Browsing by Author "Phillips, Gerald C."
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Item 1.7-mev anomaly in Be_(1961) Bronson, Jeff Donaldson; Phillips, Gerald C.Item 3-body breakup of HE_(1963) Simpson, Wilburn Dwain; Phillips, Gerald C.The d(p,2p)n reaction has been studied using the recently constructed angular correlation chamber at Rice University. The two protons from the reaction have been observed for incident proton energies of 5.0, 9.0, and 10.5 MeV using the two Rice University Van de Graaff accelerators. Kinematic calculations were made to determine the shape of the curve describing allowed solutions in terms of the energy of one of the detected protons versus that of the other. Observed experimental curves of the same form have been presented along with the calculated excitation energies of the 3 possible intermediate configurations if the reaction were to proceed via sequential 2-body decay, Evidence of sequential 2-body decay to a low excited state of the n-p system is observed at particular angles for 9.0 and 10.5 MeV bombarding energies. Similar decay is not observed at 5.0 MeV, but this effect is likely due to experimental difficulties in observing the appropriate region of the energy curves at this energy. The data at all three bombarding energies and for many angles show evenly populated distributions, indicating for these cases either simultaneous 3-body decay of the He3 configuration or sequential 2-body decay through quite broad intermediate states.Item A binary encoded strip scintillation hodoscope for charged particle detection(1977) Hoftiezer, John H.; Phillips, Gerald C.A position-sensitive scintillation hodoscope with reduced photomultiplier use has been built. The device is an attempt to develop an economical, fast counter with good timing characteristics, good spatial resolution, and high efficiency. Isolated strips of plastic organic scintillator form a single layer (per dimension) detecting surface, while adiabatic light guides are encoded into a binary readout pattern such that photomultiplier use is reduced. The coding scheme, termed "error-free", identifies readout events as valid, or invalid, as in the cases of inefficiencies and multiple tracks. These counters were tested and successfully used to measure the incoming pion trajectories in a pion small angle scattering experiment. Further applications of the counters in high energy or highly ionizing particle experiments are expected.Item A differential pumping system for use with gas targets(1954) Reich, Charles William; Phillips, Gerald C.Item A large volume scattering chamber(1954) Russell, John Lynn; Phillips, Gerald C.A great deal of research in nuclear physics today is devoted to the tabulation of information, that can he obtained about the excited states of the nuclei. One nuclear property that can he determined experimentally is the total angular momentum. This thesis is a description of equipment that has been constructed for the purpose of gaining information about the angular momentum of nuclei.Item A new scattering system for polarized gas targets(1968) Boykin, Wilber Ray; Phillips, Gerald C.A scattering system consisting of gas target cell and surrounding vacuum chamber has been completed for studying scattering from polarized gas targets. This arrangement permits the use of thinner foil windows than would be possible if the target cell were exposed to atmospheric pressure. Optical pumping is employed to polarize the target. Scattered particles can be detected at laboratory angles of 30° to 150° on each side of the beam by two independently mounted surface barrier detectors whose positions can be controlled from outside the vacuum chamber while it is under vacuum. A description of the apparatus and technical construction data are given. Also included is a brief summary of the recent nuclear scattering experiments which utilized polarized beams and targets.Item A study of a multi-wire proportional counter for magnetic spectrograph focal plane detection(1972) Plasek, Ronald Eugene; Phillips, Gerald C.A multi-wire proportional counter (MWPC) was designed and successfully tested along the focal plane of the Rice University 65 cm magnetic spectrograph. The MWPC, which utilized .002" diameter stainless steel wires, a .100" wire spacing, and a .250" gap length, had an active area of 1" x 12". Counter efficiency and spatial resolution were determined by comparing the MWPC to results obtained with a position-sensitive solid state detector. The MWPC was thus found to be at least 98% efficient in the detection of 6 MeV protons. The spatial resolution of about 3 mm was limited by the multiple scattering of the protons in the counter foils and gas.Item A study of parallel plate proportional counters(1969) Scott, Marion Leon; Phillips, Gerald C.Current interest in a counter with fast response and thin transmission has led to the construction and study of a parallel plate proportional counter (PPPC). The PPPC was found to be essentially 100% efficient in the detection of 3 MeV protons. Gas gains near 104 were obtained in the pressure range between 177-355 torr. The rise time of the PPPC pulse for a plate separation of 5 mm was 35 nsec. The pulse height distribution indicates that zero-crossing timing should be used with the PPPC. A count rate of 103 counts/sec was discriminated from a background of 105 counts/sec by requiring coincidence with a scintillator. No degradation of the pulse height distribution was observed at this count rate.Item A target chamber for small angle scattering experiments(1976) Williams, Thomas Marion; Phillips, Gerald C.This target chamber was used in Experiment 8 at the Los Alamos Meson Physics Facility. Experiment 8 was designed to measure the total cross sections and the small angle cross sections for charged pions on C-12, Ca-4, and Pb-28. Particles can be detected from to 35 degrees on one side and from 1 to 18 degrees on the other side of the beam except near 75 degrees which is parallel to the plane of the target. A scintillator can be inserted on the small angle side to detect particles that miss the target. Any one of four target positions can be selected at the remote control, either of three targets or the target out position. This chamber can accept a beam of dimensions up to 3 by 5 inches. It was helium filled to reduce multiple scattering and to protect the calcium target. By measuring the total cross section and the small angle differential cross section, both the real and the imaginary parts of the forward scattering amplitude, f(°), can be determined.Item A time-of-flight spectrometer for fast neutron physics(1965) Keyes, Richard; Phillips, Gerald C.A time-of-flight spectrometer is described that was developed to further the study of the interactions of fast neutrons with nuclei at the Bonner Nuclear Laboratory of the Rice University. A transistorized time-to-pulse height converter utillizing avalanche-mode threshold discrimination and pulse shaping circuits is described. The results of resolution and linearity tests obtained with Na22 and Co60 y - sources are shown. Data from neutron-proton scattering experiments are presented to indicate the efficiency of the time-of-flight system.Item Absolute magnetic analysis of the alpha particles from polonium(1953) Gossett, Charles Robert; Phillips, Gerald C.The present state of the theoretical treatment of the field of nuclear phenomena, and in particular the basic subject of nuclear forces, is rather unsatisfactory. It appears quite probable that this subject will undergo a development parallel to that of atomic structures a considerable amount of information must be gathered before the theories which arise from time to time may be properly evaluated. As in the atomic oases one of the phenomena which a satisfactory theory must quantitatively explain is the existence of excited energy states in the nucleus, the presence of which are deduced from observation of quanta and particles emitted from such nuclei. In addition a satisfactory theory must certainly take into account the binding energies and, nuclear masses inferred from the energy release an the disintegration of nuclei. Of the many techniques currently employed to obtain the basic data mentioned above, one which yields great precision is that of charged particle energy measurement by magnetic analysis. In the past few years this method has been used to determine the disintegration energies, or "Q-values", and the energy levels of the light nuclei. It was for this purpose that the Rice Institute annular magnet was constructed: in 1949. This magnet has the advantage of being capable of absolute measurement, whereas the magnets employed by the groups at the Massachusetts Institute of Technology and the California Institute of Technology are calibrated by means of the alpha particle group from the natural radioactive element P0210. The Rice Institute magnet has to date been used only to check some of the determinations made by these two laboratories, which have been responsible for most such determinations made in this country. The rice data have been in reasonable agreement with the results of these laboratories, and this fact indicates that the calibration standards are, at most, not very much in error. However, it was felt that it would be advantageous to use the facilities for absolute measurement available at Rice to check this standard. It is for that purpose that the experiments described in this thesis were conducted.Item An application of correlation detection to the time of flight spectroscopy of particle fluxes(1975) Dragoset, William Henry; Phillips, Gerald C.Linear signal theory analysis has been applied to the problem of finding the time of flight spectra of random and pseudo-random particle fluxes. The results indicate that by employing the methods of correlation detection with suitable particle detectors, significant improvement in the time resolution in some cases and elimination of the pile-up problems of standard particle-by-particle TOF spectroscopy techniques can be achieved. Two different systems based on using correlation detection have been proposed for use with the time coherent LAMPF accelerator beams. One of these, a high speed camera, has been tested at LAMPF. The results of this test are presented. The second system, a method utilizing RF technology, has not been tested.Item An ionization chamber technique for the measurement of the transverse spin dependence of the proton-proton total cross-section(1981) Madigan, William Paul; Phillips, Gerald C.; Mutchler, Gordon S.; Baker, Stephen D.High precision ionization chambers were designed end built to measure the transverse spin dependence of the proton-proton total cross-section difference in the 318 MeV to 8 MeV energy region. Severe microphonic noise was minimized by mounting one of the chambers on pneumatic vibration isolators. Consideration of large fluctuations of the ionization produced in the thin gas layers of the chambers and the measured electronics noise accounts for about 6% of the resolution width of the measurement. Additional effects such as the beam intermittently scraping the target cavity, secondary emission of electrons, and beam-related RF pickup are postulated to account for the remaining width. Designing, constructing, and operation the high-precision ionization chambers has greatly improved our understanding of high-accuracy applications of ionization chambers and analog electronics.Item Angular distributions of protons and deuterons in the reactions A__(d,p)A__ and A__(d,d)A__(1959) Harris, Robert Wooten; Phillips, Gerald C.Item __B(p,2_)_He reaction at 163 keV(1966) Chen, Yu-Sau; Phillips, Gerald C.The 11B (p,2a)4 He reaction at a bombarding energy of 163 kev has been studied at Rice to complement the measurement previously made there at energies of a few Mev. Many 2-parameter spectra have been taken, both around the 8 Be* recoil axes and at selected angles away from the recoil axes. Coplanar and non-coplanar cases for the three a-particles have been studied. Preliminary analysis yields results similar to those found previously for the higher bombarding energies. Strong sequential decay through the 8 Be* states is observed with very little or no evidence for direct 3~a decay.Item [Delta]+ production in the PP --> PP[pi] [omicron] reaction at 800 MeV(1980) Pepin, Gregory Paul; Mutchler, Gordon S.; Phillips, Gerald C.; Baker, Stephen D.Fifth order differential cross sections have been measured for the reaction during two experiments using the 8 MeV External Proton Beam at the Los Alamos Meson Physics Facility (LAMPF). The kinematically complete data were obtained at seven angular settings covering a range of four-momentum transfers. The protons were detected by MWPC counters on two arms which measured the reaction angles for both charged particles. A magnetic spectrometer measured the momentum of one of the protons. The measured cross sections were compared to calculations using a peripheral model of pion production. Results indicate that the data can be fit with a single value of the pion form factor parameter whose value is much larger than that predicted using optical model calculations.Item Determination and stabilization of magnetic field strengths by means of proton magnetic resonance(1950) Jones, Richard Daniel; Phillips, Gerald C.Item Determination of the neutron threshold energy in the reactions C__(p,n)N__ and Li_(p,n)Be_(1959) Beckner, Everet Hess; Phillips, Gerald C.Item Excited states in Be_(1959) Sherrill, William Manning; Phillips, Gerald C.Item Gamma radiation from (d,p) and (d,n) reactions in nickel isotopes(1962) Rollefson, Aimar Andre; Phillips, Gerald C.