3128292
Lattice design of Beijing Light Source
In this paper, the preliminary design of the magnet lattice of the Beijing Light Source (BLS) is described. The Beijing Light Source is a new generation light source with the energy of 2.2 GeV-2.5 GeV. By choosing the FBA (five bend achromat) and TBA (triplet bend achromat) structure very low horizontal emittance is reached using superconducting dipole magnets. Having made some harmonic corrections, an acceptable dynamic aperture is obtained though further improvement is being done to enlarge the horizontal aperture.
56470793
DESIGN OF BEAM TRANSPORT LINE FROM RCS TO TARGET FOR CSNS
China Spallation Neutron Source (CSNS) uses the high energy proton beam to strike the Tungsten target to generate neutrons through spallation reaction. The proton beam is extracted from the Rapid Cycling Synchrotron (RCS), whose beam power reaches 100 kW. For the sake of target lifetime, beam distribution at the target surface is required as uniform as possible. Nonlinear beam density redistribution method with two octupole magnets has been studied. Also some simulation and theoretical calculation have been done. According to the simulation result, the beam density at the target is optimized and the beam loss is under control.
55843797
LATTICE DESIGN FOR THE BEPCII STORAGE RING
BEPCII, the upgrading project of the BEPC, has been being designed with a luminosity of 10 33 cm -2 s -1 at the J/ψ energy. It still keeps the potential to provide beams as a synchrotron radiation (SR) facility. The storage rings for collision contain a positron and an electron ring and the ring for dedicated SR uses the outer parts of the two rings. To fit all the conditions either on beam or on space limit, lattices are carefully designed for both high energy physics and SR experiments with sufficient dynamic apertures and high efficiencies for injection. The features of the lattices are also discussed in the paper. 1 DESIGN REQUIREMENTS BEPCII is an upgrade project of the Beijing ElectronPositron Collider (BEPC), in which a new inner ring will be installed inside the old one. It will provide colliding beams with the center-of-mass energy from 1.0GeV×2 to 2.0GeV×2 and also the dedicated synchrotron radiation beam with 2.5 GeV. For the colliding beams the luminosity is optimized at 1.89 GeV with 1×10 33 cm -2 s -1 . For the dedicated synchrotron radiation beam, the current is 250 mA with an emittance as low as possible. There have been several beam-lines in the BEPC for the synchrotron radiation experiments, so the current bending magnets and insertion devices in the southern region have to be fixed at their present positions. In order to increase the average luminosity, the “topoff” injection scheme up to 1.89 GeV is adopted. This requires that the injection and collision optics must be the same. The main parameters are shown in Tables 1 and 2.
123594822
Transfer matrices of dipoles with bending radius variation
With the increasing demand of high brightness in light source, the uniform dipole can not meet the needs of low emittance, and thus the dipole with bending radius variation is introduced in this paper. The transfer matrix of a non-uniform dipole whose bending radius is linearly changed is chosen as an example and a very simple calculation formula of non-uniform dipole transfer matrices is given. The transfer matrices of some common profile non-uniform dipoles are also listed. The comparison of these transfer matrices and the matrices calculated with slices method verifies the numerical accuracy of this formula. This method can make the non-uniform beam dynamic problem simpler, very helpful for emittance research and lattice design with non-uniform dipoles.
124075894
General conditions for self-cancellation of geometric aberrations in a lattice structure
In this paper we will discuss the general conditions for self-cancellation of geometric aberrations in an uncoupled or even coupled lattice structure. The self-cancellation conditions show that - I transformer even noninterleaved multipoles is not necessary. We will also give two examples for sextupole case to specify the application.
60626146
ILC Reference Design Report: ILC Global Design Effort and World Wide Study
124457067
Search for Invisible Decays of eta and eta-prime in the Processes J/psi ---> phi eta and phi eta-prime
Using a data sample of 58x10{sup 6} J/{psi} decays collected with the Beijing Spectrometer II detector at the Beijing Electron Positron Collider, searches for invisible decays of {eta} and {eta}{sup '} in J/{psi} to {phi}{eta} and {phi}{eta}{sup '} are performed. The {phi} signals, which are reconstructed in K{sup +}K{sup -} final states, are used to tag the {eta} and {eta}{sup '} decays. No signals are found for the invisible decays of either {eta} or {eta}{sup '}, and upper limits at the 90% confidence level are determined to be 1.65x10{sup -3} for the ratio (B({eta}{yields}invisible)/B({eta}{yields}{gamma}{gamma})) and 6.69x10{sup -2} for (B({eta}{sup '}{yields}invisible)/B({eta}{sup '}{yields}{gamma}{gamma})). These are the first searches for {eta} and {eta}{sup '} decays into invisible final states.
6707114
Detection of Cherenkov light emission in liquid argon
Detection of Cherenkov light emission in liquid argon has been obtained with an ICARUS prototype, during a dedicated test run at the Gran Sasso Laboratory external facility. Ionizing tracks from cosmic ray muons crossing the detector active volume have been collected in coincidence with visible light signals from a photo-multiplier (PMT) immersed in liquid argon. A 3D reconstruction of the tracks has been performed exploiting the ICARUS imaging capability. The angular distributions of the tracks triggered by the PMT signals show an evident directionality. By means of a detailed Monte Carlo simulation we show that the geometrical characteristics of the events are compatible with the hypothesis of Cherenkov light emission as the main source of the PMT signals.
123128473
On the systematic behaviour of the intermittency-indices in nuclear interactions
M.I. Adamovich a, M.M. Aggarwal b, Y.A. Alexandrov a, N.P. Andreeva c, Z.V. Anson c, R. Arora b, F.A. Avetyan d, S.K. Badyal e, E. Basova f, K.B. Bhalla g, A. Bhasin e, V.S. Bhatia b, V.G. Bogdanov h, V.I. Bubnov c, T.H. Burnett i, X. Cai J, I.Y. Chasnikov c, L.P. Chernova k, M.M. Chernyavski a, B. Dressel ~, G.Z. Eligbaeva c, L.E. Eremenko ~, E.M. Friedlander m, A.S. Gaitinov ~, E.R. Ganssauge ~, S. Garpman ", S.G. Gerassimov a, j. Grote i, K.G. Gulamov k, S.K. Gupta g, V. Gupta e, H.H. Heckrnan ~, H. Huang J, B. Jakobsson ", B. Judek o, S. Kachroo e, F.G. Kadyrov k, G.S. Kalyachkina c, E.K. Kanygina ~, M. Karabova P, G.L. Kaul e, M. Kaur b, S.P. Kharlamov a, T. Koss i, S.A. Krasnov P, V. Kumar g, P. Lal g, V.G. Larionova a, V.N. Lepetan ~, P.J. Lindstrom m, L.S. Liu J, S. Lokanathan g, J. Lord i, N.S. Lukicheva k, S.B. Luo q, L.K. Mangotra e, N.A. Marutyan d, N.V. Maslennikova ", I.S. Mittra b, S. Mookerjee g, C. Mueller ~, H. Nasrulaeva f, S.H. Nasyrov f, V.S. Navotny k, G.I. Orlova a, I. Otterlund n, H.S. Palsania g, N.G. Peresadko a, N.V. Petrov f, V.A. Plyushchev h, W.Y. Qian J, R. Raniwala g, S. Raniwala g, N.K. Rao ~, V.M. Rappoport a, J.T. Rhee ~, N. Saidkhanov k, N.A. Salmanova ~, L.G. Sarkisova d, V.R. Sarkisyan d, W. Schulz ~, G.S. Shabratova P, T.I. Shakhova ~, B. Singh b, D. Skelding i, K. SSderstrSm ", Z.I. Solovjeva h, E. Stenlund n, S.C. Strausz i, J.F. Sun r, L.N. Svechnikova k, K.D. Tolstov P, M.I. Tretyakova a, T.P. Trofimova r, U. Tuleeva r, S. Vokal P, H.Q. Wang J, Z.Q. Weng r, R.J. Wilkes i, G.F. Xu s, D.H. Zhang q, P.Y. Zheng s, S.I. Zhochova k, D.C. Zhou J and J.C. Zhou J
110626236
Tests of MVD prototype pad detector with a β- source
Abstract The MVD group has been testing two versions of silicon pad detectors. One design uses a single metal layer for readout trace routing. The second type uses two layers of metal, allowing for greatly simplified signal routing. However, because the readout traces for the pads pass over the other pads in the same column (separated by an oxide layer), the double-metal design introduces crosstalk into the system. A simple test stand using a 90 Sr β − source with scintillator triggers was made to estimate the crosstalk. The crosstalk between pads in the same column of the pad detector was 1.6–3.1%. The values measured between pads in different columns were very close to zero. The measured crosstalk was below our maximum allowed value of 7.8%.
10335512
Antilambda production in Au+Au collisions at 11.7A GeV/c.
We present results for antilambda and antiproton production in Au+Au collisions at 11.7 A GeV/c including spectra and extracted invariant yields for both species in central and peripheral collisions in the rapidity range 1.0<y<1.4. The antilambda yield increases from dN(Lambda;)/dy = 1.2(+0.7+0.2)(-0.6-0.2)x10(-3) in peripheral collisions to 19(+4+3)(-5-2)x10(-3) in central collisions. The direct antiproton yield is deduced from the measured total antiproton spectra to extract the ratio of antilambda-to-direct-antiproton production. The Lambda/p ratio near midrapidity increases from 0.26(+0.19+0.5)(-0.15-0.4) in peripheral collisions to 3.6(+4.7+2.7)(-1.8-1.1) in central collisions, a value larger than current theoretical estimates.