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1.
Rev Sci Instrum ; 94(4)2023 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38081262

RESUMO

We describe the first implementation of a Josephson Traveling Wave Parametric Amplifier (JTWPA) in an axion dark matter search. The operation of the JTWPA for a period of about two weeks achieved sensitivity to axion-like particle dark matter with axion-photon couplings above 10-13 Ge V-1 over a narrow range of axion masses centered around 19.84 µeV by tuning the resonant frequency of the cavity over the frequency range of 4796.7-4799.5 MHz. The JTWPA was operated in the insert of the axion dark matter experiment as part of an independent receiver chain that was attached to a 0.56-l cavity. The ability of the JTWPA to deliver high gain over a wide (3 GHz) bandwidth has engendered interest from those aiming to perform broadband axion searches, a longstanding goal in this field.

2.
Phys Rev Lett ; 131(10): 101002, 2023 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-37739367

RESUMO

We report the first result of a direct search for a cosmic axion background (CaB)-a relativistic background of axions that is not dark matter-performed with the axion haloscope, the Axion Dark Matter eXperiment (ADMX). Conventional haloscope analyses search for a signal with a narrow bandwidth, as predicted for dark matter, whereas the CaB will be broad. We introduce a novel analysis strategy, which searches for a CaB induced daily modulation in the power measured by the haloscope. Using this, we repurpose data collected to search for dark matter to set a limit on the axion photon coupling of a CaB originating from dark matter cascade decay via a mediator in the 800-995 MHz frequency range. We find that the present sensitivity is limited by fluctuations in the cavity readout as the instrument scans across dark matter masses. Nevertheless, we suggest that these challenges can be surmounted using superconducting qubits as single photon counters, and allow ADMX to operate as a telescope searching for axions emerging from the decay of dark matter. The daily modulation analysis technique we introduce can be deployed for various broadband rf signals, such as other forms of a CaB or even high-frequency gravitational waves.

3.
Rev Sci Instrum ; 92(12): 124502, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34972408

RESUMO

Axion dark matter experiment ultra-low noise haloscope technology has enabled the successful completion of two science runs (1A and 1B) that looked for dark matter axions in the 2.66-3.1 µeV mass range with Dine-Fischler-Srednicki-Zhitnisky sensitivity [Du et al., Phys. Rev. Lett. 120, 151301 (2018) and Braine et al., Phys. Rev. Lett. 124, 101303 (2020)]. Therefore, it is the most sensitive axion search experiment to date in this mass range. We discuss the technological advances made in the last several years to achieve this sensitivity, which includes the implementation of components, such as the state-of-the-art quantum-noise-limited amplifiers and a dilution refrigerator. Furthermore, we demonstrate the use of a frequency tunable microstrip superconducting quantum interference device amplifier in run 1A, and a Josephson parametric amplifier in run 1B, along with novel analysis tools that characterize the system noise temperature.

4.
Phys Rev Lett ; 127(26): 261803, 2021 Dec 24.
Artigo em Inglês | MEDLINE | ID: mdl-35029490

RESUMO

We report the results from a haloscope search for axion dark matter in the 3.3-4.2 µeV mass range. This search excludes the axion-photon coupling predicted by one of the benchmark models of "invisible" axion dark matter, the Kim-Shifman-Vainshtein-Zakharov model. This sensitivity is achieved using a large-volume cavity, a superconducting magnet, an ultra low noise Josephson parametric amplifier, and sub-Kelvin temperatures. The validity of our detection procedure is ensured by injecting and detecting blind synthetic axion signals.

5.
Phys Rev Lett ; 124(10): 101303, 2020 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-32216421

RESUMO

This Letter reports on a cavity haloscope search for dark matter axions in the Galactic halo in the mass range 2.81-3.31 µeV. This search utilizes the combination of a low-noise Josephson parametric amplifier and a large-cavity haloscope to achieve unprecedented sensitivity across this mass range. This search excludes the full range of axion-photon coupling values predicted in benchmark models of the invisible axion that solve the strong CP problem of quantum chromodynamics.

6.
Phys Rev Lett ; 120(15): 151301, 2018 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-29756850

RESUMO

This Letter reports the results from a haloscope search for dark matter axions with masses between 2.66 and 2.81 µeV. The search excludes the range of axion-photon couplings predicted by plausible models of the invisible axion. This unprecedented sensitivity is achieved by operating a large-volume haloscope at subkelvin temperatures, thereby reducing thermal noise as well as the excess noise from the ultralow-noise superconducting quantum interference device amplifier used for the signal power readout. Ongoing searches will provide nearly definitive tests of the invisible axion model over a wide range of axion masses.

7.
Phys Rev Lett ; 121(26): 261302, 2018 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-30636160

RESUMO

The µeV axion is a well-motivated extension to the standard model. The Axion Dark Matter eXperiment (ADMX) collaboration seeks to discover this particle by looking for the resonant conversion of dark-matter axions to microwave photons in a strong magnetic field. In this Letter, we report results from a pathfinder experiment, the ADMX "Sidecar," which is designed to pave the way for future, higher mass, searches. This testbed experiment lives inside of and operates in tandem with the main ADMX experiment. The Sidecar experiment excludes masses in three widely spaced frequency ranges (4202-4249, 5086-5799, and 7173-7203 MHz). In addition, Sidecar demonstrates the successful use of a piezoelectric actuator for cavity tuning. Finally, this publication is the first to report data measured using both the TM_{010} and TM_{020} modes.

8.
Dis Esophagus ; 26(1): 91-6, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22394249

RESUMO

The purpose of this study is to apply combined multichannel intraluminal impedance and esophageal manometry (MII-EM) to test esophageal function during solid swallowing in a normal healthy population. We determined whether combined MII-EM with solid bolus is more sensitive than that with viscous bolus in the detection of motility abnormality. Eighteen healthy volunteers (11 men and 7 women; mean age 22 years, range 20-26 years) underwent combined MII-EM with a catheter containing four impedance-measuring segments and five solid-state pressure transducers. Each subject received 10 viscous and 10 solid materials. Tracings were analyzed manually for bolus presence time, total bolus transit time, contraction amplitude, duration, and onset velocity. Three hundred and sixty swallows including viscous and solid materials were analyzed. Contraction amplitude for the viscous swallows was higher at 20 cm above the lower esophageal sphincter (LES) (P= 0.049) but lower at 15 cm above the LES (P < 0.001). Duration of contractions for the solid swallows was longer at 15 cm (P= 0.002) and 10 cm above the LES (P= 0.011) compared with viscous swallows. The total bolus transit time for solid was significantly shorter than that for viscous boluses (6.8 vs. 7.7 seconds, P < 0.001). Bolus presence time appeared to be similar between viscous and solid boluses (except in the proximal esophagus). The percentage of swallows with ineffective peristalsis by manometry, as well as those with incomplete bolus transit by impedance, did not differ between viscous and solid swallows. The proportion of manometrically ineffective solid swallows with incomplete bolus transit was greater than that of viscous swallows (62.1% vs. 34.8%, P= 0.05). Application of solid boluses may potentially enhance diagnostic capability of esophageal function testing. Solid boluses can be regarded as a valuable complement to viscous boluses in the detection of esophageal motility abnormalities when applied with combined MII-EM.


Assuntos
Deglutição/fisiologia , Trânsito Gastrointestinal/fisiologia , Peristaltismo/fisiologia , Adulto , Impedância Elétrica , Feminino , Alimentos , Humanos , Masculino , Manometria/métodos , Valores de Referência , Estudos de Amostragem , Adulto Jovem
9.
Br J Radiol ; 83(988): e83-5, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20335438

RESUMO

CT-guided transthoracic lung biopsy is becoming a widely accepted procedure for the diagnosis of pulmonary lesions. The rate of severe complications following such a procedure has been reported. Of these complications, air embolism is the most likely to be fatal. We report a case of right coronary air embolism resulting in myocardial infarction after a CT-guided percutaneous needle biopsy of the lung. The patient died from underlying malignant disease 4 months later.


Assuntos
Biópsia por Agulha/efeitos adversos , Vasos Coronários , Embolia Aérea/etiologia , Neoplasias Pulmonares/patologia , Pulmão/patologia , Infarto do Miocárdio/etiologia , Adulto , Aorta , Biópsia por Agulha/métodos , Embolia Aérea/diagnóstico por imagem , Evolução Fatal , Humanos , Masculino , Radiografia Intervencionista , Tomografia Computadorizada por Raios X
10.
Phys Rev Lett ; 105(26): 261803, 2010 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-21231645

RESUMO

We report results from a search for chameleon particles created via photon-chameleon oscillations within a magnetic field. This experiment is sensitive to a wide class of unexplored chameleon power-law and dark energy models. These results exclude 5 orders of magnitude in the coupling of chameleons to photons covering a range of 4 orders of magnitude in chameleon effective mass and, for individual models, exclude between 4 and 12 orders of magnitude in chameleon couplings to matter.

11.
Phys Rev Lett ; 102(3): 030402, 2009 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-19257328

RESUMO

We report the first results from the GammeV search for chameleon particles, which may be created via photon-photon interactions within a strong magnetic field. Chameleons are hypothesized scalar fields that could explain the dark energy problem. We implement a novel technique to create and trap the reflective particles within a jar and to detect them later via their afterglow as they slowly convert back into photons. These measurements provide the first experimental constraints on the couplings of chameleons to photons.

12.
Phys Rev Lett ; 100(8): 080402, 2008 Feb 29.
Artigo em Inglês | MEDLINE | ID: mdl-18352604

RESUMO

We report the first results of the GammeV experiment, a search for milli-eV mass particles with axionlike couplings to two photons. The search is performed using a "light shining through a wall" technique where incident photons oscillate into new weakly interacting particles that are able to pass through the wall and subsequently regenerate back into detectable photons. The oscillation baseline of the apparatus is variable, thus allowing probes of different values of particle mass. We find no excess of events above background and are able to constrain the two-photon couplings of possible new scalar (pseudoscalar) particles to be less than 3.1x10;(-7) GeV-1 (3.5x10;(-7) GeV-1) in the limit of massless particles.

13.
Br J Radiol ; 79(947): e187-9, 2006 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-17065285

RESUMO

The coexistence of multiple and synchronous primary neoplasms in the genitourinary system has only rarely been described in the literature. We present the case of a 78-year-old man with haematuria as the initial presentation, finally proven to be transitional cell carcinoma (TCC) combined with renal cell carcinoma (RCC). Intravenous urography (IVU), CT and arterial angiography studies revealed a space-occupying nodule at the right upper renal pelvicalyces showing mild enhancement with contrast medium. Another strong contrast medium enhancing exophytic tumour was found at the lower pole of kidney; there were hypodense foci and calcified components in this lesion. A right nephroureterectomy was performed. Pathological diagnosis was a papillary TCC and a clear cell type RCC. This is a rare case of combined renal malignancies diagnosed by imaging.


Assuntos
Carcinoma de Células Renais/diagnóstico por imagem , Carcinoma de Células de Transição/diagnóstico por imagem , Neoplasias Renais/diagnóstico por imagem , Neoplasias Primárias Múltiplas/diagnóstico por imagem , Idoso , Humanos , Masculino , Tomografia Computadorizada por Raios X
14.
Br J Radiol ; 79(942): 526-8, 2006 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-16714757

RESUMO

Penile lymphoma is extremely rare and secondary involvement of the penis by lymphoma may be due to retrograde spread or to direct extension from neighbouring organ. The appearance of penile lymphoma varies and can be mistaken for other soft tissue tumours. We report on a case with malignant lymphoma of the penis. MRI findings revealed soft-tissue mass of homogeneous isointensity around the middle to distal part of penis on T(1) weighted imaging and T(2) weighted imaging. It was well encapsulated, minimally enhanced and distinct from corpus cavernosum and corpus spongiosum.


Assuntos
Linfoma de Células B/diagnóstico , Neoplasias Penianas/diagnóstico , Idoso , Humanos , Imageamento por Ressonância Magnética , Masculino
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