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This is a study of the use of a dual-beam, dual-detector synchrotron radiation system for transvenous coronary angiography in a human subject. This system eliminates the need for rapid beam switching, increases X-ray fluence by a factor of about 2.5, and makes it possible to record high- and low-energy images simultaneously, thus excluding artifacts arising from time subtraction. Besides coronary angiography, it may be possible to image the vertebral-basilar arterial circulation with this system.

The e + e − -storage ring DORIS II provides polarized beams with polarizations up to 80% in the energy range of the ϒ ′ meson. The method of resonance depolarization allows the average beam energy to be determined to a precision of ±0.1 MeV. An energy scan of the hadronic cross section over the resonance range with the detectors ARGUS and Crystal Ball determines the ϒ ′ mass to be (10023.1 ± 0.4) MeV.

This study is related to an evaluation of synchrotron radiation for the non-invasive assessment of coronary artery disease in humans. In vivo canine studies are reported for an imaging system developed for use with synchrotron X-ray beams. The probable configuration of an expanded system for pilot human subject studies is described.

Imaging of coronary arteries using a venous instead of an arterial injection of contrast agent could provide a much safer method to diagnose heart disease. The tunability, intensity, and collimation of synchrotron radiation x‐ray beams makes possible imaging systems with greatly improved imaging sensitivity. A pair of fan x‐ray beams, a movable patient chair, and a multielement x‐ray detector are used to acquire a pair of x‐ray images above and below the iodine K edge. The logarithmic subtraction of these two images produces an image with excellent sensitivity to contrast agent and minimal sensitivity to bone and tissue. High‐quality images from a dog and preliminary images from five humans have been obtained. Improvements are being made to the system to increase the effective radiation flux and to measure the position of both x‐ray beams.

Gamma-ray astronomy which includes the spectral region from above approximately 100 keV to greater than or equal to 1000 GeV permits investigation of the most energetic photons originating in our galaxy and beyond and provides the most direct means of studying the largest transfers of energy occurring in astrophysical processes. Of all the electromagnetic spectrum, high-energy gamma-ray astronomy measures most directly the presence and dynamic effects of the energetic charged cosmic ray particles, element synthesis, and particle acceleration. Further, gamma rays suffer negligible absorption or scatterings as they travel in straight paths; hence, they may survive billions of years and still reveal their source. The high energy processes in stellar objects (including our Sun), the dynamics of the cosmic-ray gas, the formation of clouds and nebulae, galactic evolution and even certain aspects of cosmology and the origin of the universe may be explored by gamma-ray observations.

Currently the imaging of coronary arteries is dangerous since it requires that a catheter be inserted into a peripheral artery and threaded up to the heart so that contrast agent can be injected directly into the artery being imaged. Using synchrotron radiation it may be possible to use a much safer venous injection of a contrast agent and still have sufficient image contrast to visualize the coronary arteries. A pair of monochromatized X-ray beams are used which have energies that bracket the iodine K absorption edge where the iodine absorption cross section jumps by a factor of six. Therefore, the logarithmic difference image has excellent sensitivity to contrast agent and minimal sensitivity to tissue and bone. Images have been taken of both dogs and humans. Improvements are being made to the imaging system which will substantially improve the image quality.

A search with the Crystal Box detector shows no evidence for the lepton-family-number-nonconserving decays ..mu -->..e..gamma.., ..mu -->..e..gamma gamma.., or ..mu -->..eee. The search provides upper limits for the branching ratios of GAMMA(..mu -->..e..gamma..)/GAMMA(..mu -->..evv-italic-bar) ..e..gamma gamma..)/GAMMA(..mu -->..evv-italic-bar) ..eee)/GAMMA(..mu -->..evv-italic-bar)

The risks and costs of the present method of visualizing the coronary arteries have limited the use of coronary angiography in long-term serial studies needed to establish the natural history of coronary atherosclerosis and its response to interventions. A less invasive method, in which the contrast agent is administered intravenously, has been developed using synchrotron radiation as the illuminating source. The present report describes the initial results in human subjects. The findings indicate that transvenous coronary angiograms can be acquired in this manner. Further refinements in the x-ray imaging system are expected to result in increased x-ray fluence and improved image quality.

Using the Crystal Ball detector at thee +e− storage ring DORIS-II, we have searched for the hadronic transitions Υ(2S)→ηΥ(1S) and Υ(2S)→π0Υ(1S) in exclusive decays where the Υ(1S) decays into ane +e− or aµ + µ - pair and the η and π0 are detected by their decay modes η→γγ, η→γγ and π0→γγ. From the number of observed events we derive, after consideration of possible background sources, upper limits on the branching ratiosB(Υ(2S)→ηΥ(1S))

X-ray-based angiography continues to be the standard method of assessing the severity and the extent of coronary atherosclerosis. The relative insensitivity of conventional X-ray imaging systems to iodine-containing contrast agents necessitates that the images be acquired with essentially undiluted contrast agent in the lumen of the vessels being studied. This, in turn, requires arterial catheterization and the insertion of the catheter tip in or near the ostia of the vessels and the direct injection of the contrast agent. The health risks and monetary costs of the procedure have limited its use to circumstances in which there is a high probability of the presence of severe disease. Despite these problems, coronary angiography has been employed in serial studies to evaluate the effects of drug therapy and diet on coronary atherosclerosis (1).

The intensity and tunability of synchrotron X-ray beams are highly suited to the non-invasive detection of iodine by K-edge digital subtraction angiography. An imnaging system developed for in vivo canine studies is described. Considerations relating to an expanded system for human subject studies are discussed.

A study at various temperatures has been made of approximately a dozen TlBr single crystals in order to find their properties as radiation induced conduction counters. Use of alpha particle sources showed whether holes or electrons were responsible for the observed behavior. Gamma ray studies showed rudimentary spectrometric performance whereas alpha particles usually resulted in peaks of approximately 25% fwhm. Long rise times were observed in some crystals and shorter rise times in others, the variability accounting for as much as a factor of 6. The energy required to produce a free electron-hole pair was observed to be 10.3 ± 2 eV. Breakdown phenomena were observed near room temperature and are described in the text.

During a series of experiments on crystal conduction counters performed at Stanford University on thallium halide crystals, we have observed motion of both hole and electron carriers in a TlBr crystal. At a temperature near -90 /sup 0/C the hole motion produces larger pulses than electron motion. We have studied the behavior of TlBr, TlCl, and KRS-5 (40 mol % TlBr + 60 mol % TlI) crystals and examined them as possible crystal conduction detectors of ..cap alpha.. particles and ..gamma.. rays. TlBr appears to be a promising candidate for applications to nuclear physics and high-energy ..gamma..-ray physics. Modules of TlBr in ''crystal-ball'' geometry may lead to new detection possibilities. At -20 /sup 0/C space-charge accumulation in TlBr decreases to such an extent that operation at this temperature seems possible with moderate electrical gradients. In the long-neglected field of crystal conduction counters, we have potentially removed the space-charge limitation in TlBr and, allowing for both hole and electron motion, raised the possibility for spectroscopic performance of this material for ..gamma..-ray studies.

The data acquisition system for the Crystal Ball project at SLAC is described. A PDP-11/t55 using RSX-11M connected to the SLAC Triplex is the basis of the system. A "physics pipeline" allows physicists to write their own equipment-monitoring or physics tasks which require event sampling. As well, an interactive analysis package (MULTI) is in the pipeline. Histogram collection and display on the PDP are implemented using the Triplex histogramming package. Various interactive event displays are also implemented.

The application of coronary angiography is limited because it requires arterial invasion and the direct injection of contrast agent into the coronary arteries. A prototype system has been developed which achieves sufficient sensitivity to the iodinated contrast agent to allow the visualization of coronary arteries in dogs after its intravenous injection. The system uses two fan beams of x-rays from an electron storage ring and a 300 element linear silicon detector. Two interlaced images, spaced at 150 eV above and below the K absorption edge of iodine (33.2 keV), are acquired and the logarithmic subtraction of these two images produces an image which has maximal sensitivity to iodine and minimal sensitivity to soft tissue and bone. This approach appears suitable for studies on human subjects.

Synchrotron radiation provides a new source of X-rays highly-suited to iodine K-edge Digital Subtraction Angiography (DSA). The use of such beams provides maximum sensitivity to intra-arterial iodine and virtually eliminates image contrast due to non-vascular body structures. The intensity of the beams permits short exposure times and allows images to be recorded, in line-scan fashion, in sharp focus despite arterial motions. The sensitivity of this method offers the prospect of visualizing arteries, and in particular the coronary arteries, by peripheral venous injection. The principles of DSA have been demonstrated using phantoms and excised animal hearts, and in vivo studies in animals have begun. The instrumentation developed for this purpose and the results obtained to date are summarized.

Using the Crystal Ball detector operating at the DORIS II storage ring we have measured the leptonic partial widthsГ ee of the Υ(1S) and Υ(2S) resonances. We find $$\Gamma _{ee} (\Upsilon (1S)) = 1.34 \pm 0.03 \pm 0.06keV$$ and $$\Gamma _{ee} (\Upsilon (2S)) = 0.56 \pm 0.04 \pm 0.02keV.$$ The effect onГ ee of applying different prescriptions for radiative corrections is discussed. We also measureR, the ratio of non-resonant hadronic cross section to the Born cross section of μ pair production, at c.m. energyW=9.39 GeV to beR=3.48±0.04±0.16.

The intense synchrotron radiation produced by wiggler magnets at electron storage rings provides a new source of x-rays highly suited to iodine K-edge digital subtraction angiography. The monochromaticity and tunability provide maximum sensitivity to intraarterial iodine and virtually eliminate contrast due to soft tissue and bone. Visualization of arteries, in particular the coronary arteries, by peripheral venous injection is possible. A system design, based on tests already performed, is presented.

Because coronary disease represents the principal health problem in the Western, industrialized world, and because of the risks and costs associated with conventional methods of visualizing the coronary arteries, an effort has been underway at the Stanford Synchrotron Radiation Laboratory to develop a less invasive coronary imaging procedure based on iodine K-edge dichromography. A pair of line images, recorded within a few milliseconds of each other, is taken with two monochromatic X-ray beams whose energy closely brackets the K-edge of iodine, 33.17 keV. The logarithmic subtraction of the images produced by these beams results in an image which greatly enhances signals arising from attenuation by iodine and almost totally suppresses signals arising from attenuation by soft tissue and bone. The high sensitivity to iodine allows the visualization of arterial structures after an intravenous injection of contrast agent and its subsequent 20-30 fold dilution. The experiments began in 1979, with initial studies done on phantoms and excised pig hearts. The first images of anesthetized dogs were taken in 1982. The results of experiments on dogs will be reviewed, showing the stepwise evolution of the imaging system, leading to the use of the system on human subjects in 1986. The images recorded on human subjects will be described and the remaining problems discussed.

A program is underway at the Stanford Synchrotron Radiation Laboratory to evaluate at minimally invasive method of visualizing the coronary arteries in man using synchrotron radiation. The design of an X-ray imaging system to accomodate a newly-available X-ray beam 12.3 cm in width is described. The system performance as revealed with test images of phantoms and excised hearts is indicated, and the system components to be tested before clinical studies can begin are identified.

The properties of detector arrays made up of NaI(Tl) Polyscin modules 20 in. deep and of hexagonal cross section and the development of a Monte Carlo code of general use in the design of such detectors are described. The use of modularized NaI(Tl) detectors in the study of a new spectroscopy of ?-rays in high energy physics is outlined.

The Crystal Ball detector at the Doris II storage ring at DESY was used to search for the exotic decay processes τ →e γ , τ →e π 0 , and τ →e η . No signal was observed. We obtained the following 90% CL upper limits on the branching fractions: B ( τ →e γ ) −4 , B ( τ →e π 0 ) −4 , B ( τ →e η ) −4 .

Experimental results are presented on the scattering of 250-MeV electrons by ${\mathrm{Ca}}^{40}$, ${\mathrm{Ca}}^{42}$, ${\mathrm{Ca}}^{44}$, ${\mathrm{Ca}}^{48}$, and ${\mathrm{Ti}}^{48}$, and of 500-MeV electrons by ${\mathrm{Ca}}^{40}$ and ${\mathrm{Ca}}^{48}$. An analysis is made in terms of a phenomenological three-parameter shape, and a new, more accurate charge distribution is obtained for ${\mathrm{Ca}}^{40}$. The experiments also lead to a detailed exploration of the radial dependence of the differences in charge distributions of the various isotopes. Implications for nuclear theory are discussed. Comparison is made with the results of other electron scattering and of muonic x-ray experiments. The latter comparison permits an independent determination of an upper limit on the muon electromagnetic radius ${{〈{r}^{2}〉}_{\ensuremath{\mu}}}^{\frac{1}{2}}\ensuremath{\lesssim}0.35$ F.

The electric and magnetic form factors of the proton and neutron are derived theoretically as functions of the momentum transfer invariant (q/sup 2/). It is proposed that the proton and nucleon are two aspects of the nucleon, which differ only in isctopic spin. The neutron and proton form factors are accordingly divided into scalar and vector parts, and the effects of core charges and Yukawa clouds are discussed. It is noted that the neutron electric form factor is positive, thus requiring a pcsitive outer fringe of charge for the neutron. (T.F.H.)

The elastic scattering peak in carbon-12 is accompanied by a number of additional peaks corresponding to inelastic scattering of electrons from the various excited levels of the carbon nucleus. Three levels have been investigated by this method and correspond to the three known states at 4.43 Mev, 7.68 Mev, and 9.61 Mev. Angular distributions of the inelastically-scattered electrons have been obtained as well as the angular distribution of the elastically-scattered electrons. The angular distributions of the inelastic peaks fall off less steeply with angle than the elastic peak. By comparing the scattering from carbon with scattering from the proton, and using the theoretical value of the cross section of electrons scattered from the proton, it is possible to obtain "absolute" values for the elastic and inelastic scattering cross sections. From the elastic-scattering curve, information about the size and charge distribution in the carbon-12 nucleus may be derived. The charge distribution lies halfway between a Gaussian and a uniform model. The root mean square radius of the resultant charge distribution is (2.40\ifmmode\pm\else\textpm\fi{}0.25)\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}13}$ cm.

Thallium-activated sodium iodide crystals may be used as efficient detectors of gamma-rays and other ionizing radiations. The crystals are used in combination with a photo-multiplier after the manner of Kallmann. Curves are given which show the duration of the light emission process, the distribution of light pulse sizes, the energy discrimination possibilities, and the dependence of number of counting events on photo-multiplier voltage and amplifier gain. Comparison curves are shown for NaI(Tl) and anthracene. A description is given of the method of preparation of polycrystalline samples and single crystal specimens of the sodium iodidethallium phosphor. A few remarks are made concerning the combination of alkali halide phosphor crystals with photographic plates.

The elastic scattering of 188-Mev electrons from gaseous targets of hydrogen and helium has been studied. Elastic profiles have been obtained at laboratory angles between 35\ifmmode^\circ\else\textdegree\fi{} and 138\ifmmode^\circ\else\textdegree\fi{}. The areas under such curves, within energy limits of \ifmmode\pm\else\textpm\fi{}1.5 Mev of the peak, have been measured and the results plotted against angle. In the case of hydrogen, a comparison has been made with the theoretical predictions of the Mott formula for elastic scattering and also with a modified Mott formula (due to Rosenbluth) taking into account both the anomalous magnetic moment of the proton and a finite size effect. The comparison shows that a finite size of the proton will account for the results and the present experiment fixes this size. The root-mean-square radii of charge and magnetic moment are each (0.74\ifmmode\pm\else\textpm\fi{}0.24)\ifmmode\times\else\texttimes\fi{}${10}^{13}$ cm. In obtaining these results it is assumed that the usual laws of electromagnetic interaction and the Coulomb law are valid at distances less than ${10}^{\ensuremath{-}13}$ cm and that the charge and moment radii are equal. In helium, large effects of the finite size of the alpha-particle are observed and the rms radius of the alpha particle is found to be (1.6\ifmmode\pm\else\textpm\fi{}0.1)\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}13}$ cm.

The mirror nuclei of tritium and helium-3 have been studied by the method of elastic electron scattering. Absolute cross sections have been measured for incident electron energies in the range 110-680 MeV at scattering angles lying between 40 and 135\ifmmode^\circ\else\textdegree\fi{} in this energy range. The data have been interpreted in a straightforward manner and form factors are given for the distributions of charge and magnetic moment in the two nuclei over a range of four-momentum transfer squared 1.0-8.0 ${\mathrm{F}}^{\ensuremath{-}2}$. Model-independent radii of the charge and magnetic-moment distributions are given and an attempt is made to deduce form factors describing the spatial distribution of the protons in tritium and helium-3.

Using high-resolution semiconductor detectors, a study was made of the large $K$-ionization cross sections of atoms over a wide range of atomic numbers ($Z=29\ensuremath{-}83$) and of incident electron energies ($E=150\ensuremath{-}900$ MeV). For the higher-$Z$ elements ($Zg60$), the $L$ x-ray cross sections were also measured over the incident electron energy range. Ratios of the relative intensities of various distinct lines were determined and compared to recent low-energy work. The results of the $K$-ionization experiment are compared to the recent relativistic calculations of Kolbenstvedt. The experimental $K$-ionization cross sections for each incident electron energy appear to fit a power-law dependence on the atomic number. The Kolbenstvedt theory also exhibits a power-law dependence and is in good agreement with this experiment. All differential x-ray cross sections were found to be isotropic. The $L$ x-ray cross sections measured for four high-$Z$ elements increase with atomic number and incident electron energy. The $\frac{L\ensuremath{\beta}}{L\ensuremath{\alpha}}$, $\frac{L\ensuremath{\gamma}}{L\ensuremath{\alpha}}$, and $\frac{K}{L}$ intensity ratios are also given. A search for nuclear $\ensuremath{\gamma}$ rays produced by high-energy electron scattering was also undertaken in this work. No nuclear $\ensuremath{\gamma}$-ray lines were detected. Recent theoretical calculations show that the expected cross sections are below the minimum observable levels in these experiments. However, a 511-keV $\ensuremath{\gamma}$ line was observed. This line was associated with positron annihilation and was apparently produced in the target.

The study of electrons scattered inelastically from the deuteron has been extended to 600 Mev. Data at 500 Mev were reported in an earlier paper. Results are presented for seven scattering angles between 45\ifmmode^\circ\else\textdegree\fi{} and 135\ifmmode^\circ\else\textdegree\fi{}. A comparison of the deuteron's cross section at these angles with the corresponding free proton cross sections permits a determination of the form factor associated with the magnetic moment distribution of the neutron. Two different methods of analyzing the data are described, and the rms radius of the neutron for an exponential density distribution of the magnetic cloud can be shown to lie between the limits of 0.75\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}13}$ cm and 0.95\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}13}$ cm. The rms radius of the neutron may be taken to be (0.80\ifmmode\pm\else\textpm\fi{}0.10)\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}13}$ cm and is very close to the value found for an exponential model of the magnetic cloud in the proton.

New information is reported on differences between the charge distributions of Ca40 and of Ca44, obtained by means of elastic scattering of 250 MeV electrons. Attention is focused, experimentally and theoretically, on the difference in scattering between the two isotopes.

The scattering of high-energy electrons from ${\mathrm{C}}^{12}$, reported previously, has been extended to 420 Mev. The elastic and inelastic scattering from the first excited level at 4.43 Mev has been studied between 33\ifmmode^\circ\else\textdegree\fi{} and 70\ifmmode^\circ\else\textdegree\fi{}. The new data are in good agreement with what one would expect from the earlier measurements on ${\mathrm{C}}^{12}$ performed at 187 Mev. Additional measurements of the elastic ${\mathrm{O}}^{16}$-scattering cross sections of 240-, 360-, and 420-Mev electrons as functions of the scattering angle furnish information on the size and shape of the ${\mathrm{O}}^{16}$ nucleus. Pronounced diffraction minima in the angular distributions were observed for ${\mathrm{C}}^{12}$ and ${\mathrm{O}}^{16}$. The experimental results are compared with the predictions of a theoretical phase-shift analysis derived for the harmonic-well independent-particle model of the nucleus. Preliminary best fits confirm the shell-model predictions for the charge density distribution of these $p$-shell nuclei. The preliminary analysis of the data shows that the length parameter of the well is 1.66\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}13}$ cm for ${\mathrm{C}}^{12}$, and 1.76\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}13}$ cm for ${\mathrm{O}}^{16}$, thus indicating a slight variation of the curvature of the harmonic well as the $p$ shell is filled in.

Measurements are reported of the inelastic scattering of electrons from the mirror nuclei of tritium and helium - 3. The ratio of the quasi-elastic electron-tritium and electron-helium -3 cross sections was measured to a precision of about 3% for values of the square of the four-momentum transfer, equal to 2.5 and 4.6/F sq. Detailed measurements of the shape of the entire inelastic spectra and estimates of the total inelastic cross sections were made. While these data are primarily intended to furnish additional experimental information which will be of use in determining the structure of the three-body nuclei, it is also pointed out that such data are a possible source of information on the structure of the neutron. (Author)