[en] A one-day workshop was held on July 21st, 1998 to consider upgrade paths to the existing LCLS design with a view to making a facility with multiple FEL and spontaneous synchrotron radiation beamlines. The agenda, working groups and participants in this workshop are listed in Appendix 1. This technical note summarizes the ideas generated by this workshop

[en] The Linac Coherent Light Source (LCLS) project at the Stanford Linear Accelerator Center (SLAC) will produce intense, coherent 0.15 nm x-rays, with an expected peak brightness many orders of magnitude greater than existing x-ray sources and energy density as high as 4 x 10²⁵ watts/cm². These x-rays are produced by a single pass of a 15 GeV electron beam through a long undulator. The 15 GeV electron beam is generated using the last one third of the existing SLAC linac. This paper describes how to extend the present design of the LCLS to generate even shorter x-ray pulses than the nominal 255 femtoseconds FWHM. The goal of this study is to obtain pulse lengths as short as 50 femtoseconds. The scientific need for the shorter bunches is outlined, and electron and x-ray pulse compression options are reviewed. The analysis concludes that there are paths, albeit difficult, to obtaining shorter bunches and that the present LCLS design has the flexibility and range to test these paths

[en] A conventional positron source for the ILC using a very long macro-pulse for the electron drive beam is proposed. In comparison with an undulator based positron source, a conventional positron source decouples positron production from the main linac electron beam, leading to faster commissioning and improved positron system up-time. Of the 200 ms in between ILC pulse trains, 100 ms will be used to make positrons. While this will make the positron target design easier, it will require the electron drive, positron capture linacs and the adiabatic matching device to run at 50% duty cycle or more and a pre-damping ring with sufficient damping power to prepare the beam for injection into the damping ring in 100 ms

[en] Using the accelerator data collected during the 1988-1989 collider run, correlations have been established between the proton-antiproton collider luminosity, the antiproton stack intensity and the proton bunch parameters. These correlations are used to determine empirically the value of the proton transverse emittance which maximizes the collider luminosity. Also, the correlations are used to predict the effects of planned improvements in collider subsystem performance in the luminosity. 2 refs., 1 fig., 1 tab

[en] The Tevatron Collider at Fermilab is the world's highest energy hadron collider, colliding protons with antiprotons at a center of mass energy of 1800 GeV. At present six proton bunches collide with six antiproton bunches to generate luminosities of up to 9 x 10³⁰ cm^-2s^-1. It is estimated that to reach luminosities significantly greater than 10³¹ cm^-2s^-1 while minimizing the number of interactions per crossing, the number of bunches will have to be increased. Thirty-six bunch operation looks like the most promising plan. This paper looks at the strategies for increasing the number of particle bunches, the new hardware that needs to be designed and changes to the operating mode in filling the Tevatron. An interactive program which simulates the filling of the Tevatron collider is also presented. The time scale for multibunch operation and progress towards running greater than six bunches is given in this paper

[en] We have measured the cross-section for the exclusive reaction, ¹²C(ν/sub e/,e/sup /minus//)¹²N(g.s.). The experiment was performed with a 15 ton fine-grained tracking detector exposed to ν/sub e/'s with equivalent energy of 37 MeV. The detector was triggered by single electrons and the exclusive inverse-beta reaction identified by the delayed coincidence of the ¹²N(gs) positron-decay. The flux averaged cross-section was measured to be [1.18 +- 0.11(stat) +- 0.13(sys)] /times/ 10/sup /minus/41/ cm². This result is compared to recent calculations. 3 refs., 1 fig

[en] A unique method of spectroscopy has been successfully employed by experiment 760 at Fermilab resulting in data of unprecedented accuracy. A general survey of the experiment as well as the data results which are presently available from the experiment on reaction of the type pantip->cantic is presented

[en] The Fermilab antiprotron Accumulator has been modified for use in a medium energy experiment. The experiment is conducted with circulating antiproton beam of momentum between 6.7 GeV/c and 3.7 GeV/c colliding with protons from an internal gas jet. Antiprotons are accumulated at the normal momentum of 8.9 GeV/c and then decelerated to the appropriate energy. It is necessary to cool the beam continually during the time it is colliding with the gas jet. The experiment requires new provisions for the control of magnet power supplies and low level rf system and modifications of the cooling system and high level energy systems to permit variable energy operation. Transition must be crossed to decelerate the beam below 5 GeV/c; because the deceleration is very slow, transition can not be crossed in a conventional manner. This paper will describe the required changes to the Accumulator and operating experience with protons. 8 refs., 2 figs., 1 tab

[en] We present preliminary results of a neutrino experiment in progress at LAMPF by an Irvine-Los Alamos-Maryland collaboration. We have observed a signal consistent with nu/sub e/e^- elastic scattering, with a 15-ton sandwich detector. The number of these nu/sub e/e^- candidates agrees with that predicted by the Weinberg-Salam electroweak theory. The corresponding sin²theta/sub w/ and total cross section are reported. This study shows that the interference of weak charged-current and weak neutral-current in nu/sub e/e^- scattering is not constructive. We also searched for anomalous appearance of anti nu/sub e/ from the LAMPF beam stop. An upper limit for the multiplicative lepton number conservation law, and limits for anti nu/sub μ/ → anti nu/sub e/ oscillation are given. 15 references

[en] In the International Linear Collider (ILC) positron source, multi-GeV electrons or multi-MeV photons impinge on a metal target to produce the needed positrons in the resulting electromagnetic showers. The incoming beam power is hundreds of kilowatts. Various computer programs--such as FLUKA or MARS--can calculate how the incoming beam showers in the target and can track the particle showers through the positron source system. Most of the incoming energy ends up as heat in the various positron source elements. This paper presents results from such calculations and their impact on the design of a positron source for the ILC