Physics: Posters

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A Measurement of the Muon Magnetic Moment Using Cosmic Rays
(Houghton College, 2001-11-03) Ely, David Richard; Kroening, Daniel Atkinson; Yuly, Mark
The muon magnetic moment is being measured via the decay of polarized cosmic-ray muons in a 44 G magnetic field. One, thick, 102.0 x 20.6 x 5.4 cm plastic scintillator detector was placed between two, 101.5 x 20.6 x 1.6 cm detectors in the uniform magnetic field produced by a solenoid. A veto-scintillator eliminated events from regions of non-uniform magnetic field. The time difference between when the muon stopped in the center detector and the detection of the decay positron was recorded for several thousand events. The decay positron is emitted along the direction of the precessing muon spin axis.
Rochester Academy of Science, 28th Annual Paper Session, Nazareth College, Rochester NY. November 3, 2001.
A New Evaporator for the Houghton College Deposition Chamber
(Houghton College, 2022-04-08) Bowman, Matthew; Hoffman, Brandon
XL Annual Rochester Symposium for Physics Students, University of Rochester, April 8, 2022.
A Phoswich Detector System to Measure Sub-Second Half-Lives using ICF Reactions
(Houghton College, 2017-10-23) Coats, Micah; Cook, Katelyn; Yuly, Mark; Padalino, Stephen; Sangster, Craig; Regan, Sean
The 3H(t,γ)6He cross section has not been measured at any bombarding energy due to the difficulties of simultaneously producing both a tritium beam and target at accelerator labs. An alternative technique may be to use an ICF tt implosion at the OMEGA Laser Facility. The 3H(t,γ)6He cross section could be determined in situ by measuring the beta decay of 6He beginning a few milliseconds after the shot along with other ICF diagnostics. A dE-E phoswich system capable of surviving in the OMEGA target chamber was tested using the SUNY Geneseo pelletron to create neutrons via 2H(d,n)3He and subsequently 6He via 9Be(n,α)6He in a beryllium target. The phoswich dE-E detector system was used to select beta decay events and measure the 807 ms halflife of 6He. It is composed of a thin, 2 ns decay time dE scintillator optically coupled to a thick, 285 ns E scintillator, with a linear gate to separate the short dE pulse from the longer E tail. Funded in part by a grant from the DOE through the Laboratory for Laser Energetics.
Omega Laser User’s Group Meeting, Laboratory for Laser Energetics, Rochester, NY, April 25, 2018; XXXVII Annual Rochester Symposium for Physics Students, SUNY Brockport, Brockport, NY., April 7, 2018; 59th Annual Meeting of the APS Division of Plasma Physics, Milwaukee, WI, Oct. 23-27, 2017; 2017 APS Division of Plasma Physics Outstanding Undergraduate Poster Award; 2018 Omega Laser Facility Users Group Workshop Student Poster Award.
A possible 12C(n,2n)11C total cross section measurement
(Houghton College, 2011-11-14) Evans, Andrew; Mann, Keith; Yuly, Mark
Tertiary neutron production can be used as an indicator of the burn fraction of a deuterium-tritium pellet in inertial confinement fusion reactions. One way to monitor tertiary neutrons is by carbon activation using the 12C(n,2n)11C reaction, which has a threshold of 20.3 MeV and so is insensitive to primary neutrons produced in the DT reaction. However, the cross section for this reaction is not well known. Several different experimental techniques for measuring 12C(n,2n) have been examined, with an activation experiment being the most feasible.
XXXI Annual Rochester Symposium for Physics Students, Siena College, Loudonville, NY, April 14, 2012; 53rd Annual Meeting of the APS Division of Plasma Physics, Salt Lake City, Utah, November 14-18, 2011.
A Study of Weak Magnetic Focusing
(Houghton College, 2014-04-05) Morrow, Sylvia; Yuly, Mark
The small cyclotron at Houghton College loses at least 80% of the beam due to collisions with the dees and chamber walls. Weak magnetic focusing is being studied as a technique to reduce this problem by altering the magnetic field, which is currently nearly uniform, to create a greater radial magnetic field component which will create a restoring force to return ions to the central orbit plane. A computer model of the magnet and chamber is being to developed to design magnet shims that will give the most advantageous magnetic field shape for good focusing. A two dimensional cross section of the magnet has been modeled using Poisson Superfish, the results of which were used to track ions with the Simion 8.0 code. The model can be used to simulate various options for shim sizes and configurations the results of which will determine which shims will eventually be tested. Results of the computer model were compared with analytical results using a simplified model.
XXXIII Annual Rochester Symposium for Physics Students, University of Rochester, Rochester, NY., April 5, 2014; Penn-York Undergraduate Research Association Conference, Houghton College, Houghton, NY 14744. Nov. 1, 2014.
A Temperature Control Stage for Deposition of Thin Metal Films
(Houghton University, 2023-04-15) Fall, Owen; Yelle, Luke; Hoffman, Brandon
Because the properties of the films are significantly affected by a deposition temperature change of only several degrees Celsius, it is vital that the substrate temperature be uniform across the entire substrate and constant throughout the deposition process, even while it is being radiatively heated by the evaporant metal. A temperature control substrate stage is being developed at Houghton University for thin metal films produced on 10 cm Si substrates via physical vapor deposition, with a base pressure of 10-6 Torr. To test possible substrate-stage adhesion materials, a test chamber was set up containing a substrate fixed to a 10 cm diameter aluminum heat sink. Resistive wire was epoxied to the substrate surface to simulate the ~6.5 W of radiative heating that would occur during deposition. Using double-sided copper tape, the minimum temperature change was 18°C in 10 minutes. Adding clamps decreased this to 13°C in 10 minutes. Using Ag paste as an adhesive resulted in a temperature change of only 3°C in 10 minutes.
XLI Annual Rochester Symposium for Physics Students, University of Rochester (Rochester, NY), April 15, 2023.
A Temperature Control Stage for the Deposition of Thin Metal Films
(Houghton University, 2024-04-20) Fall, Owen; Yelle, Luke; Hoffman, Brandon
A thermal substrate stage was developed for physical vapor deposition of thin metal films. The stage can maintain a uniform, constant temperature across a 4 cm diameter substrate throughout the deposition process, even while it is being radiatively heated at ~5 W for 10 min by the evaporate metal. The substrate is adhered to an 11 cm diameter, 6.4 cm long aluminum heat sink. Previous experiments concluded that Ag paste produced the best thermal contact between the substrate and heat sink. To balance the most surface area possible for thermal contact and removability of the paste, grooves were made in the heat sink. The control stage features ceramic standoffs, holding the aluminum heat sink to the inside of the deposition chamber, and a heater wire pasted to the heat sink to initialize and stabilize the desired temperature.
XLII Annual Rochester Symposium for Physics Students, University of Rochester, April 20, 2024
A Test of the Validity of Inviscid Wall-Modeled LES
(Houghton College, 2015-11-22) Redman, Andrew; Craft, Kyle; Aikens, Kurt
Computational expense is one of the main deterrents to more widespread use of large eddy simulations (LES). As such, it is important to reduce computational costs whenever possible. In this vein, it may be reasonable to assume that high Reynolds numbers flows with turbulent boundary layers and inviscid when using a wall model. This assumption relies on the grid being too coarse to resolve either the viscous length scales in the outer flow or those near near walls. We are not aware of other studies that have suggested or examined the validity of this approach. The inviscid wall-modeled LES assumption is tested here for supersonic flow over a flat plate on three differennt grids. Inviscid and viscous results are compared to those of another wall-modelled LES as well as experimental data-the results appear promising. Furthermore, the inviscid assumption reduces simulation costs by about 25% and 39% for supersonic and subsonic flows, respectively, with the current LES aapplication. Reccommendations are presented as are future areas of research.
68th Annual Meeting of the APS Division of Fluid Dynamics, Boston, MA, Nov. 22-24, 2015; XXXV Annual Rochester Symposium for Physics Students, University of Rochester, Rochester, NY., April 2, 2016.
A TNSA Technique to Measure Light-Ion Cross Sections Using the MTW Laser
(Houghton University, 2023-11-03) Lei, Chunsun; Harley, Noah; Hotchkiss, Andrew; Martin, Andrew; Yuly, Mark; Padalino, Stephen J.; Forrest, Chad J.; Sangster, Thomas C.; Regan, Sean P.
An experiment was performed using the Multi-Terawatt Laser (MTW) at the Laboratory for Laser Energetics (LLE) to test the feasibility of using Target Normal Sheath Acceleration (TNSA) to measure 0.1 - 10 MeV light-ion cross sections. Laser pulses (∼22 J, 7 ps) struck a 0.25 mm2 deuterated polyethylene (CD2) target, ejecting TNSA deuterons that hit a thin natural Li target film on a 25 μm thick stainless-steel substrate, causing the 7Li(d,p)8Li reaction. The phoswich scintillator, light guide, and photomultiplier tube of the Short-Lived Isotope Counting System (SLICS) were placed immediately behind the Li target, and a CAEN Digitizer was used to count the 840 ms half-life beta decay of 8Li, beginning a few milliseconds after the laser shot. The phoswich detector consisted of a fast thin and slow thick scintillator sandwiched together to allow incident particles to be identified by their different rates of energy loss. Incident deuteron energy spectra were measured using time-of-flight (TOF) to a small scintillator in front of the Li target and, for comparison, with a Thompson parabola spectrometer. Funded in part by a grant from the DOE through the Laboratory for Laser Energetics, and by SUNY Geneseo and Houghton University.
65th Annual Meeting of the APS Division of Plasma Physics, Denver, CO, October 30 – November 3, 2023.
An Ambient Air Scanning Tunneling Microscope to Study the Surfaces of Thin Metal Films
(Houghton College, 2022-04-08) Wilson, Joshua C.; Hoffman, Brandon
XL Annual Rochester Symposium for Physics Students, University of Rochester, April 8, 2022.
An Experiment Simulating the Production, Capture, and Detection of 8Li from an ICF Implosion
(Houghton University, 2023-04-15) Lei, Chunsun; Hotchkiss, Andrew; Brown, Adam E.; Martin, Andrew L.; Yuly, Mark; McLean, James G.; Padalino, Stephen J.; Forrest, Chad J.; Sangster, Thomas C.; Regan, Sean P.
Inertial confinement fusion (ICF) is a possible tool for measuring light-ion nuclear cross sections. One way to do this might be to trap and detect the radioactive decays of the product nuclei produced using a doped target capsule. Some of the highest yield light-ion reactions that could be studied using this technique are 6Li(t,p) 8Li and 9Be(t,α) 8Li, both of which produce 8Li . In order to simulate this method, a natural lithium film was deposited onto a tungsten substrate, which was then activated via the 7Li(d,p) 8Li reaction using the SUNY Geneseo Pelletron accelerator. A current pulse of up to 1000 A was discharged through the tungsten raising its temperature to as high as about 1500 °C in less than a few milliseconds, causing the lithium to rapidly evaporate and produce a gas of neutral lithium atoms which then travelled outward and stuck to the aluminum getter detector foil of the Short-Lived Isotope Counting System (SLICS). This phoswich detector was used to identify beta particles and count in situ the 840 ms beta decay curve for 8Li as a function of time in order to estimate the efficiency of SLICS for trapping and detecting ICF reaction products. Funded in part by a grant from the DOE through the Laboratory for Laser Energetics, and by SUNY Geneseo and Houghton University.
XLI Annual Rochester Symposium for Physics Students, University of Rochester (Rochester, NY), April 15, 2023.
An Experiment to Simulate Trapping and Detection of Radioactive Isotopes Produced in ICF Implosions
(Houghton College, 2022-04-27) Christensen, Micah J.; Condie, Micah K.; Brown, Adam E.; Yuly, Mark; McLean, James G.; Padalino, Stephen J.; Forrest, Chad J.; Sangster, Thomas C.; Regan, Sean
It may be possible to measure the low energy nuclear cross sections of light ion reactions by trapping the reaction products from an Inertial Confinement Fusion (ICF) implosion and detecting their beta decays. To test this idea, an “exploding wire” experiment was designed to simulate the expanding gas released in an ICF event. A copper plated tungsten foil was inserted into a vacuum chamber and activated with a deuteron beam via 65 Cu(d, p) 66 Cu. A current pulse through the tungsten then vaporized the copper to create an expanding radioactive gas, simulating the gas behavior in the ICF target chamber following the laser shot. Attempts were made to capture some gas and detect the 66 Cu beta decays using two trap designs, one using a getter and the other a turbopump. Both designs used the Short Lived Isotope Counting System (SLICS), consisting of plastic scintillator phoswich detectors and fast electronics, to identify and count the beta particles. Funded in part by a grant from the DOE through the Laboratory for Laser Energetics, and by SUNY Geneseo and Houghton College.
OMEGA Laser User’s Group Meeting, Laboratory for Laser Energetics, Rochester, NY, April 27, 2022; 63rd Annual Meeting of the APS Division of Plasma Physics, Pittsburgh, PA, November 8-12, 2021; XL Annual Rochester Symposium for Physics Students, University of Rochester, April 8, 2022; 2022 Omega Laser Facility Users Group Workshop Student Poster Award
Analysis of a Measurement of 12C(n,2n)11C Cross Sections
(Houghton College, 2013-11-11) Hartshaw, Garrett; Love, Ian; Yuly, Mark; Padalino, Stephen; Russ, Megan; Bienstock, Mollie; Simone, Angela; Ellison, Drew; Desmitt, Holly; Massey, Thomas; Sangster, Craig
In inertial confinement fusion (ICF), nuclear fusion reactions are initiated by bombarding a small fuel pellet with high power lasers. One ICF diagnostic tool involves placing graphite discs within the reaction chamber to determine the number of high-energy neutrons. This diagnostic requires accurate 12C(n,2n)11C cross sections, which have not been previously well measured. An experiment to measure this cross section was conducted at Ohio University, in which DT neutrons irradiated polyethylene and graphite targets. The neutron flux was determined by counting recoil protons from the polyethylene in a silicon dE-E detector telescope. Preliminary cross sections were calculated using the incident neutron flux and the number of 11C nuclei in the graphite and polyethylene targets determined by counting, in a separate counting station, the gamma rays resulting from the positron decay of 11C. This poster will present the data analysis techniques used to determine theses cross sections and the calculation of the corrections needed to account for the detector and target geometry. Funded in part by a LLE contract through the DOE.
55th Annual Meeting of the APS Division of Plasma Physics, Denver, Colorado, November 11-15, 2013; Omega Laser Facility Users Group Workshop, Laboratory for Laser Energetics, Rochester, NY, April 23-25, 2014.
Background Rates Outside the OMEGA-60 Target Chamber Seconds to Minutes After a High-Yield Shot
(Houghton College, 2022-04-27) Raymond, Steven; Kowalewski, Tyler; Yuly, Mark; Padalino, Stephen; Forrest, Chad J.; Sangster, Craig; Regan, Sean
Inertial confinement fusion may be used to make fundamental nuclear science measurements of low-energy light-ion cross sections also of interest in astrophysics and fusion research. The feasibility of collecting and counting the beta decay of the reaction products (half-life 20 ms to 20 s) in the expanding neutral gas after the ICF shot is being studied using two types of “traps” – a getter and a turbopump. Both of these use phoswich detectors to identify beta particles and count the beta decays of the trapped product nuclei. One concern with this technique is that the background rate, even relatively long after the shot, may still be too high relative to the small number of detected product nuclei. An OMEGA ride-along experiment was performed to measure the background rates in these detectors from milliseconds to seconds after the laser shot. Funded in part by a grant from the DOE through the Laboratory for Laser Energetics, and by SUNY Geneseo and Houghton College.
OMEGA Laser User’s Group Meeting, Laboratory for Laser Energetics, Rochester, NY, April 27, 2022;
63rd Annual Meeting of the APS Division of Plasma Physics, Pittsburgh, PA, November 8-12, 2021.

The Houghton College Cyclotron consists of a 17 cm inner diameter evacuated aluminum chamber containing a “dee” shaped electrode and a grounded “dummy dee” placed between the poles of a 1.2 T electromagnet. Low pressure gas is introduced into the chamber where a filament, through electron collisions, ionizes the gas. The ions are accelerated in a spiral path by an alternating RF electric field in the constant magnetic field. It is expected that the accelerated ions will reach maximum energies of 400 keV, 200 keV, and 100 keV for protons, deuterons, and helium respectively. The cyclotron has successfully accelerated protons and helium ions. Currently, the performance of the cyclotron is being optimized for future small-scale nuclear experiments.

A system for creating Sn or Ag coated Li targets was developed for a Multi-Terra Watt (MTW) laser Target Normal Sheath Acceleration (TNSA) experiment to study the 7Li(d, p)8Li reaction. The Li targets were designed to have a ~50 nm thick coating to prevent Li from interacting with air and water vapor and be ~2 μm thick to reduce energy loss. The films were produced in a ~10−5 Torr evacuated deposition chamber in which about 15 A flowing one way through a diode circuit heated a stainless-steel boat holding a Li pellet to a thermocouple-measured temperature of nearly 400℃, evaporating the Li onto a 25 μm thick stainless-steel substrate. A current of up to 60 amps flowing the opposite direction through another diode heated a molybdenum boat holding a Sn or Ag pellet, evaporating the metal and forming the thin coating over the Li. The thicknesses were measured using a micrometer, magnetic adhesion, a home-made mechanical profilometer, and Rutherford backscattering. To allow Li metal to be weighed and inserted into the boat, an Air-filled glove box was constructed around the deposition chamber. Funded in part by a grant from the DOE through the Laboratory for Laser Energetics, and by SUNY Geneseo and Houghton University.

An attempt to measure the 12C(n,2n)11C cross section for high energy neutrons in the range of 20-30 MeV was conducted using Ohio University’s accelerator facility as a fast neutron source. The neutrons were incident on a graphite target and the β+ decay of the activated carbon-11 nuclei were observed in an on-axis gamma ray detector pair. To predetermine the efficiency of this gamma ray detector system, a boron-11 activation experiment was performed. Using SUNY Geneseo’s 1.7 MV tandem pelletron accelerator, 3.1 MeV protons were incident upon the 11B foil inducing the 11B(p,n)11C reaction to occur at a high rate of activation. The 11C decays via ?+ emission, then upon annihilation with an electron creates characteristic 511-511 keV photon pairs which were counted using coincidence methods. Since the 11B(p,n) cross section is well defined, a calculation was performed to determine the expected number of activations and later compared to the total number of decays observed in the counting system. Funded in part by a grant from the DOE through the Laboratory for Laser Energetics.

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