations using the data samples collected at the Tevatron Collider in the period 2002-2005 are presented.
Date: May 1, 2005
Creator: Burdin, Sergey
System: The UNT Digital Library
Barrier RF system and applications in Main Injector (open access)

Barrier RF system and applications in Main Injector

A novel broadband RF system--the barrier RF--has been designed, fabricated and installed in the Fermilab Main Injector (MI). It uses nanocrystal magnetic alloy called Finemet and high voltage fast MOSFET switches. The system delivers {+-}10 kV square pulses at 90 kHz. It can stack two proton batches injected from the Booster and squeeze them into the size of one so that the bunch intensity is increased. The high intensity beams have been successfully accelerated to 120 GeV with small losses. The problem of large longitudinal emittance growth is under investigation. A second system will be installed during the fall shutdown and be tested for the so-called fast stacking scheme to continuously stack up to 12 Booster batches in the MI. This system is also used for cleaning up the leaking-out dc beams from slip stacking to reduce beam loss. This work is part of the US-Japan collaborative agreement.
Date: May 1, 2005
Creator: Chou, W.; Wildman, D. & Takagi, A.
System: The UNT Digital Library
Beam-beam effects in the Tevatron Run II (open access)

Beam-beam effects in the Tevatron Run II

Electromagnetic long-range and head-on interactions of high intensity proton and antiproton beams are significant sources of beam loss and lifetime limitations in the Tevatron Collider Run II (2001-present). We present observations of the beam-beam phenomena in the Tevatron and results of relevant beam studies. We analyze the data and various methods employed in high energy physics (HEP) operation, predict the performance for planned luminosity upgrades and discuss ways to improve it.
Date: May 1, 2005
Creator: Shiltsev, V.; Alexahin, Yu.; Lebedev, V.; Lebrun, P.; Moore, R.; Sen, T. et al.
System: The UNT Digital Library
Beam collimation and machine detector interface at the International Linear Collider (open access)

Beam collimation and machine detector interface at the International Linear Collider

Synchrotron radiation, beam-gas scattering and beam halo interactions with collimators and other components in the ILC beam delivery system (BDS) would create fluxes of muons and other secondaries which could exceed the tolerable levels at a detector by a few orders of magnitude. It is shown that with a multi-stage collimation system, magnetized iron spoilers which fill the tunnel and a set of masks in the detector, one can hopefully meet the design goals. Results of modeling with the STRUCT and MARS15 codes of beam loss and energy deposition effects are presented in this paper. We focus on the collimation system and mask performance optimization, short- and long-term survivability of the critical components (spoilers, absorbers and magnets), dynamic heat loads and radiation levels in magnets and other components, and machine-related backgrounds in collider detectors.
Date: May 1, 2005
Creator: Mokhov, N. V.; Drozhdin, A. I. & Kostin, M. A.
System: The UNT Digital Library
Beam profile measurement with flying wires at the Fermilab Recycler Ring (open access)

Beam profile measurement with flying wires at the Fermilab Recycler Ring

Flying wires were installed at the Fermilab Recycler Ring for transverse beam profile measurement for both proton and antiproton beams. The following note describes the system configuration, calibration and resolution of the flying wire system, interactions between the wires and the beam, as well as analysis of the transverse beam profile in the presence of a stochastic cooling system.
Date: May 1, 2005
Creator: Carcagno, R.; Pishchalnikov, Yu.; Krider, J.; Hu, M.; Lorman, E.; Marchionni, A. et al.
System: The UNT Digital Library
Beauty production cross section measurements at E(cm) = 1.96-TeV (open access)

Beauty production cross section measurements at E(cm) = 1.96-TeV

The RunII physics program at the Tevatron started in spring 2001 with protons and antiprotons colliding at an energy of {radical}s = 1.96 TeV, and it is carrying on with more than 500 pb{sup -1} of data as collected by both the CDF and D0 experiments. Recent results on beauty production cross section measurements are here reported.
Date: May 1, 2005
Creator: D'Onofrio, Monica & U., /Geneva
System: The UNT Digital Library
Beta function measurement in the Tevatron using quadrupole gradient modulation (open access)

Beta function measurement in the Tevatron using quadrupole gradient modulation

Early in Run2, there was an effort to compare the different emittance measurements in the Tevatron (flying wires and synchrotron light) and understand the origin of the observed differences. To measure the beta function at a few key locations near the instruments, air-core quadrupoles were installed. By modulating the gradient of these magnets and measuring the effect on the tune, the lattice parameters can be extracted. Initially, the results seem to disagree with other methods. At the time, the lattice was strongly coupled due to a skew component in the main dipoles, caused by sagging of the cryostat. After a large fraction of the superconducting magnets were shimmed to remove a strong skew quadrupole component, the results now agree with the theoretical values to within 20%.
Date: May 1, 2005
Creator: Jansson, A.; Lebrun, P.; Volk, J. T. & /Fermilab
System: The UNT Digital Library
A Betatron tune fitting package for the Tevatron 21.4 MHz Schottky (open access)

A Betatron tune fitting package for the Tevatron 21.4 MHz Schottky

The Fermilab Tevatron is equipped with two independent Schottky monitors for measurement of betatron tunes, one operating at 21.4 MHz and the other at 1.7 GHz. A new front-end and related data acquisition for the 21.4 MHz resonator has been installed and commissioned during the FY04 Collider RunII. Sophisticated fitting strategies are required to analyze the spectra. Optimization of this fitting package allows us to report tune and chromaticity measurements at almost 1 Hz.
Date: May 1, 2005
Creator: Lebrun, Paul L. G.; Sen, Tanaji; You, Jian-Ming; Yuan, Zong-Wei; /Fermilab; Todesco, Ezio et al.
System: The UNT Digital Library
Betatron tune spread generation and differential chromaticity control by octupole families at Tevatron (open access)

Betatron tune spread generation and differential chromaticity control by octupole families at Tevatron

Existing Tevatron octupoles have been rearranged into four functional families. Two of these families generate betatron tune spreads in the vertical and horizontal planes whereas the other two control the differential chromaticity between the proton and antiproton helices. The calculated effect on the tunes and chromaticity is compared with direct measurements. Analytical formulas for betatron tune distribution functions are presented.
Date: May 1, 2005
Creator: Ivanov, P. M.; Alexahin, Y.; Annala, J.; Lebedev, V. A. & /Fermilab
System: The UNT Digital Library
Booster 6-GeV study (open access)

Booster 6-GeV study

A wider aperture, which has been obtained along the Booster beam line recently, brings the opportunity to run beams with the intensity higher than ever before. Sooner or later, the available RF accelerating voltage will become a new limit for the beam intensity. Extra accelerating voltages can be achieved either by increasing the RFSUM or by reducing the accelerating rate via a slower acceleration, and this motivates the 6-GeV study.
Date: May 1, 2005
Creator: Yang, Xi; Ankenbrandt, Charles M.; Pellico, William A.; Lackey, James; Padilla, Rene; /Fermilab et al.
System: The UNT Digital Library
BTeV trigger/DAQ innovations (open access)

BTeV trigger/DAQ innovations

BTeV was a proposed high-energy physics (HEP) collider experiment designed for the study of B-physics and CP Violation at the Tevatron at Fermilab. BTeV included a large-scale, high-speed trigger and data acquisition (DAQ) system, reading data from the detector at 500 Gbytes/sec and writing data to mass storage at a rate of 200 Mbytes/sec. The design of the trigger/DAQ system was innovative while remaining realistic in terms of technical feasibility, schedule and cost. This paper will give an overview of the BTeV trigger/DAQ architecture, highlight some of the technical challenges, and describe the approach that was used to solve these challenges.
Date: May 1, 2005
Creator: Votava, Margaret
System: The UNT Digital Library
Bunched beam stochastic cooling in the Fermilab Recycler Ring (open access)

Bunched beam stochastic cooling in the Fermilab Recycler Ring

Stochastic cooling with bunched beam in a linear bucket has been obtained and implemented operationally in the Fermilab Recycler Ring (RR). This is the first time that linear-rf bunched-beam stochastic cooling has been successfully used operationally in a high-energy facility. In this implementation the particle bunch length is much greater than the cooling system wavelengths, and that property is critical to the cooling success. The simultaneous longitudinal bunching enables cooling to much smaller longitudinal emittances than the coasting beam or barrier bucket system. Characteristics and limitations of bunched beam stochastic cooling are discussed.
Date: May 1, 2005
Creator: Broemmelsiek, D.; Burov, A.; Nagaitsev, S.; Neuffer, D. & /Fermilab
System: The UNT Digital Library
Bunching for shorter damping rings for the ILC (open access)

Bunching for shorter damping rings for the ILC

A variant rearrangement of the bunch trains for the ILC that enables much shorter damping rings is presented. In a particular example the {approx}2820 bunches are regrouped into {approx}550 subtrains of five adjacent bunches. These subtrains are extracted from the damping rings at {approx}1.8 {micro}s intervals, obtaining the 1ms macrobunch length of the baseline TESLA collider scenario. If the baseline damping rf frequency is 325 MHz and the kicker rise and fall times are {approx}20 ns, a ring circumference of {approx}5.8km is required. Variations of the scheme could easily reduce the circumference to {approx}4km, and faster kickers could reduce it even further.
Date: May 1, 2005
Creator: Neuffer, D.
System: The UNT Digital Library
The calculation of orbit length change of the recycler due to main injector ramp (open access)

The calculation of orbit length change of the recycler due to main injector ramp

Orbit length of beam in the Recycler changes during the Main Injector ramps. The unknown kicks from the effects generated by stray field are distributed around the ring. To estimate the changes, simulated virtual kicks are created around each lambertson, C-magnet and their bus of the Main Injector. An orbit measurement consists of the readout of all of the Recycler beam position monitors (BPMs). The orbit lengths difference is calculated by comparing the horizontal closed orbit of the beam with a reference orbit. The calculation methods are described first. The analysis presented here includes the calculation of the orbit length changes and the strength of the simulated kicks before and after LAM52 and V701 magnet bus work done.
Date: May 1, 2005
Creator: Xiao, Meiqin
System: The UNT Digital Library