Session B17: Undergraduate Research I

On Demand

A capacitive distance sensor is being developed for measuring the position of a levitating half-wave plate, with a target resolution of .1mm. In addition to designing the sensor PCB, software is written for calibration, distance conversion, and real-time visualization. There are two main challenges to accurate distance conversion. First of all, many uncontrollable conditions that can change the amount of “ground” in the surroundings of the sensor, such as whether a person is nearby, may be serious sources of interference. An environmental reading can be used to subtract out the interference to a large extent, but the effect can also be reduced by means like active shielding. Secondly, capacitance depends on the particular geometry. However, it is hard to directly test and calibrate inside the actual instrument or create an authentic replica for testing. Therefore, a combined approach can be taken for calibration, such that a mock setup is used to extract those parameters which are easier to replicate, while others are calibrated using some simple procedure in situ.   

On Demand

The Society of Physics Students at Kennesaw State University are working on designing portable cosmic ray muon detectors. The detectors consist of a series of small parallel-plate capacitors which operate at low voltage to detect ionization currents in ambient air, in order to be robust enough for a variety of outdoor muography applications. The detectors have been tested in the laboratory and are able to observe the direct ionization currents from 0.9 microcurie alpha and beta sources without any additional amplification. The addition of amplification and noise reduction to the detector electronics will enable the detector to increase its sensitivity to be able to observe cosmic ray muons. To amplify the signal, the operational amplifier AD8099 is being used. The benefits of this op-amp are it operates at high frequencies that allow the clearest signal for detection, in addition to having a high gain. When the signal can be separated from the electronic background noise, then the circuit can be modified by narrowing the bandwidth to the signal frequency. This talk will focus on the design and performance of the detector electronics and amplification.   

Search for Higgsino inside Large Hadron Collider via Vector Boson Fusion

Supersymmetry (SUSY) is a theoretical extension of the standard model (SM) of particle physics that could describe the particle nature of Dark Matter (DM). In SUSY models assuming R-parity conservation, the lightest neutralino is neutral, stable, and interacts with SM particles in the early universe to give the DM relic density observed today. A Higgs-like neutralino (Higgsino) is known to be a promising candidate for DM. Current search methods for Higgsinos at the LHC mainly rely on Drell-Yan production mechanisms, however, are experimentally difficult in cases where the mass of the DM candidate is only slightly less than the masses of other neutralinos, making these so-called compressed spectrum Higgsino scenarios important search targets using new techniques. The focus of this talk is on the development of a search methodology for Higgsino DM at LHC using Vector Boson Fusion (VBF) processes, which offers an alternative and complementary search strategy. We combine the VBF topology with a final state of one and two soft leptons and large missing momentum. The requirement of one or two soft leptons combined with jets of large dijet mass can significantly reduce SM backgrounds, resulting in enhanced Higgsino discovery potential at the LHC.   

Ultralight Dark Matter in the Solar System: Numerical Approaches

Dark matter is known to be gravitationally bound to the Milky Way galaxy and thus passes through our Solar System. Attempts to detect dark matter passing through the solar system are already underway with projects like ADMX. If dark matter were trapped in the protosolar nebula of the sun, then a significant density could be present at Earth today, if the dark matter was not expelled from the solar system by gravitational perturbations due to Jupiter or other planets. In order to investigate the longevity of dark matter in Solar orbits we combined analytic results (where possible) with numerical simulations. The effects of Jupiter were studied by numerically integrating the equations of motion for dark matter particles. Since direct detection of dark matter requires Earth-crossing orbits, we also considered the gravitational effects of close encounters with Earth. The effects of repeated close encounters were treated statistically. We conclude that, in the absence of non-gravitational interactions, a significant fraction of an initial dark matter population could remain today   

Synthesis of fluorescent gold nanoparticle and their application in the photothermal treatment of HCC 1395 cell lines

Monodispersed, fluorescent gold nanoparticles with~gallic~acid based ligand shells are synthesized at~various~concentrations with an average particle size of~1-2nm.~Monodispersity and particle~size are confirmed via dynamic light scattering. The Surface Plasmon Resonance (SPR) peak is determined via UV-Vis. Afterwards~HCC 1395~cells, derived from breast cancer cells,~are infused with the gold nanoparticles. Results are presented on how~infusion with~gold nanoparticles and~photothermal~treatment affect the cell viability. The~photothermal~treatment of the solution is performed at 532nm with a~MGL~III 532-300mW~laser near the SPR peak over different time intervals.~The photothermal~treatment of the solution results in a locally raised temperature and can possibly affect cell viability. After photothermal treatment and incubation for 24hours,~the cells are stained and cell viability is analyzed.