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EXPERIMENTAL PROBLEMS IN THE USE OF A POLARIZED PROTONTARGET

Description: I have understood my assignment as a review of some of the work done in high-energy physics with polarized proton targets and a description of some of the special problems connected with polarized targets. Most of my report will be based on the polarized target that I am most familiar with--that constructed by Jeffries, Schultz, Shapiro, and myself. This target is no longer unique; in fact, it is now somewhat old-fashioned in some respects. Other polarized proton targets are in operation at CERN, Saclay, the Rutherford Laboratory, Argonne National Laboratory, the Soviet Union, and there is a target newly in operation at the Brookhaven Laboratory. Other targets are in operation or are in the process of design or construction at a number of other places. Unfortunately, none of these targets consists of pure hydrogen. The target material most often used is made of lanthanum magnesium nitrate, LMN. About a quarter of the weight of this crystal is water; it is the protons within the water molecules that are polarized. Hydrogen constitutes only 3 percent of the weight of the crystal. This means that scattering processes on hydrogen must be distinguished kinematically from scattering processes involving the heavy elements of the target if the target is to be used efficiently in high-energy scattering experiments. In fact, some of the experiments one would very much like to do appear to be very difficult. In LMN the protons are polarized by an indirect process known as dynamic polarization. Neodymium ions are added to the crystal when it is grown from a water solution. The neodymium ions are substituted for lanthanum to the extent of one percent or less. The neodymium ion has an odd number of electrons; it has a doublet ground state, called a Kramers doublet, that acts very much like a ...
Date: September 9, 1966
Creator: Chamberlain, Owen
Partner: UNT Libraries Government Documents Department

STUDIES ON THE CHEMICAL AND PHOTOCHEMICAL OXIDATION OFBACTERIOCHLOROPHYLL

Description: A simplified procedure is described for the preparation of crystalline bacteriochlorophyll from R. rubrum. The chemical dehydrogenation of bacteriochlorophyll with quinones is shown to give high yields of 2-desvinyl-2acetyl-chlorophyll a, whereas the photo-oxidation of bacteriochlorophyll results in a mixture of products of which 2-desvinyl-2acetyl-chlorophyll a is only a minor constituent. A number of interesting results have been observed spectrophotometrically during these oxidations under different reaction conditions. These observations are discussed and possible reaction mechanisms are outlined. The proton magnetic resonance spectrum of 2-desvinyl-2acetyl-chlorophyll a in deuteroacetone and the visible absorption spectra of this pigment and its magnesium-free derivative in acetone are reported. As expected, these spectra exhibit a marked resemblance to chlorophyll a and pheophytin a.
Date: June 1, 1966
Creator: Smith, John R. Lindsay & Calvin, Melvin
Partner: UNT Libraries Government Documents Department

HIGH-ENERGY-PHYSICS EXPERIMENTS WITH POLARIZED TARGETS

Description: If we are to do a workmanlike job of studying the strong interactions it is imperative that we have knowledge of the spin dependence of the forces. This implies that polarization experiments are essential. Already Bareyre, Bricman, Stirling and Villet have shown that pion-proton polarization experiments should be interpreted as indicating two new resonances not previously seen by other methods. The present-day approach to determining detailed pion-proton scattering amplitudes is to use measured differential cross sections, polarization measurements, dispersion relations, and isospin conservation rules. Further assumptions are unitarity of the S matrix and the short-range nature of strong interactions. In the more distant future I hope we may see the day when the scattering experiments will be sufficiently detailed that the dispersion relations will not be necessary to the interpretation of results. Then the dispersion relations may themselves be checked experimentally, rather than being assumed. I see, then, an early period of polarization experiments followed by a later period in which more extensive experimental results will be called for. For the pion-proton system the first period seems well progressed, based on measurements of differential cross section and P, the polarization. In the second period more complex experiments should be required, such as measurements of the parameters R and A . In R and A measurements, the protons have a known polarization before the collision takes place. After the pion scatters on the proton, one asks how much residual polarization the proton has. The nucleon-nucleon (N-N) system is susceptible to similar analysis, but there are more amplitudes to be determined, so more experiments must be performed. The N-N system is less well analyzed at present than the {pi}-N system.
Date: December 1, 1966
Creator: Chamberlain, Owen
Partner: UNT Libraries Government Documents Department

SELECTIVITY IN ZEOLITE OCCLUSION OF OLEFINS

Description: Selective occlusions of straight-chain paraffins in the presence of branched-chain hydrocarbons by naturally occurring zeolites of suitable dimension was reported as early as 1944 by Barrer and Ibbitson. More recently the capacity of synthetic zeolites or molecular sieves to absorb exclusively the straight-chain hydrocarbons from complex hydrocarbon mixtures has found extensive application in the petroleum industry. Under the conditions developed for most sieving operations any normal olefins present are occluded along with the normal paraffins. A supplemental separation technique must be employed to obtain n-paraffins free of olefins.
Date: August 30, 1966
Creator: Fenselau, Catherine & Calvin, Melvin
Partner: UNT Libraries Government Documents Department

CHEMICAL TRAPPING OF A PRIMARY QUANTUM CONVERSION PRODUCT INPHOTOSYNTHESIS

Description: The capacity of photosynthetic organisms to exhibit photo-induced electron paramagnetic resonance (EPR) signals has been known for over ten years. Subcellular units of photosynthetic materials, the quantasomes and the chromatophores, are capable of Hill Reaction activity, and also of exhibiting the light-induced EPR signals. This, coupled with the rapid rise and decay kinetics of these signals, suggests but does not prove that the unpaired electrons are involved in the initial electron transfer processes in the primary quantum conversion act. The identification of the species giving rise to these signals and their connection with processes of primary quantum conversion remains elusive even though such varied approaches as mutant strains, special growth conditions, extreme physical conditions, special metabolic inhibitors, etc. have been applied to this problem. In this communication the authors wish to report another method being used in an attempt to identify the species responsible for the unpaired electrons. Hoffman prepared a water soluble, stable free radical, di-tertiary-butylnitroxide (hereafter called DTBN), which is a 'vigorous free radical scavenger'. It shows a sharp, well resolved, symmetrical, three-line paramagnetic resonance spectrum that is relatively insensitive to the molecular environment. The chemistry of di-tertiary butylnitroxide has not been studied extensively. However, four distinct types of interaction can be envisioned for this molecule. It could undergo a one-electron reduction to form a hydroxylamine which can be reduced subsequently to the amine; an oxidative degradation to 2-methyl-2-nitrosopropane and isobutylene; or a coupling with another radical forming either an oxygen substituted hydroxylamine or a tri-substituted amine oxide.
Date: September 9, 1966
Creator: Corker, Gerald A.; Klein, Melvin P. & Calvin, Melvin.
Partner: UNT Libraries Government Documents Department

A HIGH-RESOLUTION HIGH-LUMINOSITY BETA-RAY SPECTROMETER DESIGN EMPLOYING AZIMUTHALLY VARYING MAGNETIC FIELDS

Description: A double-focusing magnetic field for a spectrometer of the flat type which gives radial focusing to roughly the sixth order, and which utilizes azimuthal variation of the field coefficients, has been devised.
Date: April 6, 1966
Creator: Bergkvist, Karl-Erik & Sessler, Andrew M.
Partner: UNT Libraries Government Documents Department

WAKE FIELDS OF A PULSE OF CHARGE MOVING IN A HIGHLY CONDUCTING PIPE OF CIRCULAR CROSS SECTION

Description: Expressions are presented for the electric and magnetic fields due to a pulse of charge, which may be oscillating transversely while moving down an infinitely long highly conducting pipe of circular cross section. The expressions are evaluated at large distances from the pulse and the fields are shown to decrease algebraically in the distance behind the pulse. In the absence of transverse oscillations the longitudinal electric field varies as the inverse three-halves power of the distance; in the presence of oscillations the dominant field component is the transverse magnetic field, which decreases as the inverse one-half power. In the long-range limit the amplitude of the fields is proportional to the square root of the wall resistivity. The phase of the field associated with the oscillating pulse is shown to be the phase of the pulse at the time when it passed the point of observation.
Date: February 28, 1966
Creator: Morton, P.L.; Neil, V.K. & Sessler, A.M.
Partner: UNT Libraries Government Documents Department

TRANSVERSE COHERENT RESISTIVE INSTABILITIES OF AZIMUTHALLY BUNCHED BEAMS IN PARTICLE ACCELERATORS

Description: The transverse electromagnetic coupling of bunches of particles with each other is investigated theoretically, and shown to incorporate the possibility (due to the effect of nonperfectly conducting vacuum chamber walls) of coherent instability even when the longitudinal distance between bunches is much larger than the transverse dimensions of the vacuum tank. The modes of oscillation in which the bunches move rigidly are investigated; criteria for stability, and expressions for the small amplitude growth rates under unstable conditions are presented. The case of a single bunch is considered in detail and demonstrated to be stable (even in the absence of landau damping) provided {nu} lies between an integer and the next higher half-integer, where {nu} is the number of transverse free betatron oscillations occurring in one revolution; for many bunches which are sensibly different in intensity (a criterion for this is presented), all modes are stable provided {nu} satisfies the same restriction. For equally spaced bunches of equal numbers of particles, approximately half the modes are unstable without Landau damping. Numerical examples are presented covering some intermediate situations.
Date: April 1, 1966
Creator: Courant, Ernest D. & Sessler, Andrew M.
Partner: UNT Libraries Government Documents Department

ROTATION OF MERCURY: THEORETICAL ANALYSIS OF THE DYNAMICS OF A RIGID ELLIPSOIDAL PLANET

Description: The second-order nonlinear differential equation for the rotation of Mercury is shown to imply locked-in motion when the period is within the range (2T/3) [1-{lambda} cos 2{pi}t/T {+-} 2/3 (21{lambda}e/2){sup 1/2}], where e is the eccentricity and T the period of Mercury's orbit, the time t is measured from perihelion, and {lambda} = (B-A)/C measures the planet's distortion. For values near 2T/3, the instantaneous period oscillates about 2T/3 with period (21{lambda}e/2){sup -1/2}T.
Date: January 1, 1966
Creator: Laslett, L. Jackson & Sessler, Andrew M.
Partner: UNT Libraries Government Documents Department

POLARIZATION IN PION-PROTON SCATTERING FROM 670-3750 MeV/c

Description: Using a polarized proton target, we have measured the polarization parameter P({theta}) in pion-proton scattering for both positive and negative pions. Because there seems to be a great deal of current interest in the analysis of pion-proton scattering we wish to present these experimental results at this time even though we have not yet completed their analysis. The measurement consisted of scattering pions from polarized target protons and observing the asymmetry in scattered intensity, I({theta}), as the target protons spin directions were reversed. The intensity for scattering from a target of polarization P{sub T} is I({theta}){sub pol.} = I({theta}){sub unpol.} (1 + P({theta})P{sub T}), where the parameter P({theta}) is the same as the recoil proton polarization in scattering pions from unpolarized protons under the assumption that parity is conserved in the process.
Date: October 1, 1966
Creator: Chamberlain, Owen; Hansroul, Michel J.; Johnson, Claiborne H.; Grannis, Paul D.; Holloway, Leland E.; Valentin, Luc et al.
Partner: UNT Libraries Government Documents Department

LAWRENCE RADIATION LABORATORY COUNTING HANDBOOK

Description: The Counting Handbook is a compilation of operational techniques and performance specifications on counting equipment in use at the Lawrence Radiation Laboratory, Berkeley. Counting notes have been written from the viewpoint of the user rather than that of the designer or maintenance man. The only maintenance instructions that have been included are those that can easily be performed by the experimenter to assure that the equipment is operating properly.
Date: October 1, 1966
Creator: Group, Nuclear Instrumentation
Partner: UNT Libraries Government Documents Department

DECAY PROPERTIES OF THE E HYPERON AND E RESONANCES

Description: A sample of 2500 {Xi}{sup -} and 500 {Xi}{sup 0} hyperons, produced in {Xi}K, {Xi}K{pi}, and {Xi}K{pi}{pi} final states by K{sup -} (in H{sub 2}) at incident momenta of 1.7 to 2.7 BeV/c, has been analyzed. The data are from an exposure (K-63) of 26 events/{mu}b in the 72-inch bubble chamber; approximately 85% of the {Xi}{sup -} events and 60% of the {Xi}{sup 0} events have been analyzed. For the {Xi}, they determine the spin and decay parameters a{sub {Xi}} and {Phi}{sub {Xi}} = tan{sup -1} ({beta}{sub {Xi}}/{Gamma}{sub {Xi}}). Combining their data with 900 {Xi}{sup -} and 150 {Xi}{sup 0} events from an earlier experiment (K-72), they obtain the following results: (1) {Xi} spin - J = 1/2 favored over J = 3/2 by {approx} 2.5 standard deviations; (2) {Xi} decay parameters (assuming a{sub {Lambda}} = 0.647 {+-} 0.048) - a{sub {Xi}{sup -}} = -0.398 {+-} 0.041, {Phi}{sub {Xi}{sup -}} = 9.8{sup o} {+-} 9.0{sup o}; a{sub {Xi}{sup 0}} = -0.413 {+-} 0.104. They observe {Xi}*(1530) and {Xi}*(1817); their data are insufficient for analysis of suggested {Xi}* resonances at 1705 and 1933 MeV. They measure the {Xi}*(1530) electromagnetic mass difference {Delta}m = m({Xi}*{sup -}) = m({Xi}*{sup 0}) = 2.0 {+-} 3.2 MeV. Using data, part of which has already been described, they find for {Xi}*(1530): J {ge} 3/2 favored over J = 1/2 (the J = 1/2 hypothesis is {approx} 3.5% as probable as the J = 3/2 hypothesis); J{sup P} = 3/2{sup +} favored over 3/2{sup -} by {approx} 2.8 standard deviations. For {Xi}*(1817) decaying into {Xi}*(1530) + {pi}, the hypotheses J{sup P} = 1/2{sup +}, 1/2{sup -}, 3/2{sup -}, 5/2{sup +}, 7/2{sup -}, etc. (corresponding to {ell} = 1, 2, 0 and 2, 1 and 3, and 2 and 4, respectively) are favored over other hypotheses, but results ...
Date: September 10, 1966
Creator: Merrill, Jr., Deane W.
Partner: UNT Libraries Government Documents Department

NUCLEAR SPECTROSCOPIC STUDIES OF SOME VERY HEAVY ODD-MASS NUCLIDES

Description: The nuclear radiations of nuclides: U{sup 233}, Pu{sup 239}, Bk{sup 243}, Bk{sup 244}, Bk{sup 245}, Bk{sup 246}, Bk{sup 249}, Cf{sup 249}, and Fm{sup 255} were investigated with high-resolution spectrometers. The {alpha}-particle spectra of all nuclides except Bk{sup 249} were measured with 6 mm diameter surface-barrier detectors. Bk{sup 249} {alpha}-particles were analyzed with a double-focusing magnetic spectrograph. The {gamma}-singles were examined with the recently developed Ge(Li) and Si(Li) detectors coupled with very-low noise 'internal FET' preamplifiers. Weak alpha groups were observed in coincidence with {gamma}-rays, detected with a NaI(Tl) scintillation spectrometer. To improve the over-all coincidence efficiency a new coincidence apparatus was designed and built. This instrument consisted of a cooled 4.5 cm diameter semiconductor detector for {alpha}-particle detection and a 3 cm diameter by 2.7 cm long Ge(Li) detector for {gamma}-ray analysis. The Ge(Li) detector could also be replaced with a NaI(Tl) detector. Cf{sup 249} conversion electrons were measured with a cooled Si(Li) detector coupled with an internal FET preamplifier. On the basis of the present work and previous information, energy-level diagrams of the daughter nuclei have been constructed. The levels have been grouped into rotational bands built on Nilsson single-particle states. Because of identification of several rotational members of the bands, definite Nilsson quantum number assignments have been made in most cases. The alpha intensity calculations of Poggenburg were found quite helpful in making these assignments. A strong Coriolis effect was observed in the Am{sup 245} levels populated by the alpha groups of Bk{sup 249}. Calculations were made with Nilsson wave-functions, and these were found to agree with the experimental results. The Coriolis interaction was found important in almost all cases; the effect was very noticeable in the level spacings between the rotational members of the bands. High-lying bands in Cm{sup 245} (at 644 keV) and cf{sup 251} (at ...
Date: September 20, 1966
Creator: Ahmad, Irshad
Partner: UNT Libraries Government Documents Department