D. Carey

The design and performance of the FNAL high-energy polarized beam facility

We describe a new polarized-proton and -antiproton beam with 185-GeV/c momentum in the Fermilab MP beam line which is currently operational. The design uses the parity-conserving decay of lambda and antilambda hyperons to produce polarized protons and antiprotons, respectively. A beam-transport system minimizes depolarization effects and uses a set of 12 dipole magnets that rotate the beam-particle spin direction. A beam-tagging system determines the momentum and polarization of individual beam particles, allowing a selection of particles in definite intervals at momentum and polarization. We measured polarization of the beam by using two types of polarimeters, which verified the determination of polarization by a beam-particle tagging system. Two of these processes are the inverse-Primakoff effect and the Coulomb-nuclear interference (CNI) in elastic proton-proton scattering. Another experiment measured the {pi}{sup 0} production asymmetry of large-x{sub F} values; this process may now be used as an on-line beam polarimeter. 9 refs., 9 figs.

Why a second-order magnetic optical achromat works

Abstract A design procedure for a charged particle optical system where all second order matrix elements can be made to vanish simultaneously. has been described by Brown [1]. The symmetry of the system requires all geometric second-order matrix elements to vanish. A proof is given that all chromatic second-order matrix elements will also vanish.

Forward Neutron Production at the Fermilab Main Injector

We have measured cross sections for forward neutron production from a variety of targets using proton beams from the Fermilab Main Injector. Measurements were performed for proton beam momenta of 58, 84, and 120 GeV/c. The cross section dependence on the atomic weight (A) of the targets was found to vary as A{sup {alpha}}, where {alpha} is 0.46{+-}0.06 for a beam momentum of 58 GeV/c and 0.54{+-}0.05 for 120 GeV/c. The cross sections show reasonable agreement with FLUKA and DPMJET Monte Carlos. Comparisons have also been made with the LAQGSM Monte Carlo.

A large liquid argon photon/hadron calorimeter for FNAL

Abstract This paper describes a new liguid argon photon/hadron detector currently under construction for Experiment E706 at the Fermi National Accelerator Laboratory.

High energy charged particle optics computer programs

Abstract The computer programs TRANSPORT and TURTLE are described, with special emphasis on recent developments. TRANSPORT is a general matrix evaluation and fitting program. First and second order transfer matrix elements, including those contributing to time-of-flight differences can be evaluated. Matrix elements of both orders can be fit, separately or simultaneously. Floor coordinates of the beam line may be calculated and included in any fits. Tables of results of misalignments, including effects of bilinear terms can be produced. Fringe fields and pole face rotation angles of bending magnets m be included and also adjusted automatically during the fitting process to produce rectangular magnets. A great variety of output options is available. TURTLE is a Monte Carlo program used to simulate beam line performance. It includes second order terms and aperture constraints. Replacable subroutines allow an unlimited variety of input beam distributions, scattering algorithms, variables which can be histogrammed, and aperture shapes. Histograms of beam loss can also be produced. Rectangular zero-gradient bending magnets with proper circular trajectories, sagitta offsets, pole face rotation angles, and aperture constraints can be included. The effect of multipole components of quadrupoles up to 40 pole can be evaluated.

Charged kaon mass measurement using the Cherenkov effect

The two most recent and precise measurements of the charged kaon mass use X-rays from kaonic atoms and report uncertainties of 14 ppm and 22 ppm yet dier from each other by 122 ppm. We describe the possibility of an independent mass measurement using the measurement of Cherenkov light from a narrow-band beam of kaons, pions, and protons. This technique was demonstrated using data taken opportunistically by the Main Injector Particle Production experiment at Fermi National Accelerator Laboratory which recorded beams of protons, kaons, and pions ranging in momentum from +37 GeV/c to +63 GeV/c. The measured value is 491.3 1.7 MeV/c 2 , which is within 1.4 of the world average. An improvement of two orders of magnitude in precision would make this technique useful for resolving the ambiguity in the X-ray data and may be achievable in a dedicated experiment.

Beamline design for particle production experiment, E907, at FNAL

Experiment 907 at Fermilab will be conducted in the Meson Center beam enclosure. The purpose of this experiment is to measure cross sections for hadron production from nuclear interactions using pions, kaons and proton beams in the momentum range from 5 to 120 GeV/c. Light to heavy targets will be used to study the scaling laws of hadronic fragmentation and light meson and baryon spectroscopy. Design aspects for the experiments beamline are presented. The lattice, in particular the secondary beamline design, the primary target, and the collimation system are covered.

Silicon position sensitive detectors for the Helios (NA 34) experiment

Abstract Silicon detectors having both “pad” and strip position sensitive configurations have been fabricated for the Helios experiment which requires an elaborate pulse height-dependent trigger as well as one dimensional silicon strip position sensing. The trigger detector is a 400 element, 30 mm diameter detector with readout connections from a ceramic overlay board. Tests with full prototype detectors have shown essentially 100% detection efficiency and excellent pulse height resolution well capable of delineating 0, 1 or 2 hits per pad. Strip detectors with 25 μm pitch and a varying readout pitch have been tested, which utilize both capacitive and resistive charge division. Techniques for realization of required interstrip resistors will be discussed and results which may compare these readout methods will be reported.

Performance characteristics and radiation damage results from the Fermilab E706 silicon microstrip detector system

Abstract A charged particle spectrometer containing a 7120-channel silicon microstrip detector system, one component of Fermilab experiment E706 to study direct photon production in hadron-hadron collisions, was utilized in a run in which 6 million events were recorded. We describe the silicon system, provide early results of track and vertex reconstruction, and present data on the radiation damage to the silicon wafers resulting from the narrow high intensity beam.

The effect on the quality of high-energy beams of nonlinearities in the field of magnetic quadrupoles

Abstract Nonlinearities in the field of magnetic quadrupoles will affect the quality of any beam in which they are used. Good field-regions or image-quality determinations can be made by exploring the phase space transmitted by the beam line. The error field of each quadrupole disturbs the trajectory of any particle passing through it. We present an efficient method for approximating the effect of this disturbance. The integral equation of motion is solved approximately by a single Greens function iteration, giving an expression linear in the non-quadrupole terms in the magnetic field. This expression can then be evaluated by a linear approximation to the particle orbits in the quadrupole. The field is decomposed into multipoles, the effects of different orders are generated recursively, and the results are summed to obtain the net disturbance.