120207704
Design of a high-brightness, high-duty factor photocathode electron gun
Abstract The proposed UV-FEL user's facility at Brookhaven National Laboratory will require a phatocathode gun capable of producing short ( ps ) bunches of electrons at high repetition rates (5 kHz), low energy spread ( ), a peak current of 300 A (after compression) and a total bunch charge of up to 2 nC. At the highest charge, the normalized transverse emittance should be less than 7π mm mrad. We are presently designing a gun that is expected to exceed these requirements. This gun will consist of 3 1 2 cells, constructed of GlidCop-15, an aluminum oxide dispersion strengthened copper alloy. The gun will be capable of operating at duty factors in excess of 1%. Extensive beam dynamics studies of the gun were used to determine the effect of varying the length of the first cell, shaping the apertures between cells, and increasing the number of cells. In addition, a detailed thermal and mechanical study of the gun was performed to ensure that the thermal stresses were well within the allowable limits and that copper erosion of the water channels would not occur.
118755074
Design and construction of a Compact Infrared Free Electron Laser CIRFEL
The 5-15 micron Grumman Compact Infra Red Free Electron Laser CIRFEL which will produce extremely short pulses of tunable radiation under construction is described. Electron pulses are produced at a repetition rate of up to 10 Hz by the illumination of a single crystal <001> LaB/sub 6/ photocathode with a photon injector, a 6-10 psec, 349 nm (frequency tripled Nd-YLF) laser mode locked to the 20th subharmonic of 2856 MHz. Photoelectrons are further accelerated and guided to the superconducting microwiggler by a robust beam transport system through an achromatic bend. The /spl sim/10 MeV electrons interact with the optical radiation inside a near symmetric laser cavity. The FEL output will be coupled out through a hole in one of the cavity mirrors. The CIRFEL system is expected to be delivered in 1994.<<ETX>>
56413579
A superconducting short period undulator for a harmonic generation FEL experiment
A three stage superconducting (SC) undulator for a high gain harmonic generation (HGE) FEL experiment in the infrared is under construction at the NSLS in collaboration with Grumman Corporation. A novel undulator technology suitable for short period (6-40 mm) undulators will be employed for all three stages, the modulator, the dispersive section and the radiator. The undulator triples the frequency of a 10.4 /spl mu/m CO/sub 2/ seed laser. So far a 27 period (one third of the final radiator) prototype radiator has been designed, built and tested.<<ETX>>
23685363
The future of the Large Hadron Collider and CERN
This paper presents the Large Hadron Collider (LHC) and its current scientific programme and outlines options for high-energy colliders at the energy frontier for the years to come. The immediate plans include the exploitation of the LHC at its design luminosity and energy, as well as upgrades to the LHC and its injectors. This may be followed by a linear electron–positron collider, based on the technology being developed by the Compact Linear Collider and the International Linear Collider collaborations, or by a high-energy electron–proton machine. This contribution describes the past, present and future directions, all of which have a unique value to add to experimental particle physics, and concludes by outlining key messages for the way forward.
118687763
The Future of the CERN Accelerator Complex
This chapter looks back at some of the most memorable achievements in high-energy physics during the 50 years spanning CERN's PS and LHC.
110213019
A fast track trigger processor for the opal detector at LEP
Abstract A fast hardware track trigger processor being built for the OPAL experiment is described. The processor will analyse data from the central drift chambers of OPAL to determine whether any tracks come from the interaction region, and thereby eliminate background events. The processor will find tracks over a large angular range, |cos θ | ≲ 0.95. The design of the processor is described, together with a brief account of its hardware implementation for OPAL. The results of feasibility studies are also presented.
117047844
Results from Doris: Neutral detector
The apparatus of the DESY‐Heidelberg group is described. Preliminary results of a recent data evaluation are presented. In the investigation of the two photon cascade ψ′ (3.7) →γ+Pc, Pc→γ+J/ψ (3.1) about 60 events are found with J/ψ→μ+μ− or e+e−. The angular distributions of the γ‐Rays with respect to the beam axis indicate that the intermediate state Pc has non‐zero spin and the mass M(Pc) =3.51±0.02) GeV, while the solution M(Pc) =3.26 GeV seems to be excluded. From a study of total neutral decays of J/ψ (3.1) an upper limit of 1.2% for the neutral radiative decays is obtained.