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Search Results: 1 - 10 of 276179 matches for " E. V. Hungerford "
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A. Fluka Study of Underground Cosmogenic Neutron Production
A Empl,E. V. Hungerford,R. Jasim,P. Mosteiro
Physics , 2014, DOI: 10.1088/1475-7516/2014/08/064
Abstract: Neutrons produced by cosmic muon interactions are important contributors to backgrounds in underground detectors when searching for rare events. Typically such neutrons can dominate the background, as they are particularly difficult to shield and detect. Since actual data is sparse and not well documented, simulation studies must be used to design shields and predict background rates. Thus validation of any simulation code is necessary to assure reliable results. This work compares in detail the predictions of the FLUKA simulation code to existing data, and uses this code to report a simulation of cosmogenic backgrounds for typical detectors embedded in a water tank with liquid scintillator shielding.
A FLUKA Study of $β$-delayed Neutron Emission for the Ton-size DarkSide Dark Matter Detector
Anton Empl,Ed V. Hungerford
Physics , 2014,
Abstract: In the published cosmogenic background study for a ton-sized DarkSide dark matter search, only prompt neutron backgrounds coincident with cosmogenic muons or muon induced showers were considered, although observation of the initiating particle(s) was not required. The present paper now reports an initial investigation of the magnitude of cosmogenic background from $\beta$-delayed neutron emission produced by cosmogenic activity in DarkSide. The study finds a background rate for $\beta$-delayed neutrons in the fiducial volume of the detector on the order of < 0.1 event/year. However, detailed studies are required to obtain more precise estimates. The result should be compared to a radiogenic background event rate from the PMTs inside the DarkSide liquid scintillator veto of 0.2 events/year.
Higher Twist Effects in Parton Fragmentation Functions
Guanghua Xu,Ed V. Hungerford,Larry Pinsky
Physics , 2005,
Abstract: We study twist expansions for parton fragmentation functions based on the definition of the twist as an invariant matrix element of a light-cone, bilocal operator. The results are then applied to a method which might be used to extract higher twist effects in the fragmentation sector using both $e^+ e^-$, and $e^- p$ collisions. We discuss how to apply the later measurements to experiments at the Jefferson National Acceleration Facility.
Study of Cosmogenic Neutron Backgrounds at LNGS
A. Empl,R. Jasim,E. Hungerford,P. Mosteiro
Physics , 2012,
Abstract: Cosmic muon interactions are important contributors to backgrounds in underground detectors when searching for rare events. Typically neutrons dominate this background as they are particularly difficult to shield and detect in a veto system. Since actual background data is sparse and not well documented, simulation studies must be used to design shields and predict background rates. This means that validation of any simulation code is necessary to assure reliable results. This work studies the validation of the FLUKA simulation code, and reports the results of a simulation of cosmogenic background for a liquid argon two-phase detector embedded within a water tank and liquid scintillator shielding.
Solar neutrino detection in a large volume double-phase liquid argon experiment
D. Franco,C. Giganti,P. Agnes,L. Agostino,B. Bottino,S. Davini,S. De Cecco,A. Fan,G. Fiorillo,C. Galbiati,A. M. Goretti,E. V. Hungerford,Al. Ianni,An. Ianni,C. Jollet,L. Marini,C. J. Martoff,A. Meregaglia,L. Pagani,M. Pallavicini,E. Pantic,A. Pocar,A. L. Renshaw,B. Rossi,N. Rossi,Y. Suvorov,G. Testera,A. Tonazzo,H. Wang,S. Zavatarelli
Physics , 2015,
Abstract: The direct search for dark matter WIMP particles through their interaction with nuclei at the "neutrino floor" sensitivity, where neutrino-induced coherent scattering on nuclei starts contributing to the background, requires detectors capable of collecting exposures of the order of 1~ktonne yr free of background resulting from beta and gamma decays and cosmogenic and radiogenic neutrons. The same constraints are required for precision measurements of solar neutrinos elastically scattering on electrons. Two-phase liquid argon time projection chambers (LAr TPCs) are prime candidates for the ambitious program to explore the nature of dark matter. The large target, high scintillation light yield and good spatial resolution in all three cartesian directions concurrently allows a high precision measurement of solar neutrino fluxes. We studied the cosmogenic and radiogenic backgrounds affecting solar neutrino detection in a 300 tonne (100 tonne fiducial) LAr TPC operating at LNGS depth (3,800 meters of water equivalent). Such a detector could measure the CNO neutrino rate with 5 sigma sensitivity, and significantly improve the precision of the 7Be and pep neutrino rates compared to the currently available results from the Borexino organic liquid scintillator detector. Measurements with ~2%, ~10% and ~15% precision for 7Be, pep, and CNO neutrinos, respectively, are possible.
Choroidal Metastasis from Follicular Cell Thyroid Carcinoma Masquerading as Circumscribed Choroidal Haemangioma
V. P. Papastefanou,A. K. Arora,J. L. Hungerford,V. M. L. Cohen
Case Reports in Oncological Medicine , 2014, DOI: 10.1155/2014/251817
Abstract: Choroidal metastases from follicular thyroid carcinoma are uncommon and usually present as an amelanotic lesion against a background of known systemic disease. We present the case of a 56-year-old woman with a thyroid metastatic focus with unusual clinical presentation, systemic involvement, and early response to systemic treatment. A review of the literature accompanies this case presentation. 1. Case Presentation A 56-year-old lady was referred to the Ocular Oncology Service with a seven-year history of deteriorating visual acuity in the left eye. Patient had a 15-year history of sarcoidosis associated with recurrent uveitis. Best-corrected visual acuity was at 6/36?OS 6/6?OD. At presentation there was no active uveitis. Posterior segment examination revealed an elevated lesion inferotemporally to the macula of the left eye measuring 6.5 × 6.8?mm that was pale orange in colour and difficult to discern clinically from the surrounding retina (Figure 1(a)). A fundus fluorescein angiogram indicated early hyperfluorescence. B-scan ultrasound demonstrated a dome-shaped lesion with high internal reflectivity measuring 2.7?mm in elevation. A Doppler B-scan ultrasound indicated the presence of internal blood flow. Clinical appearance at presentation was typical of a circumscribed choroidal haemangioma although a metastatic deposit remained within the differential diagnosis. No ocular treatment was performed but review was arranged in 3 months pending ongoing investigations for a thyroid gland mass discovered on a routine CT scan of the neck and chest. Figure 1: (a) Pale orange lesion involving the macula and extending inferotemporally before treatment. Clinical appearance is consistent with a circumscribed choroidal haemangioma. (b) After four months a pale, fibrotic scar has developed in the site of the original lesion following treatment. Thyroid gland biopsy proved the mass was a follicular cell carcinoma of the thyroid and systemic staging revealed stage 4 disease due to the presence of bone metastases in the left iliac crest and in the right femur, the latter causing a pathologic fracture. Patient underwent total thyroidectomy. Excision was incomplete and patient received 2 initial sessions of adjuvant treatment of radioactive iodine (131I) therapy (4.9 and 5.8?GBq, resp.). The pathologic fracture was managed with internal fixation and adjuvant external beam radiotherapy (EBRT) with 35?Gy at 15 sessions in the iliac crest and 20?Gy in the femur. Following radioactive treatment of the thyroid gland the visual acuity reduced to counting fingers. Fundus
New Limit for the Family-Number Non-conserving Decay mu+ to e+_gamma
MEGA Collaboration,M. L. Brooks,Y. K. Chen,M. D. Cooper,P. S. Cooper,M. Dzemidzic,A. Empl,C. A. Gagliardi,G. E. Hogan,E. B. Hughes,E. V. Hungerford,C. C. H. Jui,J. E. Knott,D. D. Koetke,M. A. Kroupa K. A. Lan,R. Manweiler,B. W. Mayes,R. E. Mischke,L. E. Piilonen,T. D. S. Stanislaus,K. M. Stantz,J. J. Szymanski,R. E. Tribble,X. L. Tu,L. A. Van Ausdeln,W. H. von Witsch,S. C. Wright,K. O. H. Ziock
Physics , 1999, DOI: 10.1103/PhysRevLett.83.1521
Abstract: An experiment has been performed to search for the muon- and electron-number non-conserving decay mu+ to e+_gamma. The upper limit for the branching ratio to be GAMMA(mu+ to e+_gamma)/GAMMA(mu+ to e+_nu_nubar) < 1.2e-11 with 90% confidence.
Snowmass CF1 Summary: WIMP Dark Matter Direct Detection
P. Cushman,C. Galbiati,D. N. McKinsey,H. Robertson,T. M. P. Tait,D. Bauer,A. Borgland,B. Cabrera,F. Calaprice,J. Cooley,T. Empl,R. Essig,E. Figueroa-Feliciano,R. Gaitskell,S. Golwala,J. Hall,R. Hill,A. Hime,E. Hoppe,L. Hsu,E. Hungerford,R. Jacobsen,M. Kelsey,R. F. Lang,W. H. Lippincott,B. Loer,S. Luitz,V. Mandic,J. Mardon,J. Maricic,R. Maruyama,R. Mahapatra,H. Nelson,J. Orrell,K. Palladino,E. Pantic,R. Partridge,A. Ryd,T. Saab,B. Sadoulet,R. Schnee,W. Shepherd,A. Sonnenschein,P. Sorensen,M. Szydagis,T. Volansky,M. Witherell,D. Wright,K. Zurek
Physics , 2013,
Abstract: As part of the Snowmass process, the Cosmic Frontier WIMP Direct Detection subgroup (CF1) has drawn on input from the Cosmic Frontier and the broader Particle Physics community to produce this document. The charge to CF1 was (a) to summarize the current status and projected sensitivity of WIMP direct detection experiments worldwide, (b) motivate WIMP dark matter searches over a broad parameter space by examining a spectrum of WIMP models, (c) establish a community consensus on the type of experimental program required to explore that parameter space, and (d) identify the common infrastructure required to practically meet those goals.
The Life-History of Mesovelia Mulsanti White
H. B. Hungerford
Psyche , 1917, DOI: 10.1155/1917/57095
Some Notonecta From South America
H. B. Hungerford
Psyche , 1926, DOI: 10.1155/1926/90626
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