Search for solar axions LAZARUS, D. M; SMITH, G. C; CAMERON, R ...
Physical review letters,
10/1992, Letnik:
69, Številka:
16
Journal Article
Recenzirano
We have searched for a flux of axions produced in the sun by exploiting their conversion to X-rays in a static magnetic field. The signature of a solar axion flux would be an increase in the rate of ...X-rays detected in a magnetic telescope when the sun passes within its acceptance. From the absence of such a signal we set a 3 sigma limit on the axion coupling to two photons. (Author)
Progenitor scenarios for short gamma-ray bursts (short GRBs) include coalescenses of two neutron stars or a neutron star and black hole, which would necessarily be accompanied by the emission of ...strong gravitational waves. We present a search for these known gravitational-wave signatures in temporal and directional coincidence with 22 GRBs that had sufficient gravitational-wave data available in multiple instruments during LIGO's fifth science run, S5, and Virgo's first science run, VSR1. We find no statistically significant gravitational-wave candidates within a -5, +1) s window around the trigger time of any GRB. Using the Wilcoxon-Mann-Whitney U test, we find no evidence for an excess of weak gravitational-wave signals in our sample of GRBs. We exclude neutron star-black hole progenitors to a median 90% CL exclusion distance of 6.7 Mpc.
We present the results of a search for gravitational-wave bursts associated with 137 gamma-ray bursts (GRBs) that were detected by satellite-based gamma-ray experiments during the fifth LIGO science ...run and first Virgo science run. The data used in this analysis were collected from 2005 November 4 to 2007 October 1, and most of the GRB triggers were from the Swift satellite. The search uses a coherent network analysis method that takes into account the different locations and orientations of the interferometers at the three LIGO-Virgo sites. We find no evidence for gravitational-wave burst signals associated with this sample of GRBs. Using simulated short-duration (<1 s) waveforms, we set upper limits on the amplitude of gravitational waves associated with each GRB. We also place lower bounds on the distance to each GRB under the assumption of a fixed energy emission in gravitational waves, with typical limits of D ~ 15 Mpc (E_GW^iso / 0.01 M_o c^2)^1/2 for emission at frequencies around 150 Hz, where the LIGO-Virgo detector network has best sensitivity. We present astrophysical interpretations and implications of these results, and prospects for corresponding searches during future LIGO-Virgo runs.
A personal recount in areas of particle physics and related fields as a research physicist for over 50 years, Adrian Melissinos' insights into the ways that general research was carried out, as well ...as the evolution of particle physics from 1958 to 2008 will prove valuable to science history enthusiasts, as well as particle physicists.Be it conventional accelerator experiments, the use of microwave techniques in search of cosmic axions, or taking advantage of high power lasers to observe light-by-light scattering, the excitement of searching for something new in the face of failures and then successes is enriching, and the collaboration with gifted and outstanding colleagues and students proves insightful.A hybrid of personal reminiscences and a professional journey, readers get to relive the joy and excitement of researching and teaching in small groups during those early years while gaining a partial historical perspective of particle physics since 1958 - all in Reminiscences: A Journey through Particle Physics. /remove
Laser system for a high duty cycle photoinjector Fry, A.R.; Fitch, M.J.; Melissinos, A.C. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
07/1999, Letnik:
430, Številka:
2
Journal Article
Recenzirano
Odprti dostop
We have developed a solid-state laser system that produces a 1 MHz pulse train of 800 equal amplitude pulses with 25 μJ per pulse at
λ=1054
nm
; the repetition rate is 1 Hz. The laser pulse train is ...produced by a mode-locked Nd:YLF oscillator, synchronized to the phase of the photoinjector RF. The pulses are amplified in a Nd
:
glass multipass amplifier followed by a two-pass amplifier. The laser system uses chirped pulse amplification to produce 2 ps pulses. After two stages of second harmonic generation to
λ=263
nm
and transport losses,
5
μJ
per pulse of UV are available at the Cs
2Te photocathode of the RF gun. The photocathode quantum efficiency is in the 2–6% range, and electron bunches with charge in excess of 10 nC have been extracted during photoinjector operation.
Background: The current treatment of displaced intraarticular calcaneal fractures has been surgical fixation. The objective of this study was to evaluate the use of indirect reduction with Ilizarov ...external fixation as a viable alternative in the surgical treatment of certain calcaneal fractures. Methods: Thirty-one patients with 33 fractures of the calcaneus (Sanders types II, III, and IV) were treated using small wire circular external fixation. A limited percutaneous plantar skin incision was used to improve reduction of the posterior facet. Fractures were evaluated by preoperative CT scans and classified by an independent observer. Patients were evaluated by physical examination as well as by the AOFAS hindfoot score questionnaire. Followup ranged from 6 months to 4 years. Results: The average AOFAS score for 18 patients available for examination was 66 (42 to 92). The average score increased to 74 for patients with more than 10 months followup and to 77 for patients with isolated calcaneal fractures. Open fractures also had early debridement and soft-tissue coverage; no deep infections were seen in this subgroup. There were 11 complications, including nine superficial pin track infections, one superficial skin necrosis under an area of fracture blister, and one deep infection in a diabetic smoker with severe hemorrhagic fracture blisters. All superficial infections responded to local pin or wound care and oral antibiotics. No secondary reconstructive procedures, including osteotomies, subtalar fusions, or amputations, have been done. All open fractures healed and maintained soft-tissue coverage. Conclusions: Indirect reduction and external fixation is a viable surgical alternative for intraarticular calcaneal fractures. Particularly favorable results were obtained in open fractures when soft-tissue reconstruction also was done. Advantages include shorter time to surgery, immediate weightbearing, minimal invasiveness, few serious wound problems, and no residual hardware. Disadvantages include technical difficulty, incomplete reduction of fracture fragments, and the need for secondary surgery (fixator removal).
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