A. Van Ginneken

Energy loss and angular characteristics of high energy electromagnetic processes

Abstract For high energy protons, pions and muons (up to 30 TeV) the energy and angle of the final state particles in bremsstrahlung, direct pair production and, for muons, deep inelastic scattering are determined as a function of the fractional energy loss of the incident particle. The results are parametrized for convenient use in Monte Carlo simulations. The average energy loss and rms angular deflection of muons, pions and protons in bulk matter are determined and compared with other work.

Target and Collection Optimization for Muon Colliders

To achieve adequate luminosity in a muon collider it is necessary to produce and collect large numbers of muons. The basic method used in this paper follows closely a proposed scheme which starts with a proton beam impinging on a thick target ({approximately} one interaction length) followed by a long solenoid which collects muons resulting mainly from pion decay. Production and collection of pions and their decay muons must be optimized while keeping in mind limitations of target integrity and of the technology of magnets and cavities. Results of extensive simulations for 8 GeV protons on various targets and with various collection schemes are reported. Besides muon yields results include-energy deposition in target and solenoid to address cooling requirements for these systems. Target composition, diameter, and length are varied in this study as well as the configuration and field strengths of the solenoid channel. A curved solenoid field is introduced to separate positive and negative pions within a few meters of the target. This permits each to be placed in separate RF buckets for acceleration which effectively doubles the number of muons per bunch available for collisions and increases the luminosity fourfold.

Calculation of antiproton yields for the fermilab antiproton source

Abstract The available experimental data for antiproton production are described by an analytical formula, including target nucleus dependence. This formula, in conjunction with a Monte Carlo program that includes the effect of hadronic showers, is used to optimize the design of the Fermilab Antiproton Source. Comparison is made with measurements of yields at the CERN Antiproton Accumulator.

Fluctuations of muon energy loss and simulation of ionization cooling

A Monte Carlo program to simulate muon ionization cooling is outlined. A Vavilov-type distribution to represent restricted ionization energy losses is derived. Above the restriction threshold μe scattering is treated event-by-event. Likewise μ-nucleus elastic scattering is simulated by a Gaussian below some angular threshold and treated individually above it. Other processes included are: incoherent μp scattering with nuclear protons, bremsstrahlung, pair production, and deep inelastic nuclear scattering. A small sample of results obtained with the code is included.

Edgeworth series for collision energy loss and multiple scattering

Abstract The Edgeworth expansion is used to go beyond the usual Gaussian approximation for collision energy loss and multiple scattering. Monte Carlo algorithms based on the expansion are presented. Comparisons of the Edgeworth expansion with exact results of Vavilov and Moliere are shown. A simple model which attempts to include correlations between energy loss and angular distribution is proposed and illustrated with an example.

Measurements and calculations of cascades produced by 300 GeV protons incident on a target inside a magnet

Abstract A thick aluminum block placed between the pole pieces of a magnet was irradiated with 300 GeV protons. Responses of activation foils and dosimeters placed around the magnet and inside the gap were measured to study the propagation of high-energy cascades. Predictions of two different Monte Carlo calculations agree well with these measurements.

Neutrino radiation at muon colliders and storage rings

Intense highly collimated neutrino beams, created from muon decays at high-energy muon colliders or storage rings, cause significant radiation problems even at very large distances from the machine. A recently developed weighted neutrino interaction generator permits detailed Monte Carlo simulations of the interactions of neutrinos and of their progeny with the MARS code. Special aspects of neutrino radiation dose evaluation are discussed. Dose distributions in a tissue-equivalent phantom are calculated when irradiated with 100 MeV to 10 TeV neutrino beams. Results are obtained for a bare phantom, one embedded in several shielding materials, and one located at various distances behind a shield. Neutrino radiation is investigated around muon storage rings serving as the basis for neutrino factories. The most challenging problem of off-site neutrino dose from muon colliders and storage rings is studied. The distance from the collider ring (up to 60 km) at which the expected dose rates equals prescribed annual dose limits is calculated for 0.5-4 TeV muon colliders and 30 and 50 GeV muon storage rings. Possible mitigation of neutrino radiation problems are discussed and investigated.

Pion production and targetry at μ+μ− colliders

Results of simulations of pion production and power dissipation by 8 to 30 GeV proton beams in co-axial and tilted targets of liquid gallium and platinum oxide, placed in a 20 T solenoid, are reported. Pion and muon distributions are followed through the matching solenoid and decay channel.Results of simulations of pion production and power dissipation by 8 to 30 GeV proton beams in co-axial and tilted targets of liquid gallium and platinum oxide, placed in a 20 T solenoid, are reported. Pion and muon distributions are followed through the matching solenoid and decay channel. {copyright} {ital 1998 American Institute of Physics.}

Ring cooler for muon collider

The possibilities of a ring cooler stage in a muon collider are explored. A basic design is examined both with analytic calculations and simulation of the evolution of beam phase space.

Muons and Neutrinos at High-Energy Accelerators

Background levels in detectors and radiation problems at future colliders--whether pp, e{sup +}e{sup {minus}} or {mu}{sup +}{mu}{sup {minus}} are in large part determined by the presence of muons. Neutrinos from muon decay at muon colliders or storage rings are highly collimated and propagate outward within a narrowdisk in which significant radiation doses persist out to very large distances. This paper highlights physics models and Monte Carlo algorithms developed mainly for studying these problems as well as some typical results.