| 1. |
- Alcorn, J, et al.
(författare)
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Basic instrumentation for Hall A at Jefferson Lab
- 2004
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - : Elsevier BV. - 0167-5087 .- 0168-9002. ; 522:3, s. 294-346
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Tidskriftsartikel (refereegranskat)abstract
- The instrumentation in Hall A at the Thomas Jefferson National Accelerator Facility was designed to study electro-and photo-induced reactions at very high luminosity and good momentum and angular resolution for at least one of the reaction products. The central components of Hall A are two identical high resolution spectrometers, which allow the vertical drift chambers in the focal plane to provide a momentum resolution of better than 2 x 10(-4). A variety of Cherenkov counters, scintillators and lead-glass calorimeters provide excellent particle identification. The facility has been operated successfully at a luminosity well in excess of 10(38) CM-2 s(-1). The research program is aimed at a variety of subjects, including nucleon structure functions, nucleon form factors and properties of the nuclear medium. (C) 2003 Elsevier B.V. All rights reserved.
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| 2. |
- Abt, I, et al.
(författare)
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Measurement of the b(b)over-bar production cross section in 920 GeV fixed-target proton-nucleus collisions
- 2003
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 26:3, s. 345-355
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Tidskriftsartikel (refereegranskat)abstract
- Using the HERA-B detector, the b (b) over bar production cross section has been measured in 920 GeV proton collisions on carbon and titanium targets. The b (b) over bar production was tagged via inclusive bottom quark decays into J/psi by exploiting the longitudinal separation of J/psi --> l(+)l(-) decay vertices from the primary proton-nucleus interaction. Both e(+)e(-) and mu(+)mu(-) channels have been reconstructed and the combined analysis yields the cross section sigma(b (b) over bar) = 32(-12)(+14)(stat) (+6)(-7)(sys) nb/nucleon.
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| 3. |
- Abt, I, et al.
(författare)
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Inclusive V-0 production cross sections from 920 GeV fixed target proton-nucleus collisions
- 2003
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 29:2, s. 181-190
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Tidskriftsartikel (refereegranskat)abstract
- Inclusive differential cross sections dsigma(pA)/dx(F) and dsigma(pA)/dp(t)(2) for the production of K-S(0), Lambda, and (&ULambda;) over bar particles are measured at HERA in proton-induced reactions on C, Al, Ti, and W targets. The incident beam energy is 920 GeV, corresponding to roots = 41.6 GeV in the proton-nucleon system. The ratios of differential cross sections dsigma(pA)(K-S(0))/dsigma(pA)(Lambda) and dsigma(pA)((&ULambda;) over bar)/dsigma(pA) (Lambda) are measured to be 6.2 +/- 0.5 and 0.66 +/- 0.07, respectively, for x(F) approximate to -0.06. No significant dependence upon the target material is observed. Within errors, the slopes of the transverse momentum distributions da,Ald t also show no significant dependence upon the target material. The dependence of the extrapolated total cross sections sigma(pA) on the atomic mass A of the target material is discussed, and the deduced cross sections per nucleon sigma(pN) are compared with results obtained at other energies.
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| 4. |
- Gayou, O, et al.
(författare)
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Measurement of G(Ep)/G(Mp) in (e)over-right-arrowp -> e(p)over-right-arrow to Q(2)=5.6 GeV2
- 2002
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Ingår i: Physical Review Letters. - 1079-7114. ; 88:9
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Tidskriftsartikel (refereegranskat)abstract
- The ratio of the electric and magnetic form factors of the proton G(Ep)/G(Mp), which is an image of its charge and magnetization distributions, was measured at the Thomas Jefferson National Accelerator Facility (JLab) using the recoil polarization technique. The ratio of the form factors is directly proportional to the ratio of the transverse to longitudinal components of the polarization of the recoil proton in the elastic (e) over right arrowp --> e (p) over right arrow reaction. The new data presented span the range 3.5 < Q(2) < 5.6 GeV2 and are well described by a linear Q(2) fit. Also, the ratio rootQ(2) F-2p/F-1p reaches a constant value above Q(2) = 2 GeV2.
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| 5. |
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| 6. |
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| 7. |
- Chen, L., et al.
(författare)
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Process development and reliability for system-in-a-package using liquid crystal polymer substrate
- 2004
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Ingår i: Proc Electron Compon Technol Conf. ; , s. 24-28
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Konferensbidrag (refereegranskat)abstract
- In this study, embedded chip technology for system-in-a-package (SiP) application using liquid crystal polymer (LCP) substrate was developed and the reliability issue for embedded structure was evaluated. To this end two test chips with daisy chain joints were used with one copper layer. After assembly, modules were exposed to thermal cycling. The failure was investigated by SEM, and compared with finite element method (FEM) simulation results. Passive components as inductors were also fabricated on the LCP during the embedded technology. Their inductance and quality factors were simulated and discussed.
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| 8. |
- Wang, Z, et al.
(författare)
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The boundary phase and the melting of CaSiO3 and MgSiO3 perovskites
- 2000
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Ingår i: Journal of Physics and Chemistry of Solids. - 0022-3697. ; 61:11, s. 1815-1820
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Tidskriftsartikel (refereegranskat)abstract
- We have investigated the melting temperatures of MgSiO3 and CaSiO3 perovskites at high pressure conditions, using an empirical melting equation, combined with the assumption of a boundary phase existing at the melting point. This study indicates that both CaSiO3 and MgSiO3 perovskites have a cubic structure near the melting boundary, and that the obtained melting temperatures are in good agreement with experimental measurements (Zerr et al., Geophys. Res. Lett. 24 (1998) 909; J.S. Sweeney, D.L. Heinz, High Pressure-Temperature Research: Properties of Earth and Planetary Materials, in: M.H. Manghnani, T. Yagi (Eds.), AGU, (1998) p. 185]. Additionally, our results reveal that CaSiO3 and MgSiO3 perovskites cannot cause a partial melting at the core-mantle boundary. Our calculation and assumption suggest that the Lindemann law is valid to estimate the melting temperatures of silicates as the silicate phases near the melting boundary are definitely determined and chosen.
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