108746136
Anti-Proton Source Beam Position System
The TeV I Beam Position Monitor (BPM) system is designed to provide a useful diagnostic tool during the commissioning and operational phases of the antiproton source. Simply stated the design goal is to provide single turn position information for intensities of > 1x10/sup 9/ particles, and multi-turn (clocked orbit) information for beam intensities of > 1x10/sup 7/ particles, both with sub-millimeter resolution. It is anticipated that the system will be used during commissioning for establishing the first turn through the Debuncher and Accumulator, for aligning injection orbits, for providing information necessary to correct closed orbits, and for measuring various machine parameters (e.g. tunes, dispersion, aperture, chromaticity). During normal antiproton operation the system will be used to monitor the beam position throughout the accumulation process.
121309706
Measurements of magnet quench levels induced by proton beam spray
A superconducting dipole magnet was installed in the Fermilab primary beam line. Targets were inserted in the proton beam upstream of the magnet and measurements made of the energy deposition within the magnet sufficient to cause quenching. The quench levels were 25 mW/g for 1 sec beam spill and 1 mJ/g for a spill of 1 msec or less. In comparison, the energy deposition at the extraction septum was 0.6 mJ/g.
55383487
Operational Experience with Tevatron I Antiproton Source
The secondaries are transported down the AP2 line into the Debuncher ring. The Debdncher ring has a 207 x 23~ transverse acceptance and 4% momentum acceptance. The antiprotons are then rotated using 4.2 MV of 53 MHz R.F. to .4% Ap/p in 80 turns and the adIabatically debunched to .2% APIP. The antiproton are then stochastically cooled for 2 seconds in the transverse planes with 2-4 GHz cooling systems to 771 x 77. The antiproton are then extracted from the Debuncher and transported across the D/A line to the Accumulator.
46560389
Helium Refrigeration System and Cryogenic System for Superconducting Switchyard Magnets at Fermilab
The first Fermilab Satellite Refrigerator produced from commercially built components has been operated in the Switchyard in a stand alone mode. After some initial shakedown runs, it has been used to cool two magnetically opposed superconducting magnets in the external beam line to the Meson Laboratory. This equipment was installed as a test of the cryogenic system to be used in converting the entire major horizontal bend to superconducting magnets (currently containing 56 conventional 10 foot dipoles). We report here on the successful operation of the refrigerator, our operating experience with the cryo nic system, and the successful transport of 1.8 x 10'1 350 GeV protons per pulse through the magnets. The complete system was designed and built by Fermilab personnel. Process and component specification and design were shared by Fermilab and an independent consulting firm.1
45030934
Superconducting Delay Line for Stochastic Cooling Filters
The stochastic cooling system of the antiproton source at Fermilab uses notch filters for reducing the feedback power at frequencies corresponding to particles in the core. At the same time these filters assist in shaping the gain vs. momentum in the stack tail. These filters, therefore, must attenuate all the harmonics of the revolution frequency (629 kHz) in the operating frequency band (1-2 GHz). They require components providing delays of 1.59 microseconds with a minimum of attenuation and undesirable distortion in this passband. Transmission lines providing such delays are typically 328 m long, have a rather large diameter, and are fabricated from a high conductivity material to keep the attenuation sufficiently low. The use of superconductors allows a dramatic reduction in the diameter, total size, and cost of this component in spite of the added cryogenic requirements. The authors measured the performance of two such cables in order to demonstrate the feasibility of the superconducting cable-notch filter concept. The first cable is an 84 m long superconducting coax consisting of a solid Niobium inner conductor inside a teflon dielectric, a lead outer conductor, and an outer jacket of mylar tape. The second cable is a 1.0 km long coaxial line more » with an inner conductor of lead-plated copper wire, a FEP teflon dielectric, and an outer conductor of leadplated copper tape wrapped with mylar. This paper discusses the results of performance testing of both cables and assesses their compatibilities with notch filters. « less
117708238
STACKTAIL MOMENTUM COOLING IN THE FERMILAB ANTIPROTON SOURCE
32493630
Computer Modeling of Internal Targets in Electron Storage Rings
The effect of thin (1-50 ¿gm/cm2) internal targets on beam quality in electron storage rings is evaluated. The internal target is modeled assuming that scattering is the result of elastic collisions between the beam electrons and the target nuclei. A screened coulomb potential is used and single and plural scattering mechanisms are included. A storage ring particle tracking code, DIMAT, was modified to include the internal target model and used to obtain the results discussed. Beam particle loss distributions and beam envelope "growth times" are given and discussed in light of damping mechanisms inherent in electron storage ring designs.
119304943
First observation of the decays $\bar{B}^0_{(s)}\to D_s^+K^-\pi^+\pi^-$ and $\bar{B}^0_s\to D_{s1}(2536)^+\pi^-$
The first observation of the decays $\bar{B}^0_{s}\to D_s^+K^-\pi^+\pi^-$ and $\bar{B}^0\to D_s^+K^-\pi^+\pi^-$ are reported using an integrated luminosity of 1.0 fb$^{-1}$ recorded by the LHCb experiment. The branching fractions, normalized with respect to $\bar{B}^0_{s}\to D_s^+\pi^-\pi^+\pi^-$ and $\bar{B}^0_{s}\to D_s^+K^-\pi^+\pi^-$, respectively, are measured to be {\br(\bar{B}^0_{s}\to D_s^+K^-\pi^+\pi^-)\over\br(\bar{B}^0_{s}\to D_s^+\pi^-\pi^+\pi^-)} &= (5.2\pm0.5\pm0.3)\times10^{-2}, {\br(\bar{B}^0\to D_s^+K^-\pi^+\pi^-)\over\br(\bar{B}^0_{s}\to D_s^+K^-^\pi^+\pi^-)} &= 0.54\pm0.07\pm0.07, where the first uncertainty is statistical and the second is systematic. The $\bar{B}^0_{s}\to D_s^+K^-\pi^+\pi^-$ decay is of particular interest as it can be used to measure the weak phase $\gamma$. First observation of the $\bar{B}^0_s\to D_{s1}(2536)^+\pi^-, D_{s1}^+\to D_s^+\pi^-\pi^+$ decay is also presented, and its branching fraction relative to $\bar{B}^0_{s}\to D_s^+\pi^-\pi^+\pi^-$ is found to be {\br(\bar{B}^0_s\to D_{s1}(2536)^+\pi^-, D_{s1}^+\to D_s^+\pi^-\pi^+)\over\br(\bar{B}^0_{s}\to D_s^+\pi^-\pi^+\pi^-)} &= (4.0\pm1.0\pm0.4)\times10^{-3}.
123558759
Polarization transfer in the O-16 (e-polarized ,e-prime p-polarized) N-15 reaction
119301317
Measurement of the inelastic pp cross-section at a centre-of-mass energy of s$$ \sqrt{s} $$ = 7 TeV
A bstractThe cross-section for inelastic proton-proton collisions, with at least one prompt long-lived charged particle of transverse momentum pT> 0.2GeV/c in the pseudorapidity range 2.0 < η < 4.5, is measured by the LHCb experiment at a centre-of-mass energy of s$$ \sqrt{s} $$ = 7 TeV. The cross-section in this kinematic range is determined to be σinelacc = 55.0 ± 2.4 mb with an experimental uncertainty that is dominated by systematic contributions. Extrapolation to the full phase space, using Pythia 6, yields σinel = 66.9 ± 2.9 ± 4.4 mb, where the first uncertainty is experimental and the second is due to the extrapolation.

45908480
Multi-GeV Electron Linac-Pulse Stretcher Design Options
The Linac-Pulse Stretcher Ring system is evaluated as a design for a high duty factor (> 90%), intense (240 ¿A), electron accelerator for operation in the 0.5 to multi-GeV (> 4 GeV) region. Options within this system are discussed in light of their predicted initial and operational cost, flexibility, and reliability. The ramifications of the choice of a particular cavity type, accelerating gradient, repetition rate, beam pulse length, and number of beam recirculations for the linac design are discussed both with respect to the linac itself and to the Pulse Stretcher Ring. The Pulse Stretcher Ring concept is analysed in terms of injection schemes (single or multi-turn), extraction methods (half or third integer, chromatic or achromatic), and operation parameters (machine tune and chromaticity).