Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
- Institution
- Keyword
-
- Physics (4)
- Electron (3)
- Laser (2)
- Light (2)
- Magneto-Optical Trap (2)
-
- Resonance (2)
- Rubidium (2)
- Rydberg (2)
- Rydberg Atoms (2)
- Particles (Nuclear physics) (1)
- Afm (1)
- Alignment System (1)
- Annihilation (1)
- Atom (1)
- Atom Trapping (1)
- Atomic Density (1)
- Atomic spectroscopy (1)
- AuNP (1)
- Beta particles (1)
- Biography (1)
- Biophysics (1)
- CLAS12 Detector (1)
- Chloride (1)
- Coherence (1)
- Compensator (1)
- Computational (1)
- Concerted (1)
- Core Polarizability (1)
- Core-Conversion (1)
- Diffraction (1)
- Publication Year
- Publication Type
Articles 1 - 28 of 28
Full-Text Articles in Physical Sciences and Mathematics
Study Of Missing Mass Background In The Clas12 Detector, Jessie Hess, Gerard P. Gilfoyle, Lamya Baashen
Study Of Missing Mass Background In The Clas12 Detector, Jessie Hess, Gerard P. Gilfoyle, Lamya Baashen
Honors Theses
At Jefferson Lab we use the CLAS12 detector to measure the neutron magnetic form factor. An accurate measurement of the CLAS12 neutron detection efficiency (NDE) is required. We use the nuclear reaction ���� → ��′��+�� as a source of tagged neutrons and obtain the NDE from the ratio of expected neutrons to detected ones. We assume the final state consists of ��′��+�� only, use the ��′��+ information to predict the neutron's position(expected) and then search for that neutron(detected). We select neutrons with the missing mass (MM) technique. We use simulation to validate our methods. We simulated events with the Monte-Carlo …
Detecting High-Lying Rydberg States Using Two-Step Electromagnetically Induced Transparency And Frequency Modulation Spectroscopy Techniques, Kate Jensen
Honors Theses
Resonant optical excitation of high-lying Rydberg states in room temperature 85Rb was investigated using light from two homemade external cavity diode lasers (ECDL). This was done using a ladder schema of the Electromagnetically Induced Transparency (EIT) technique. The approximate EIT wavelengths used were 780 nm (the probe beam) to provide step-wise excitation of valence rubidium electrons from the 5S1/2 → 5P3/2 tran- sition, and then 482 nm (the coupling beam) to excite from the 5P3/2 state to a high-lying Rydberg nD state with an orbital angular momentum = 2. Successful excitation of the Rydberg states was observed using Frequency Modulation …
External Beam Alignment System For Quantitative Proton Induced Gamma-Ray Emission (Pige) Spectroscopy, Elias Ottens
External Beam Alignment System For Quantitative Proton Induced Gamma-Ray Emission (Pige) Spectroscopy, Elias Ottens
Honors Theses
The effects of pollution on the ecosystem are paramount in our society, permeating air, soil, and drinking water. One contaminant of concern is per- and polyfluoroalkyl substances (PFAS), also referred to as "forever chemicals", which contains fluorine (F), a potentially harmful element to humans. To investigate pollution in the environment, it is necessary to make accurate measurements of the distribution and concentrations of these PFAS chemicals. To do this, soil samples are collected and analyzed using Particle Induced Gamma-ray Emission (PIGE) via the Union College Ion Beam Analysis Laboratory's (UCIBAL) particle accelerator. A 2.2 MeV proton beam comes into contact …
Lifetime Measurement Of The Xi_C^+ Using Belle Ii Monte Carlo, Paul Gebeline
Lifetime Measurement Of The Xi_C^+ Using Belle Ii Monte Carlo, Paul Gebeline
Honors Theses
This analysis uses simulated data from the Belle II experiment to measure the lifetime of the Xi_c^+ baryon. Three different decay modes are investigated to explore the feasibility and accuracy of such measurements at Belle II. The Xi_c^+ lifetime is measured using one of these modes after reducing backgrounds from sources other than the decay of interest. The final result is 464 +/- 15 fs, which is consistent with the expected result of 442 fs within uncertainty. This result shows that Belle II can make competitive measurements of particle properties and decays.
Electron-Positron Annihilation Lifetime Spectroscopy Of Mgo And Aluminum-Doped Mgo, Elise Liebow
Electron-Positron Annihilation Lifetime Spectroscopy Of Mgo And Aluminum-Doped Mgo, Elise Liebow
Honors Theses
Radiation is a form of energy that can damage materials at an atomic level. This has implications for the mobility of radioactive waste through containment materials. We are characterizing atomic defects in materials by using Electron-Positron Annihilation Lifetime Spectroscopy (EPALS). When an electron and positron come into contact with each other, they annihilate and release two antiparallel 511-keV gamma rays. In a pristine crystalline sample, positrons can easily annihilate with electrons, but in a sample with vacancies/defects in the crystal structure, positrons take longer to annihilate. Therefore, the more vacancies in a sample, the longer the average lifetime of a …
Apparatus Improvement And Characterisation For Experiments On Ultra-Cold Plasmas., Jakub Bystrický
Apparatus Improvement And Characterisation For Experiments On Ultra-Cold Plasmas., Jakub Bystrický
Honors Theses
Apparatus for creating ultra-cold neutral plasmas (UNPs) was improved and data on plasma expansion was collected. We increase the trapping efficiency of a quadrupole magneto-optical trap (MOT) by installing a tapered amplifier to increase the power of the cooling laser used to trap atoms. We achieve an improvement in density of trapped atoms from 1 x 1010 cm-3 to 2.5 - 4.5 x 1010 cm-3. In addition, to improve precision and decrease systematic error, the magnetic field induced by inductive current in the MOT's anti-helmholtz coils was suppressed. This was achieved by installing a KEPCO …
A Theoretical Study Of Synchronous Proton Transfer In (Hf)N, (H2O) N, And (Hcl) N Where N = 3, 4, 5, Johnny Yang
A Theoretical Study Of Synchronous Proton Transfer In (Hf)N, (H2O) N, And (Hcl) N Where N = 3, 4, 5, Johnny Yang
Honors Theses
For (HF)n, (H2O)n, and (HCl)n (n = 3 − 5), we have rigorously characterized the structures for the minima and transition states for synchronous proton transfer (SPT) with the CCSD(T) method and aug-cc-pVTZ basis set. The electronic barrier heights (∆E†) associated with these transition states have also been computed with the explicitly correlated CCSD(T)-F12 method and the aug-cc-pVQZ-F12 basis set (abbreviated aQZ-F12). (HCl)n (n = 3 − 5) SPT transition states have not been previously identified to the best of our knowledge, and they have been found …
Study Of Neon Collisional Negative Ion Compound Resonance Using A Trochoidal Electron Monochromator, Will Brunner
Study Of Neon Collisional Negative Ion Compound Resonance Using A Trochoidal Electron Monochromator, Will Brunner
Honors Theses
This thesis describes the experimental apparatus and procedure used to measure the excitation function of the 2p53p 3D3 state of neon. First I describe the effect on this excitation of negative ion resonances and previous experiments to measure the excitation function, as well as suggestions for future applications of such studies. Then the experimental apparatus is described in three parts. The vacuum system uses a turbomolecular pump to decrease the pressure of the chamber to as low as 4*10-9 Torr. The electron beam system incorporates a trochoidal electron monochromator to send a highly monochromatic beam …
Electron Beam Dispersion Compensator Using A Wien Filter, Jackson Lederer
Electron Beam Dispersion Compensator Using A Wien Filter, Jackson Lederer
Honors Theses
When an electron beam travels through space, it spreads out over time which impedes the ability to work with short electron pulses in the lab. A Wien filter is a device consisting of perpendicular electric and magnetic fields which filters charged particles based on their velocities. For a specific velocity, the two forces from the two fields in the filter cancel each other out letting charges with that velocity travel straight through the filter. Charges moving at other speeds are deflected as they have a net force applied to them from the filter. If a particle is deflected from the …
Mot-Based Lifetime Measurements Of Potassium-39 5p1/2 And 5p3/2 States, Huan Q. Bui
Mot-Based Lifetime Measurements Of Potassium-39 5p1/2 And 5p3/2 States, Huan Q. Bui
Honors Theses
This thesis presents measurements of the lifetimes of 5p1/2 and 5p3/2 of K39 via exciting a cloud of K39 atoms in a magneto-optical trap by a linearly-polarized pulse of 405 nm light followed polarization-specific, time-resolved fluorescence detection. We find that $\tau_{5p1/2} = $ 138.8 $\pm$ 1.6 ns, which is consistent with past measurements \cite{triumf}, \cite{berends} and calculations \cite{safranova}. The $\tau_{5p3/2}$ measurement is naturally more involved since quantum beats due to hyperfine and Zeeman effect are present. Our observation of $\tau_{5p3/2} =$ 137.6 $\pm$ 3.1 ns and $\tau_{5p3/2} =$ 136.0 $\pm$ 2.4 ns, obtained from two slightly different approaches, are compared …
Comparison Of The Vibrational Modes Of Thiolated Gold Nanoparticles Undergoing Core-Conversions Via Raman Spectroscopy, William Gregory Cannella Jr.
Comparison Of The Vibrational Modes Of Thiolated Gold Nanoparticles Undergoing Core-Conversions Via Raman Spectroscopy, William Gregory Cannella Jr.
Honors Theses
In this project, the vibrational characteristics/vibrational modes are explored via Raman Spectroscopy for thiolated-gold nanoparticles. This class of compounds is also known as gold nanoparticles (AuNPs). They remain of great interest in research areas such as catalysis, gold dependent nanoelectronics, drug delivery, and sensing, due to their unique size-dependent optical, chiroptical, and electronic properties. Vibrational spectroscopy of thiolated gold nanoparticles are oftentimes considered nontrivial as the compounds strongly absorb light in the visible region of the electromagnetic spectrum, are generally considered weak scatterers, and give off large amounts of fluorescence. This combined with their black appearance, susceptibility to localized heating, …
Characterization Of A Trochoidal Electron Monochromator, Jesse Kruse
Characterization Of A Trochoidal Electron Monochromator, Jesse Kruse
Honors Theses
This thesis presents a quantitative study of a trochoidal electron monochromator and attempts to observe the 2p^53p^2 resonance in neon. A detailed description of the experimental apparatus, including the electron beam system, the vacuum system, and the light analysis system, is presented first. Then, we discuss the theory of how the electron beam is monochromatized, how we measured monochomatization, and how we analyze the light being emitted from the collision cell. The light analysis system is capable of accurately measuring the relative Stokes parameters for any polarization of light, and the electron beam system is capable of producing electron beams …
Quantum Defect Measurements For High Angular Momentum Rydberg States Of Potassium, Abraham Hill
Quantum Defect Measurements For High Angular Momentum Rydberg States Of Potassium, Abraham Hill
Honors Theses
We report measurements of the quantum defect for the f-, g-, and h-states of potassium with principal quantum number n between 26 and 29. Ground state potassium atoms in a magneto-optical trap are excited from the 4s state to the 5p state, then from the 5p state to the ndj state using lasers at 405nm and 980nm, respectively. We then measure the millimeter wave frequencies of the ndj to nl transitions. We extract the quantum defects from these frequency measurements in conjunction with the known d-state quantum defects. Experimental challenges with …
Expansion Of An Ultracold Neutral Plasma, Yin Li
Expansion Of An Ultracold Neutral Plasma, Yin Li
Honors Theses
Ultracold neutral plasmas (UNP) exhibit interesting behavior and are more feasible to control than hot plasmas. Physicists would like to lower the temperature of a UNP to achieve a higher Coulomb coupling parameter, Γ for both electrons and ions. However, the three body recombination (TBR) between ions and electrons produces Rydberg atoms and heats up the plasma electrons, thereby ionizing them to Γe < 0.2. Adding Rydberg atoms to the plasma will reduce the temperature of a UNP in certain situations. In this honors project, we tried to achieve a Γe value greater than 0.5 by embedding Rydberg atoms multiple times in the plasma. We did extensive numerical simulations, but we were unable to replicate previous results from another group which obtained Γe = 0.5 in the first 1 µ s of plasma evolution. However, we were able to use the simulation results to test various different experiment scenarios. For experiments, we created a UNP of Rubidium atoms in the magneto-optical trap by laser cooling and photoionization. We figured out a nice way to zero the electric field within the field meshes by looking at the plasma expansion very late in its evolution through the micro-channel plate. We set the voltage and delay on the field mesh bias to find expansion velocity of the plasma for time t > 50 µs, and we used different methods to deduce the expansion velocity from the ion time of flight signals. However, we found that there was no relation of Γe at 1 µ s and the expansion velocity …
Ion-Beam Analysis Of Artificial Turf, Morgan Clark
Ion-Beam Analysis Of Artificial Turf, Morgan Clark
Honors Theses
There have been considerable concerns in recent years that artificial turf used in many playing fields around the world may be unsafe. While the presence of heavy metals and carcinogenic chemicals have been reported in a number of studies more data and research are needed to determine if there is a real link between artificial turf and adverse health effects. We performed PIXE and PIGE analysis of artificial turf blade and infill samples to search for heavy metals and other possibly toxic substances. The samples were bombarded with proton beams from the 1.1-MV Pelletron tandem accelerator in the Union College …
Atomic Force Microscopy Of Poly(Ethylane-Oxide) Crystalization, Xavier Capaldi
Atomic Force Microscopy Of Poly(Ethylane-Oxide) Crystalization, Xavier Capaldi
Honors Theses
Polymer crystallization is a complex process which is influenced by a variety of factors. Atomic force microscopy is used to explore the material properties of polymer crystals. Poly(ethylene-oxide) is used in a variety of molecular weights as the sample. In addition, a variety of sample preparation methods and microscopy modes were tested. A relatively new imaging technique was identified for the characterization of polymer crystals: amplitude modulation-frequency modulation viscoelastic mapping. This mode was used to measure material properties such as stiffness and dissipation.
Resonant Collisions Of Potassium Atoms, Philip Michael Adamson
Resonant Collisions Of Potassium Atoms, Philip Michael Adamson
Honors Theses
This thesis discusses an approach to excite potassium atoms to very highly excited states (Rydberg states), and then tune their energy levels to induce resonant collisions between atoms. Potassium gas is super-cooled to 1 mK and confined to a small volume in a magneto-optical trap. A 405 nm laser diode, electronically locked to a potassium vapor cell via Doppler free spectroscopy, excites these atoms from the 4s1/2 state (ground state) to the 5p3/2 state. A 978 nm laser then excites the 5p3/2 to nd3/2 or nd5/2 transition, creating Rydberg atoms. Since there is no ground …
Construction And Optimization Of A Tapered Amplifier System For Applications In Ultra-Cold Plasma Research, Ryan Cole
Honors Theses
The number density of cold atoms confined in a magneto-optical trap (MOT) is critically dependent on the intensity of the lasers used to cool the sample. To generate large optical powers while retaining the practicality of homemade external cavity diode lasers (ECDLs), a tapered amplifier (TA) system was designed and constructed to amplify the output of an existing 780 nm, continuous-wave ECDL. The amplifier’s performance is discussed in terms of its gain and power output. Under standard operating conditions, optical amplification of 12 dB is achieved, with a maximum power output of 0.75 W. The completed amplifier is installed into …
Quantumness And Coherence In Photosynthesis, Brian Doolittle
Quantumness And Coherence In Photosynthesis, Brian Doolittle
Honors Theses
Long-lived oscillations lasting up to 1800 fs have been observed in the Fenna--Mathews--Olsen (FMO) Pigment-Protein complex. It is unclear if the oscillations are quantum or classical in origin. Quantized intra-pigment normal modes are responsible for these long-lived oscillations. In this thesis we simulate a bacteriachlorophyll dimer in the FMO Complex at physiological conditions. Our model describes two electronically coupled pigments coupled to the vibrational protein environment. Our goal is to find system parameters that allow long-lived quantum coherences to exist in photosynthetic complexes. We calculate the time evolution of our system's density matrix using the numerically exact quantum adiabatic path …
The Talbot Effect, Malia Kawamura
The Talbot Effect, Malia Kawamura
Honors Theses
The goal of this project is to experimentally investigate the optical Talbot effect and the electron Talbot effect. The Talbot effect is a near-field diffraction effect which occurs when plane waves are incident upon a grating. The Talbot effect creates full grating revivals at integral Talbot lengths and revivals with greater spatial periodicity at fractional Talbot lengths. We use a green helium neon laser and Ronchi rulings to take CCD camera images of the fractional Talbot revivals directly. Additionally, a photodiode records light intensity as a function of time as a second identical grating is moved to verify the presence …
Oxidation Resistance Studies Of Crain Coatings On 430 Stainless Steel, Kurtis Wickey
Oxidation Resistance Studies Of Crain Coatings On 430 Stainless Steel, Kurtis Wickey
Honors Theses
The requirements of low cost and high-cost temperature corrosion resistance for interconnect plates in solid oxide fuel cell stacks has directed attention to the use of metal plates with oxidation resistant coatings. We have investigated the performance of stainless steel plates with homogenous coatings of CrAIN. The coatings were deposited using RF magnetron sputtering, with Ar as a sputtering gas and N as reactive gas. The Cr/A1 composition ratio in the coatings was varied in a combinatorial approach. The coatings were subsequently annealed in air for up to 25 hours at 800°C. The composition of the coated plates and the …
Search For Novel Molecular Species Formed By Cold Rydberg Atoms In A Magneto-Optical Trap, Alexander Gill
Search For Novel Molecular Species Formed By Cold Rydberg Atoms In A Magneto-Optical Trap, Alexander Gill
Honors Theses
This describes a search for novel ultra-long-range molecular resonances between rubidium Rydberg atoms in a magneto-optical trap (MOT). We use the technique of photoassociative spectroscopy by directly scanning the wavelength of our Rydberg excitation laser about a 5p3/2 - 90p3/2 transition in a weak electric field and by scanning mm-waves about a 39sl/2 - 39p3/2 transition. The results of both of these surveys are inconclusive.
Diode Lasers For Use In Experiments On Cold Rydberg Atoms, Bill Whitledge
Diode Lasers For Use In Experiments On Cold Rydberg Atoms, Bill Whitledge
Honors Theses
This project was to measure the atomic density of (85)Rb atoms in a magneto optical trap using a low-intensity probe laser. Additionally, a dark spontaneous force optical trap was constructed in an attempt to boost the trap density. The dark spot failed to appreciably increase the overall trap density (which remained steady at - N = 10^10 atoms/cm^3) but it did increase the density of dark-state atoms in the trap by an order of magnitude. This is a useful result since many experiments on cold Rydberg atoms involve exciting atoms starting in the ground state rather than the first excited …
Angle-Resolved Study Of Ar 2p₁/₂,₃/₂⁻1Ns,D Resonant Auger Decay, Marc Andrew Humphrey
Angle-Resolved Study Of Ar 2p₁/₂,₃/₂⁻1Ns,D Resonant Auger Decay, Marc Andrew Humphrey
Honors Theses
Angle-resolved measurements of the Ar 2p1/2,3/2-14s,3d,4d and 2p3/2-14s,3d,4d resonant Auger transitions have been carried out using photons from an undulator beamline at the Advanced Light Source of Lawrence Berkeley National Laboratory. The intensity distributions and angular distribution anisotropy (β) parameters have been reported for nearly all of the possible 3p4nl final ionic states. These results further verify the predictions of the spectator model for the 2p1/2,3/2-14s resonances and the subsequent breakdown of this model for the 2p1/2,3/2-13d and 2p1/2,3/2-14d relative intensities. This work …
Design And Construction Of A Lithium Vapor Oven, Corey A. Leon
Design And Construction Of A Lithium Vapor Oven, Corey A. Leon
Honors Theses
A lithium vapor oven to be used as a source of lithium target atoms in atomic collision experiments was designed and constructed. The oven was installed in the beamline of the Van de Graaff accelerator at Western Michigan University. Test results indicated the oven produced a diffuse cloud of evaporated lithium instead of the intended concentrated jet spray. Recommendations concerning the design are made for future efforts.
Simulated Alpha Scattering, Gerald L. Fuller
Simulated Alpha Scattering, Gerald L. Fuller
Honors Theses
My approach to the experiment is to use a box of certain dimension as the Gold atom. This, I'm going to bombard with B.B's as alpha particles. Therefore this is a simulated alpha scattering experiment. The box is like unto the atom whereas shooting into it you cannot see what happens nor where it happens, but draw on your information taken while observe the effects outside the atom and the box likewise. A screen is used with the atom, and I have used a cardboard square placed in slats around my box to record the direction the particles enters and …
Polarization Of Compton-Scattered Gamma Rays, James G. Hudson
Polarization Of Compton-Scattered Gamma Rays, James G. Hudson
Honors Theses
Intermediate energy photons (approximately 0.2 mev. to 10 mev.) interact with matter of low atomic number principally through a process called the Compton effect. This process is an inelastic collision of a photon with a free electron at rest. Using the principles of conservation of energy and conservation of momentum the energy of the scattered photon can be found in terms of the incident photon energy and the angle through which it is scattered. The energy of this scattered photon is then given by E1=(EO)/(1+α(1-cos θ)) where EO is the energy of the incoming photon, …
Frederic Joliot-Curie And Atomic Energy By Pierre Biquard Pp. 109-211, Donald Printest Watkins
Frederic Joliot-Curie And Atomic Energy By Pierre Biquard Pp. 109-211, Donald Printest Watkins
Honors Theses
This is a translation of pages 109-211 of the biography Frederic Joliot-Curie Et L'energie Atomique by Pierre Biquard.