Five R&D dipole magnets have been assembled with different levels of tangential prestress applied to the windings. Four magnets have trained beyond the ISABELLE 5T operating field. Three have trained to the short sample limit of the superconducting braid. The two magnets with the highest level of tangential prestress required the fewest training quenches to reach 5T. The training history of these R&D magnets is better than that of the eleven industrial magnets. Two of the industrial magnets were trained beyond 4.5T; the others reached fields in the range 3.8T to 4.2T. The industrial magnets had generally lower levels of prestress than the R&D magnets and differed in other important respects as well. These changes were designed to reduce the heat generated by conductor motion due to Lorentz forces. Construction of magnets with the present design has eliminated the largest part of the training quenches seen in the industrial series of magnets.

This report updates the various designs and prototypes tested since the last Conference. Included are the operational data of a subassembly of the old 200 × 200 GeV machine design as well as the latest larger prototype ring magnets with their strong points and shortcomings. The working line coil system design presently seems to be nearly completed, having gone through major revisions to increase its possible operational range. One of the major design goals of the magnet series, that of each unit being able to absorb their own energy, seems to be well in hand. This feature enables the magnet string to be protected without external intervention, i.e., without external energy dump or driving the magnet winding normal by an active external circuit. Simply stated, this means that the magnet's L/R time constants during quench are short enough to prevent thermal damage. There are two series of prototypes. The first type is the so called "Standard" which will become the ring magnet for ISABELLE. The second is that in which various characteristics and/or limits of various parameters are explored. Various parameters such as specific heat of the windings, increased metal packing fractions, and resistivity of turns (in the normal state) are bracketed. The 400 × 400 GeV version of ISABELLE1 requires acold aperture of 13.09 cm, quadrupole magnetic length of 1.6 m, and dipole length of 4.65 m at a peak dipole field of 5.0 T. Two machine size dipoles and one quadrupole are being presently tested.

Inclusive particle production was measured in neutron-nucleus collisions at high energies. Data on positive and negative particles produced in nuclei, ranging in size from Be to Pb, are presented for essentially the full forward hemisphere of the center of mass. Fits of the form A/sup ..cap alpha../ to the invariant production cross section indicate that ..cap alpha.. changes from approx. 0.85 to approx. 0.55 for laboratory rapidities ranging from 3 to 8. This result is consistent with predictions from multiperipheral models which invoke cut contributions to production in nuclei.

In 1978 the magnetic field shapes of six ISABELLE prototype dipole magnets were measured in detail. All the harmonic terms that are forbidden by symmetry in dipole magnets are found to have values that are zero to within the allowed tolerances. This result indicates that the random errors in conductor placement are within tolerances and that the assembly techniques are satisfactory in this regard....

We have compared our data for nuclear coherent dissociation of neutrons into ($p{\ensuremath{\pi}}^{\ensuremath{-}}$) systems with a production model which was used previously to investigate the nature of the diffractive process on a hydrogen target. The decay and production characteristics observed for ($p{\ensuremath{\pi}}^{\ensuremath{-}}$) systems produced on nuclear targets at Fermilab energies are in qualitative agreement with the predictions of the model.

This report updates the various performance data, design and specifications for the storage ring and experimental series dipole and quadrupole magnets as well as the working line and correction coil systems. The working line system includes the closed orbit dipoles, the quadrupole trim, sextupoles, octapoles, decapoles and duodecapoles. These are the magnets in the standard subunits of the Brookhaven National Laboratory Intersecting Storage Ring Accelerator "ISABELLE". There have been 14 full size single layer dipole prototypes 4.25 to 4.75 m long constructed. There have been two 1.5 m long full size quadrupoles built. A one meter double layer dipole was built in order to obtain high field > 6.0 T data. A subunit of the original 200 × 200 GeV version of the ISABELLE lattice was assembled to study systems operation. (ISABELLE now has the design goal of 400 × 400 GeV.) This subunit utilized the proposed ISABELLE form of refrigeration, namely "high pressure helium gas forced flow". The array composed of two dipoles and a quadrupole with auxiliary working line and correction coil systems was serially connected both electrically and cryogenically. One of the major design goals, that of the magnets being protected by the ability to absorb their own energy, proved to be attainable. This is accomplished without external intervention, i.e. external extraction or driving the magnets normal by an active external circuit. This simply means the magnets L/R time constants during a quench are short enough to prevent thermal damage or run away. There are two series of prototypes. The first one is the so-called "standard" which will become the ring magnets for "ISABELLE" when the machine design is frozen. The second is that in which various characteristics and/or limits of various parameters are explored. Various parameters such as maximum ramp rate and other \dot{B} dependent phenomena are bracketed even though the present standard parameters are workable. There has also been obtained in the last two years operational data on four large (25 cm cold aperture, 2.5 m long) pool boiling dipoles. They have been an integral part of the High Energy Unseparated Beam guiding particles to the MPS (multiparticle spectrometer) of the AGS (30 GeV alternating gradient synchrotron, ISABELLE's injector).

We present results of our study of the neutron dissociation reaction n + p ..-->.. (p..pi../sup -/) + p for incident neutron momenta between 50 and 300 GeV/c. The integrated dissociation cross section for small values of (p..pi../sup -/) mass is essentially constant over this momentum interval. A strong correlation exists between the square of the four-momentum transfer (t) and the (p..pi../sup -/) rest mass, as well as between t and the decay angles of the (p..pi../sup -/) system. The observed (p..pi../sup -/) mass distribution is comprised of contributions from both narrow resonance like peaks and a broad low-mass continuum. Moments of the (p..pi../sup -/) decay angular distributions reveal rich structure, suggesting the presence of many partial waves.

We present results of our study of the neutron dissociation reaction $n+p\ensuremath{\rightarrow}(p{\ensuremath{\pi}}^{\ensuremath{-}})+p$ for incident neutron momenta between 50 and 300 GeV/c. The integrated dissociation cross section for small values of ($p{\ensuremath{\pi}}^{\ensuremath{-}}$) mass is essentially constant over this momentum interval. A strong correlation exists between the square of the four-momentum transfer ($t$) and the ($p{\ensuremath{\pi}}^{\ensuremath{-}}$) rest mass, as well as between $t$ and the decay angles of the ($p{\ensuremath{\pi}}^{\ensuremath{-}}$) system. The observed ($p{\ensuremath{\pi}}^{\ensuremath{-}}$) mass distribution is comprised of contributions from both narrow resonance like peaks and a broad low-mass continuum. Moments of the ($p{\ensuremath{\pi}}^{\ensuremath{-}}$) decay angular distributions reveal rich structure, suggesting the presence of many partial waves.

We present the results of a search at Fermilab for the charmed meson, ${D}^{\ensuremath{\circ}}(1865)$, produced in association with a prompt muon by 300-GeV/c neutrons. We observe no significant enhancement in high-mass ${K}^{\ifmmode\pm\else\textpm\fi{}}{\ensuremath{\pi}}^{\ensuremath{\mp}}$ systems and report, at the 95% confidence level, an upper limit of 200 nb/nucleon for the production of a pair of charmed particles and their subsequent decay into a ${K}^{\ifmmode\pm\else\textpm\fi{}}{\ensuremath{\pi}}^{\ensuremath{\mp}}$ state and a prompt muon.

In a single-arm spectrometer experiment, high-precision measurements of $\frac{d\ensuremath{\sigma}}{\mathrm{dt}}$ for ${\ensuremath{\pi}}^{\ensuremath{-}}p$, ${K}^{\ensuremath{-}}p$, and $\overline{p}p$ elastic scattering have been made at 8 and 16 GeV/c. The ${\ensuremath{\pi}}^{\ensuremath{-}}p$ data show rich structure at 8 GeV/c, indicative of strong non-Pomeron contributions, while the 16-GeV/c data are much smoother. For $\ensuremath{-}t\ensuremath{\gtrsim}1$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^{2}$ there is a strong $s$ dependence while there is very little for $\ensuremath{-}t<1$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^{2}$. For $\overline{p}p$ scattering the forward region is smoothly diffractive for $\ensuremath{-}t<0.4$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^{2}$ and shows antishrinkage. The exponential slope parameter $b$ is measured to be 12.36 \ifmmode\pm\else\textpm\fi{} 0.04 ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^{\ensuremath{-}2}$ at 8 GeV/c and 11.40 \ifmmode\pm\else\textpm\fi{} 0.04 ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^{\ensuremath{-}2}$ at 16 GeV/c. The structure near $\ensuremath{-}t=0.6$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^{2}$ seen at lower energies is still obvious at 16 GeV/c. The ${K}^{\ensuremath{-}}p$ data show some structure at 8 GeV/c, but can be represented adequately by a quadratic exponential form. At 16 GeV/c the ${K}^{\ensuremath{-}}p$ angular distribution shows antishrinkage and lies above the 8-GeV/c cross section for $0.11<\ensuremath{-}t<0.8$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^{2}$.