121259350
Pulsed Heavy Ion Source for the Bevatron
A Phillips ion gauge source (Fig. 1) of the type used by the heavy ion accelerator in Berkeley has been adapted for use at the Bevatron. The objective was to achieve high charge state ions (4+, 5+) of carbon and nitrogen. All source parameters are pulsed. The ion source performance regarding linac acceleration is discussed. The light ion (deuteron, alpha) performance of the PIG source and duoplasmatron is compared.
40263937
Heavy Ion Source Development at the Bevatron
The Bevatron 20 MeV duoplasmatron source is currently being modified with the goal of producing 1 mA of 20Ne3+. Initital tests at 420 KeV show a total beam of 20 mA of which 400 ¿A is 20Ne3+. The quantity of beam in various charge states is determined with a pulse field magnetic spectrometer. Titanium sublimation and cryogenic pumping of the PIG source in the High Voltage Terminal and its resultant effects on the acceleration of carbon and nitrogen will be discussed.
122734759
Measurement and Optimization of the Emittance of a 300-ns 250-A 3.4-MeV Electron Beam
Author(s): Allison, R.W.; Beal, J.W.; Everett, W.L.; Guggemos, J.R.; Lamb, W.A.S.; Richter, R.M.; Sherwood, W.A.; Spoerlein, R.L.; Tanabe, J.; Wright, R.E.; Zajec, E.
6594228
Scattering of gauge, matter, and moduli fields from intersecting branes
Abstract We calculate various tree-level (disk) scattering amplitudes involving gauge, matter and moduli fields in IIB toroidal orbifold/orientifold backgrounds with D9-, D5- respectively D7-, D3-branes or via T -duality D6-branes in type IIA compactifications. In type IIB the D-branes may have non-vanishing fluxes on their world-volume. From these results we extract the moduli and flux dependence of the tree-level gauge couplings, the metrics for the moduli and matter fields. The non-vanishing fluxes correspond in the T -dual type IIA description to intersecting D6-branes. This allows us to determine the moduli dependence of the tree-level matter field metrics in the effective action of intersecting D6-brane models. In addition we derive the physical Yukawa couplings with their correct normalization.
19809846
Development of Fast High-Resolution Muon Drift-Tube Detectors for High Counting Rates
Abstract Pressurized drift-tube chambers are efficient detectors for high-precision tracking over large areas. The Monitored Drift-Tube (MDT) chambers of the muon spectrometer of the ATLAS detector at the Large Hadron Collider (LHC) reach a spatial resolution of 35 μ m and almost 100% tracking efficiency with 6 layers of 30 mm diameter drift tubes operated with an Ar:CO 2 (93:7) gas mixture at 3 bar and a gas gain of 20 000. The ATLAS MDT chambers are designed to cope with background counting rates due to neutrons and γ rays of up to about 300 kHz per tube which will be exceeded for LHC luminosities larger than the design value of 10 34  cm −1  s −1 . Decreasing the drift-tube diameter to 15 mm while keeping the other parameters, including the gas gain, unchanged reduces the maximum drift time from about 700 to 200 ns and the drift-tube occupancy by a factor of 7. New drift-tube chambers for the endcap regions of the ATLAS muon spectrometer have been designed. A prototype chamber consisting of 12 times 8 layers of 15 mm diameter drift tubes of 1 m length has been constructed with a sense wire positioning accuracy of 20 μ m . The 15 mm diameter drift-tubes have been tested with cosmic rays in the Gamma Irradiation Facility at CERN at γ counting rates of up to 1.85 MHz.
121506437
Gluing silicon with silicone
Abstract Problems and solutions concerning the gluing of silicon detectors are discussed. The R & D work for the HERA- B vertex detector system led to gluing studies with epoxy and silicone-based adhesives used on ceramics and carbon fibre. The HERA- B solution using a silicone glue is presented.
37514459
A Flash ADC System for TPC Readout
We present the outline of a data taking system that uses waveform recording for 50,000 electronic channels. This system will be used for the readout of a Time Projection Chamber which serves as the central detector of the ALEPH experiment at LIP. The requirements of the digitizing system are discussed, together with the problem of data reduction.
122666349
Ion trapping properties of a synchronously gated time projection chamber
Abstract Studies have been made of the transmission of positive ions through the gating grid of a time projection chamber operated synchronously at a high rate. With a duty cycle of 25% (22 μs periodic wave form) it has been demonstrated that less than one positive ion in 7 × 10 −3 traverses the gating grid. This new gating technique can be used by a time projection chamber operating at the LEP e + e − collider.