118704913
NLC Electron Injector Beam Dynamics
The Next Linear Collider (NLC) being designed at SLAC requires a train of 90 electron bunches 1.4 ns apart at 120 Hz. The intensity and emittance required at the interaction point, and the various machine systems between the injector and the IP determine the beam requirements from the injector. The style of injector chosen for the NLC is driven by the fact that the production of polarized electrons at the IP is a must. Based on the successful operation of the SLC polarized electron source, a similar type of injector with a DC gun and subharmonic bunching system is chosen for the NLC.
42734730
Portable, X-Band, Linear Accelerator Systems
Three light-weight, x-band, electron accelerators have been developed to provide a series of highly portable sources of x-rays and neutrons for nondestructive testing. The 1.5 MeV x-ray unit has a 200 kW magnetron for an RF source and an air-cooled, traveling wave accelerating structure to minimize Its weight. The 4 and 6 MeV units share the same drive system which contains a 1.2 MW magnetron. The 4 MeV unit uses a traveling-wave guide to produce x-rays and the 6MeV unit uses a standing-wave guide to produce x-rays or neutrons. The choice of 9.3 GHz was dictated by the availability of a high power coaxial magnetron and by the obvious dimensional and weight advantages of a higher frequency over the more common S-band frequencies around 3 GHz.
124416371
CTF3 Drive-Beam Injector Design
The Two-Beam Accelerator concept is one of the most promising methods for producing RF power for future linear colliders. In particular it allows upgrades to multiTeV energies. One of its challenges is the production of the high current drive beam, which as it passes through decelerating structures, produces RF power for acceleration of the main beam. These challenges must be studied at a smaller scale test facility.
17815790
Polarized electron sources for linear colliders
Linear colliders require high peak current beams with low duty factors. Several methods to produce polarized e{sup {minus}} beams for accelerators have been developed. The SLC, the first linear collider, utilizes a photocathode gun with a GaAs cathode. Although photocathode sources are probably the only practical alternative for the next generation of linear colliders, several problems remain to be solved, including high voltage breakdown which poisons the cathode, charge limitations that are associated with the condition of the semiconductor cathode, and a relatively low polarization of {le}5O%. Methods to solve or at least greatly reduce the impact of each of these problems are at hand.
36965886
A traveling wave accelerator with HOM outcouplers for FELs
The application to FELs (free-electron lasers) of RF electron guns with laser-driven photocathodes has opened the door to developing efficient optical FELs. The next task is to develop accelerator structures which can transport such beams with a minimum of beam degradation. A low-cost approach to this using four 1.26-m constant gradient (CG) TW sections driven in parallel by a SLAC 5045 klystron is suggested. Using CG sections makes the higher order modes incoherent due to the linearly decreasing group velocity along the structure. Together with incorporating higher-order-mode outcouplers, this system is predicted to accelerate 1 nC per micropulse, 0.4 A per macropulse to 75 MeV from an injection energy of 5 MeV. Emittance growth is predicted to be 5 mm-mr.<<ETX>>
54003178
A source of highly polarized electrons at the stanford linear accelerator center
Abstract A polarized electron source based upon photoionization of a state-selected 6 Li atomic beam has been developed as an injection gun for the Standford two-mile electron linear accelerator. The source (PEGGY) produces a pulsed beam of electrons with a maximum intensity of 2.6×10 9 electrons per pulse, a polarization of 0.85, a pulse length of 1.6 μs, and a repitition rate of 180 pulses/s. Since its installation at SLAC in July 1974, PEGGY has been used in several energy electron-nucleon scattering experiments.
125417837
New Geometry of Muon Walls in October 1997 Tilecal Beam Test
Computer controlled positioning system of muon walls is described. Suitable setting for the leakage detection during the extended barrel module 0 beam test is explained in details.
121210133
Inclusive production of charged and neutral sigma hyperons in K−p interactions at 14.3 GeV/c
Abstract Inclusive production of Σ + , Σ − and Σ 0 hyperons in K − p interactions at 14.3 GeV/ c has been studied and compared to Λ production. Cross sections are presented as a function of longitudinal and transverse momenta and compared to the pp → Σ + + anything data.
116422220
A Measurement of K0(L) --> pi+ pi- pi0 Decay Parameters
The decay ${K}_{L}^{0}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{0}$ has been studied in an experiment using the Argonne 12-ft hydrogen bubble chamber exposed to a ${K}_{L}^{0}$ beam of momentum 550 \ifmmode\pm\else\textpm\fi{} 35 MeV/c. After radiative corrections to the data, a fit using a matrix element of the form ${|M|}^{2}\ensuremath{\propto}1+\frac{g({s}_{3}\ensuremath{-}{s}_{0})}{{{m}_{{\ensuremath{\pi}}^{+}}}^{2}}+h{[\frac{({s}_{3} \ensuremath{-} {s}_{0})}{{{m}_{{\ensuremath{\pi}}^{+}}}^{2}}]}^{2} + k{[\frac{({s}_{1} \ensuremath{-} {s}_{2})}{{{m}_{{\ensuremath{\pi}}^{+}}}^{2}}]}^{2}$ gives $g = 0.681\ifmmode\pm\else\textpm\fi{}0.24$, $h = 0.095\ifmmode\pm\else\textpm\fi{}0.032$, and $k = 0.024\ifmmode\pm\else\textpm\fi{}0.010$. The branching ratio $\frac{\ensuremath{\Gamma}({K}_{L}^{0}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{0})}{\ensuremath{\Gamma}({K}_{L}^{0}\ensuremath{\rightarrow}\mathrm{charged})}$ was measured to be 0.163 \ifmmode\pm\else\textpm\fi{} 0.003. These results, when compared to those obtained in other ${K}_{L}^{0}$ and ${K}^{\ifmmode\pm\else\textpm\fi{}}$ decay experiments, indicate a substantial $\ensuremath{\Delta}g\frac{1}{2}$ contribution to the ${K}_{L}^{0}$ decay amplitude.
21235770
Pore morphologies in disordered nanoporous thin films.
Materials with nanometer size heterogeneities are commonplace in the chemical and biological sciences (e.g, polymer blends, microemulsions, gels) and often exhibit complex morphologies. Although this morphology has a dramatic effect on the materials' properties, it is often difficult to accurately characterize. We describe a method, using small-angle X-ray scattering data, of generating representative three-dimensional morphologies of isotropic two-phase materials where the morphology is disordered, and we apply this to thin films containing nanometer sized pores with a range of porosities (4-44%). These representations provide a visualization of the pore morphology, give the pore size scale and extent of interconnection, and permit the determination of the transitions from closed pore to interconnected pores to bicontinuous morphology.
122509981
Search for direct electron production in p-p and p-Be collisions at 12 GeV/c
We have made a systematic search for direct e/sup +/ and e/sup -/ production in p-p and p-Be collisions at 12 GeV/c incident proton momentum. Data were collected at c.m. angles of 20/sup 0/, 35/sup 0/, 63/sup 0/, and 84/sup 0/. We find no evidence for the previously reported rise in the ratio e/..pi.. at low momentum transfer. The data are consistent with zero direct electron production from other than previously known sources.