Physics Commons^™

New Limit On Time-Reversal Violation In Beta Decay, H. P. Mumm, T. E. Chupp, R. L. Cooper, K. P. Coulter, S. J. Freedman, B. K. Fujikawa, A. Garcia, Gordon L. Jones, J. S. Nico, A. K. Thompson, C. A. Trull, J. F. Wilderson, F. E. Wietfeldt

Articles

We report the results of an improved determination of the triple correlation DP . (p(e) x p(v)) that can be used to limit possible time-reversal invariance in the beta decay of polarized neutrons and constrain extensions to the standard model. Our result is D = [-0.96 +/- 1.89(stat) +/- 1.01(sys)] x 10(-4). The corresponding phase between g(A) and g(V) is phi(AV) = 180.013 degrees +/- 0.028 degrees (68% confidence level). This result represents the most sensitive measurement of D in nuclear beta decay.

The Economics Of The Atomic Bomb: Cost And Utilization, Jonathan M. Davis Mr.

Senior Honors Theses

Few moments in human history can be compared to the culmination of events that brought the atomic bomb into creation. It is incredible to contemplate that while a nation was fighting a two front war that spanned from Europe into the Pacific, that the United States was able to utilize the time, energy, brains, materials, manpower, and capital to complete a project in four years. That under any other circumstances would have taken greater than half a century to complete.

First, this thesis will discuss breakthroughs in research that led scientists to believe that the atomic weapons could be built, …

Measurement Of Parity-Violating Gamma-Ray Asymmetry In The Capture Of Polarized Cold Neutrons On Protons, M. T. Gericke, R. Alacorn, S. Balascuta, L. Barron-Palos, C. Blessinger, J. D. Bowman, R. D. Carlini, W. Chen, T. E. Chupp, C. Crawford, S. Covrig, M. Dabaghyan, N. Fomin, S. J. Freedman, T. R. Gentile, R. C. Gillis, G. L. Greene, F. W. Hersman, T. Ino, Gordon L. Jones, B. Lauss, M. Leuschner, W. R. Lozowski, R. Mahurin, Y. Masuda, J. Mei, G. S. Mitchell, S. Muto, H. Nann, S. A. Page, S. I. Penttila, W. D. Ramsay, A. Salas-Bacci, S. Santra, M. Sharma, P.-N. Seo, E. I. Sharapov, T. B. Smith, W. M. Snow, W. S. Wilburn, V. Yuan

Articles

The NPDGamma collaboration reports results from the first phase of a measurement of the parity violating up-down asymmetry A(gamma) with respect to the neutron spin direction of gamma rays emitted in the reaction (n) over right arrow + p -> d + gamma using the capture of polarized cold neutrons on the protons in a liquid parahydrogen target. One expects parity-odd effects in the hadronic weak interaction between nucleons to be induced by the weak interaction between quarks. A(gamma) in (n) over right arrow + p -> d + gamma is dominated by a Delta I = 1, S-3(1)-P-3(1) parity-odd …

Two-Loop Soft Anomalous Dimensions For Single Top Quark Associated Production With A W- Or H-, Nikolaos Kidonakis

Faculty and Research Publications

I present results for the two-loop soft anomalous dimensions for associated production of a single top quark with a W boson or a charged Higgs boson. The calculation uses expressions for the massive cusp anomalous dimension, which are presented in different forms, and it allows soft-gluon resummation at next-to-next-to-leading-logarithm (NNLL) accuracy. From the NNLL resummed cross section I derive approximate NNLO cross sections for bg→tW- and bg→tH- at LHC energies of 7, 10, and 14 TeV.

Effects Of High-Flux Neutron Beams On He-3 Cells Polarized In Situ With Spin-Exchange Optical Pumping, E. Babcock, S. Boag, M. Becker, W. C. Chen, T. E. Chupp, T. R. Gentile, Gordon L. Jones, A. K. Petukhov, T. Soldner, T. G. Walker

Articles

Polarized He-3 produced by spin-exchange optical pumping (SEOP) has potential as a neutron spin filter for polarization and polarization analysis in many neutron-scattering and neutron particle physics applications. The advantage of the SEOP method is its suitability for providing continuous stable polarization over the course of long experiments. However, we have discovered that exposure to high neutron flux leads to additional strong relaxation mechanisms in the optically polarized alkali-metal vapor used to polarize the He-3. At a neutron flux density of 4.7 x 10(9) cm(-2) s(-1), the alkali-metal relaxation rate increased from 100 to 1000 s(-1) leading to reduced alkali-metal …

Two-Loop Soft Anomalous Dimensions And Next-To-Next-To-Leading-Logarithm Resummation For Heavy Quark Production, Nikolaos Kidonakis

Faculty and Research Publications

I present results for two-loop soft anomalous dimensions for heavy quark production which control soft-gluon resummation at next-to-next-to-leading-logarithm accuracy. I derive an explicit expression for the exact result and study it numerically for top quark production via e(+) e(-) -> t (t) over bar t, and I construct a surprisingly simple but very accurate approximation. I show that the two-loop soft anomalous dimensions with massive quarks display a simple proportionality relation to the one-loop result only in the limit of vanishing quark mass. I also discuss the extension of the calculation to single top and top pair production in hadron …

Electroproduction Of P Π⁺Π⁻ Off Protons At 0.2 < Q² < 0.6 Gev² And 1.3 < W < 1.57 Gev With The Clas Detector, M. J. Amaryan, H. Baghdasaryan, M. Bektasoglu, S. Bültmann, S. L. Careccia, G. E. Dodge, G. Gavalian, N. Guler, C. E. Hyde, W. Kim, A. Klein, F. J. Klein, A. Klimenko, S. E. Kuhn, S. Tkachenko, L. B. Weinstein, Et Al., Clas Collaboration

Physics Faculty Publications

This paper reports on the most comprehensive data set obtained on differential and fully integrated cross sections for the process ep → e'pπ⁺π^-. The data were collected with the CLAS detector at Jefferson Laboratory. Measurements were carried out in the as yet unexplored kinematic region of photon virtuality 0.2 < Q² < 0.6 GeV² and invariant mass of the final hadron system W from 1.3 to 1.57 GeV. For the first time, nine independent one-fold differential cross sections were determined in each bin of W and Q² covered by the measurements. A phenomenological analysis of the data allowed …

Theoretical Top Quark Cross Section At The Fermilab Tevatron And The Cern Lhc, Nikolaos Kidonakis, Ramona Vogt

Faculty and Research Publications

We present results for the top quark pair cross section at the Tevatron and the LHC. We use the resummed double differential cross section, employing the fully kinematics-dependent soft-anomalous-dimension matrices, to calculate the soft-gluon contributions at next-to-next-to-leading order (NNLO). We improve and update our previous estimates by refining our methods, including further subleading terms, and employing the most recent parton distribution function sets. The NNLO soft corrections significantly enhance the NLO cross section while considerably reducing the scale dependence. We provide a detailed discussion of all theoretical uncertainties in our calculation, including kinematics, scale, and parton distribution uncertainties, and clarify …

High-Efficiency Resonant Rf Spin Rotator With Broad Phase Space Acceptance For Pulsed Polarized Cold Neutron Beams, P.-N. Seo, L. Barron-Palos, J. D. Bowman, T. E. Chupp, C. Crawford, M. Dabaghyan, M. Dawkins, S. J. Freedman, T. Gentile, M. T. Gericke, R. C. Gillis, G. L. Greene, F. W. Hersman, Gordon L. Jones, M. Kandes, S. Lamoreaux, B. Lauss, M. B. Leuschner, R. Mahurin, M. Mason, J. Mei, G. S. Mitchell, H. Nann, S. A. Page, S. I. Penttila, W. D. Ramsay, A. Salas Bacci, S. Santra, M. Sharma, T. B. Smith, W. M. Snow, W. S. Wilburn, H. Zhu

Articles

High precision fundamental neutron physics experiments have been proposed for the intense pulsed spallation neutron beams at JSNS, LANSCE, and SNS to test the standard model and search for new physics. Certain systematic effects in some of these experiments have to be controlled at the few ppb level. The NPDGamma experiment, a search for the small parity-violating gamma-ray asymmetry A(gamma) in polarized cold neutron capture on parahydrogen, is one example. For the NPDGamma experiment we developed a radio-frequency resonant spin rotator to reverse the neutron polarization in a 9.5 cm x 9.5 cm pulsed cold neutron beam with high efficiency …

Experimental Study Of Exclusive ²H(E,E'P)N Reaction Mechanisms At High Q², S. E. Kuhn, M. J. Amaryan, H. Bagdasaryan, M. Bektasoglu, S. L. Careccia, K. V. Dharmawardane, G. E. Dodge, N. Guler, C. E. Hyde-Wright, H. G. Juengst, N. Kalantarians, A. Klein, M. R. Niroula, R. A. Niyazov, S. Tkachenko, L. B. Weinstein, J. Zhang, Et. Al., Clas Collaboration

Physics Faculty Publications

The reaction ²H(e,e(')p)n has been studied with full kinematic coverage for photon virtuality 1.75 < Q²< 5.5 GeV². Comparisons of experimental data with theory indicate that for very low values of neutron recoil momentum (p_n< 100 MeV/c) the neutron is primarily a spectator and the reaction can be described by the plane-wave impulse approximation. For 100 < p_n< 750 MeV/c, proton-neutron rescattering dominates the cross section, while Delta production followed by the NΔ → NN transition is the primary contribution at higher momenta.

Upper Bounds On Parity-Violating Gamma-Ray Asymmetries In Compound Nuclei From Polarized Cold Neutron Capture, M. T. Gericke, J. D. Bowman, R. D. Carlini, T. E. Chupp, K. P. Coulter, M. Dabaghyan, M. Dawkins, D. Desai, S. J. Freedman, T. R. Gentile, R. C. Gillis, G. L. Greene, F. W. Hersman, T. Ino, Gordon L. Jones, M. Kandes, B. Lauss, M. Leuschner, W. R. Lozowski, R. Mahurin, M. Mason, Y. Masuda, G. S. Mitchell, S. Muto, H. Nann, S. A. Page, S. I. Penttila, W. D. Ramsay, S. Santra, P.-N. Seo, E. I. Sharapov, T. B. Smith, W. M. Snow, W. S. Wilburn, V. Yuan, H. Zhu

Articles

Parity-odd asymmetries in the electromagnetic decays of compound nuclei can sometimes be amplified above values expected from simple dimensional estimates by the complexity of compound nuclear states. Using a statistical approach, we estimate the root-mean-square of the distribution of expected parity-odd correlations (s) over right arrow (n)center dot(k) over right arrow (gamma), where (s) over right arrow (n) is the neutron spin and (k) over right arrow (gamma) is the momentum of the gamma, in the integrated gamma spectrum from the capture of cold polarized neutrons on Al, Cu, and In. We present measurements of the asymmetries in these and …

Η’ Photoproduction On The Proton For Photon Energies From 1.527 To 2.227 Gev, M. Bektasoglu, S.L. Careccia, K. V. Dharmawardane, G. E. Dodge, C. E. Hyde-Wright, H. G. Juengst, A. Klein, S. E. Kuhn, A. V. Klimenko, L. M. Qin, F. Sabatié, S. Tkachenko, L. B. Weinstein, J. Yun, J. Zhang, Et Al., Clas Collaboration

Physics Faculty Publications

Differential cross sections for the reaction γp→η′p have been measured with the CLAS spectrometer and a tagged photon beam with energies from 1.527 to 2.227 GeV. The results reported here possess much greater accuracy than previous measurements. Analyses of these data suggest for the first time the coupling of the η′N channel to both the S₁₁(1535) and P₁₁(1710) resonances, known to couple strongly to the ηN channel in photoproduction on the proton, and the importance of J=3/2 resonances in the process.

Erratum: Η' Photoproduction On The Proton For Photon Energies From 1.527 To 2.227 Gev (Phys. Rev. Lett. 96, Pg 062001, 2006), H. Bagdasaryan, M. Bektasoglu, S. L. Careccia, K. V. Dharmawardane, G. E. Dodge, C. E. Hyde-Wright, A. Klein, S. E. Kuhn, L. M. Qin, F. Sabatié, L. B. Weinstein, Et Al., Clas Collaboration

Physics Faculty Publications

No abstract provided.

Polarized He-3 Gas Compression System Using Metastability-Exchange Optical Pumping, D. S. Hussey, D. R. Rich, A. S. Belov, X. Tong, H. Yang, C. Bailey, C. D. Keith, J. Hartfield, G. D. R. Hall, T. C. Black, W. M. Snow, T. R. Gentile, W. C. Chen, Gordon L. Jones, Eileen Wildman '01

Articles

Dense samples (10-100 bar cm) of nuclear spin polarized He-3 are utilized in high energy physics, neutron scattering, atomic physics, and magnetic resonance imaging. Metastability exchange optical pumping can rapidly produce high He-3 polarizations (&AP; 80%) at low pressures (few mbar). We describe a polarized He-3 gas compressor system which accepts 0.26 bar l h(-1) of He-3 gas polarized to 70% by a 4 W neodymium doped lanthanum magnesium hexaluminate (Nd:LMA) laser and compresses it into a 5 bar cm target with final polarization of 55%. The spin relaxation rates of the system's components have been measured using nuclear magnetic …

Beam-Helicity Asymmetries In Double-Charged-Pion Photoproduction On The Proton, H. Bagdasaryan, M. Bektasoglu, S. Bültmann, Gail Dodge, N. Guler, C. E. Hyde-Wright, H. G. Juengst, A. Klein, S. E. Kuhn, L. M. Qin, W. Roberts, F. Sabatié, S. Tkachenko, L. B. Weinstein, J. Yun, J. Zhang, Et Al., Clas Collaboration

Physics Faculty Publications

Beam-helicity asymmetries for the two-pion-photoproduction reaction 𝛾⃗p → p π⁺π^- have been studied for the first time in the resonance region for center-of-mass energies between 1.35 and 2.30 GeV. The experiment was performed at Jefferson Lab with the CEBAF Large Acceptance Spectrometer using circularly polarized tagged photons incident on an unpolarized hydrogen target. Beam-helicity-dependent angular distributions of the final-state particles were measured. The large cross-section asymmetries exhibit strong sensitivity to the kinematics and dynamics of the reaction. The data are compared with the results of various phenomenological model calculations, and show that these models currently do not …

Emit: An Apparatus To Test Time Reversal Invariance In Polarized Neutron Decay, H. P. Mumm, A. Garcia, L. Grout, M. Howe, L. P. Parazzoli, R. G. H. Robertson, K. M. Sundqvist, J. F. Wilkerson, S. J. Freedman, B. K. Fujikawa, L. J. Lising, M. S. Dewey, J. S. Nico, A. K. Thompson, T. E. Chupp, R. L. Cooper, K. P. Coulter, S. R. Hwang, R. C. Welsh, L. J. Broussard, C. A. Trull, F. E. Wietfeldt, Gordon L. Jones

Articles

We describe an apparatus used to measure the triple-correlation term (D (σ) over cap (n).p(e)xp(nu)) in the beta decay of polarized neutrons. The D coefficient is sensitive to possible violations of time reversal invariance. The detector has an octagonal symmetry that optimizes electron-proton coincidence rates and reduces systematic effects. A beam of longitudinally polarized cold neutrons passes through the detector chamber, where a small fraction undergo beta decay. The final-state protons are accelerated and focused onto arrays of cooled semiconductor diodes, while the coincident electrons are detected using panels of plastic scintillator. Details regarding the design and performance of the …

Neutron Cross Sections For He-3 At Epithermal Energies, C. D. Keith, Z. Chowdhuri, D. R. Rich, W. M. Snow, J. D. Bowman, S. L. Penttila, D. A. Smith, M. B. Leuschner, V. R. Pomeroy, Gordon L. Jones, E. I. Sharapov

Articles

High accuracy, absolute measurements of the neutron total cross section for He-3 are reported for incident neutron energies 0.1-400 eV. The measurements were performed at the LANSCE short-pulse neutron spallation source. Using the previously determined cross section for neutron elastic scattering, 3.367+/-0.019 b, we extract a new value for the energy dependence of the He-3(n,p)He-3 reaction cross section, sigma(np)=(849.77+/-0.14+/-1.02)E-1/2-(1.253+/-0.00+/-(+0.008)(-0.049))b, where the neutron energy is expressed in eV. The first uncertainty is statistical, the second systematic.

Measurement Of The Electric Form Factor Of The Neutron At Q² = 0.5 And 1.0 Gev²/C², Jefferson Lab E93-026 Collaboration, G. Warren, F. Wesselmann, H. Zhu, A. Klimenko, S. E. Kuhn, L. Yuan, J. Yun, B. Zihlmann, Et Al.

Physics Faculty Publications

The electric form factor of the neutron was determined from measurements of the ^→d( ^→e, e'n)p reaction for quasielastic kinematics. Polarized electrons were scattered off a polarized deuterated ammonia (¹⁵ND₃) target in which the deuteron polarization was perpendicular to the momentum transfer. The scattered electrons were detected in a magnetic spectrometer in coincidence with neutrons in a large solid angle detector. We find Gⁿ_E =0.0526 ± 0.0033(stat) ± 0.0026(sys) and 0.0454 ± 0.0054 ± 0.0037 at Q²=0.5 and 1.0 (GeV/c)², respectively.

Ep → Ep Π⁰ Reaction Studied In The Δ(1232) Mass Region Using Polarization Asymmetries, M. Bektasoglu, L. Ciciani, K.V. Dharmawardane, G. E. Dodge, T.A. Forest, C.E. Hyde-Wright, A. Klein, A. V. Klimenko, S. E. Kuhn, S. Stepanyan, L. B. Weinstein, Et Al., Clas Collaboration

Physics Faculty Publications

Measurements of the angular distributions of target and double-spin asymmetries for the Δ⁺(1232) in the exclusive channel ^→ p(^→e,e'p)π⁰ obtained at the Jefferson Lab in the Q² range from 0.5 to 1.5 GeV²/c² are presented. Results of the asymmetries are compared with the unitary isobar model [D. Drechsel , Nucl. Phys. A645, 145 (1999)], dynamical models [T. Sato and T. S. Lee, Phys. Rev. C 54, 2660 (1996); S. S. Kamalov , Phys. Lett. B 27, 522 (2001)], and the effective Lagrangian theory [R. M. Davidson , Phys. Rev. …

First Measurement Of Transferred Polarization In The Exclusive →E P → E'K+ →Λ, M. Bektasoglu, K. V. Dharmawardane, G. E. Dodge, T. A. Forest, C. E. Hyde-Wright, A. V. Klimenko, S. E. Kuhn, R. A. Niyazov, L. M. Qin, L. B. Weinstein, J. Yun

Physics Faculty Publications

The first measurements of the transferred polarization for the exclusive ^→ep → e'K+ ^→Λ over right arrow reaction have been performed at Jefferson Laboratory using the CLAS spectrometer. A 2.567 GeV beam was used to measure the hyperon polarization over Q² from 0.3 to 1.5 (GeV/c)², W from 1.6 to 2.15 GeV, and over the full K⁺ center-of-mass angular range. Comparison with predictions of hadrodynamic models indicates strong sensitivity to the underlying resonance contributions. A nonrelativistic quark-model interpretation of our data suggests that the s ^-s quark pair is produced with spins predominantly …

Measurement Of Parity-Nonconserving Rotation Of Neutron Spin In The 0.734-Ev P-Wave Resonance Of La-139, T. Haseyama, K. Asahi, J. D. Bowman, P. P. J. Delheij, H. Funahashi, S. Ishimoto, Gordon L. Jones, A. Masaike, Y. Masuda, Y. Matsuda, K. Morimoto, S. Muto, S. I. Penttila, V. R. Pomeroy, K. Sakai, E. I. Sharapov, D. A. Smith, V. W. Yuan

Articles

The parity nonconserving spin rotation of neutrons in the 0.734-eV p-wave resonance of La-139 was measured with the neutron transmission method. Two optically polarized He-3 cells were used before and behind a 5-cm long La-139 target, each as a polarizer and an analyzer for neutron spin. The rotation angle was carefully measured by flipping the direction of He-3 polarization in the polarizer in sequence. The peak-to-peak value of the spin rotation was determined to be (7.4+/-1.1) x 10(-3) rad/cm. The result is found to be consistent with the previous experiments, but the result was statistically improved. The s-p mixing model …

Publisher's Note: Η Photoproduction On The Proton For Photon Energies From 0.75 To 1.95 Gev [Phys. Rev. Lett. 89, 222002 (2002)], M. Bektasoglu, K. V. Dharmawardane, G. E. Dodge, C. E. Hyde-Wright, A. Klein, S. E. Kuhn, R. A. Niyazov, S. Stepanyan, L. B. Weinstein, Et Al., Clas Collaboration

Physics Faculty Publications

No abstract provided.

Η Photoproduction On The Proton For Photon Energies From 0.75 To 1.95 Gev, M. Bektasoglu, K. V. Dharmawardane, G. E. Dodge, C. E. Hyde-Wright, A. Klein, S. E. Kuhn, S. Stepanyan, J. Yun, Et Al., Clas Collaboration

Physics Faculty Publications

Differential cross sections for γp→ηp have been measured with tagged real photons for incident photon energies from 0.75 to 1.95 GeV. Mesons were identified by missing mass reconstruction using kinematical information for protons scattered in the production process. The data provide the first extensive angular distribution measurements for the process above W = 1.75  GeV. Comparison with preliminary results from a constituent quark model support the suggestion that a third S₁₁ resonance with mass ∼1.8  GeV couples to the ηN channel.

New Limit On The D Coefficient In Polarized Neutron Decay, L. J. Lising, S. R. Hwang, J. M. Adams, T. J. Bowles, M. C. Browne, T. E. Chupp, K. P. Coulter, M. S. Dewey, S. J. Freedman, B. K. Fujikawa, A. Garcia, G. L. Greene, Gordon L. Jones, H. P. Mumm, J. S. Nico, J. M. Richardson, R. G. H. Robertson, T. D. Steiger, W. A. Teasdale, A. K. Thompson, E. G. Wasserman, F. E. Wietfeldt, R. C. Welsh, J. F. Wilkerson

Articles

We describe an experiment that has set new limits on the time reversal invariance violating D coefficient in neutron beta decay. The emiT experiment measured the angular correlation [J] . (p(e) x p(p)) using an octagonal symmetry that optimizes electron-proton coincidence rates. The result is D=[-0.6+/-1.2(stat)+/-0.5(syst)] x 10(-3). This improves constraints on the phase of g(A)/g(V) and limits contributions to T violation due to leptoquarks. This paper presents details of the experiment, data analysis, and the investigation of systematic effects.

Sans Polarization Analysis With Nuclear-Spin-Polarized He-3, T. R. Gentile, Gordon L. Jones, A. K. Thompson, J. Barker, C. J. Glinka, B. Hammouda, J. W. Lynn

Articles

A neutron spin filter based on transmission through nuclear-spin-polarized He-3 gas has been applied to polarization analysis of small angle neutron scattering (SANS). Such spin filters, which are based on the large spin dependence of the absorption of neutrons by He-3, make SANS polarization analysis possible because of their large angular acceptance. In the present experiment, a He-3-based analyzer was employed to separate nuclear scattering into its coherent and spin-incoherent components. Polarized He-3 analyzers were prepared by two different optical pumping methods and installed on the NG3 SANS instrument at the NIST Center for Neutron Research (NCNR). Measurements were taken …

Inclusive Electron Scattering From Nuclei At X≃1, J. Arrington, P. Anthony, R. G. Arnold, E. J. Beise, J. E. Belz, P. E. Bosted, H.- J. Bulten, M. S. Chapman, K. P. Coulter, F. Dietrich, R. Ent, M. Epstein, B. W. Filippone, H. Gao, R. A. Gearhart, D. F. Geesaman, J.- O. Hansen, R. J. Holt, H. E. Jackson, C. E. Jones, C. E. Keppel, E. R. Kinney, S. Kuhn, K. Lee, W. Lorenzon, A. Lung, N.C.R. Malkins, D. J. Margaziotis, R. D. Mckeown, R. G. Milner, B. Mueller, J. Napolitano, J. Nelson, T.G. O'Neill, V. Papavassiliou, G. G. Petratos, D. H. Potterveld, S. E. Rock, M. Spengos, Z. M. Szalata, L. H. Tao, K. Van Bibber, J.F.J. Van Den Brand, J. L. White, D. Winter, B. Zeidman

Physics Faculty Publications

The inclusive A(e,e') cross section for x≃1 was measured on ²H, C, Fe, and Au for momentum transfers Q² from 1 to 6.8 (GeV/c)². The scaling behavior of the data was examined in the region of transition from y scaling to x scaling. Throughout this transitional region, the data exhibit ξ scaling, reminiscent of the Bloom-Gilman duality seen in free nucleon scattering.

Laser Oriented K-36 For Time-Reversal Symmetry Measurements, A. R. Young, W. S. Anderson, F. P. Calaprice, G. D. Cates, Gordon L. Jones, D. A. Krieger, R. B. Vogelaar

Articles

We have produced very large nuclear alignments in radioactive K-36 (half-life 0.34 sec) through laser optical pumping techniques. The K-36 was created through (p,n) reactions using a 50 nA, 22 MeV proton beam, and a 3.3 atmosphere Ar-36 target. Measurements were made with the target cell at room temperature, when direct optical pumping produces nuclear orientation in the K-36, and at elevated temperatures 160 degrees C and 180 degrees C) where the K-36 is oriented through a combination of direct optical pumping and spin exchange. The fraction of the maximal nuclear alignment for the 180 degrees C data was determined …