APL Nameplate
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Flickr Twitter iResearch App Facebook

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Previous Issue Next Issue

19 Mar 2007

Volume 90, Issue 12, Articles (12xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 90, 123101 (2007); http://dx.doi.org/10.1063/1.2716242 (3 pages)

G. Z. Shen, Y. Bando, J. Q. Hu, and D. Golberg
Enlarge Image | Read More
Return to All Sections
back to top
RSS Feeds

Efficiency of composite boron nitride neutron detectors in comparison with helium-3 detectors

J. Uher, S. Pospisil, V. Linhart, and M. Schieber

Appl. Phys. Lett. 90, 124101 (2007); http://dx.doi.org/10.1063/1.2713869 (2 pages) | Cited 6 times

Online Publication Date: 20 March 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
It has been clearly demonstrated that the composite boron nitride (BN) semiconductor polycrystalline bulk detectors with BN grains embedded in a polymer matrix operate as an effective detector of thermal neutrons even if they contain natural boron only. A reasonable signal to noise ratio has been achieved with detector thickness of about 1 mm. A Monte Carlo simulation of neutron reactions in the BN detector was done to estimate the thermal neutron detection efficiency. The result was compared with widely used 3He based detectors to prove advantages of BN detectors, which are especially promising for neutron imaging and for large area sensors.
Show PACS
29.40.Wk Solid-state detectors

On-chip electron-impact ion source using carbon nanotube field emitters

Christopher A. Bower, Kristin H. Gilchrist, Jeffrey R. Piascik, Brian R. Stoner, Srividya Natarajan, Charles B. Parker, Scott D. Wolter, and Jeffrey T. Glass

Appl. Phys. Lett. 90, 124102 (2007); http://dx.doi.org/10.1063/1.2715457 (3 pages) | Cited 13 times

Online Publication Date: 20 March 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A lateral on-chip electron-impact ion source utilizing a carbon nanotube field emission electron source was fabricated and characterized. The device consists of a cathode with aligned carbon nanotubes, a control grid, and an ion collector electrode. The electron-impact ionization of He, Ar, and Xe was studied as a function of field emission current and pressure. The ion current was linear with respect to gas pressure from 10−4 to 10−1 Torr. The device can operate as a vacuum ion gauge with a sensitivity of approximately 1 Torr−1. Ion currents in excess of 1 μA were generated.
Show PACS
79.70.+q Field emission, ionization, evaporation, and desorption
85.35.Kt Nanotube devices

Dynamics of mode competition in a gigawatt-class magnetically insulated line oscillator

D. H. Kim, H. C. Jung, S. H. Min, S. H. Shin, and G. S. Park

Appl. Phys. Lett. 90, 124103 (2007); http://dx.doi.org/10.1063/1.2714992 (3 pages) | Cited 16 times

Online Publication Date: 22 March 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
An axial mode competition is observed in a 1 GHz magnetically insulated line oscillator operating at gigawatt power level with a pulse duration of 130 ns. A fast-growing axial mode adjacent to desired π-mode starts up first and hops to the slow-growing and stable π mode. The dynamics of the mode competition is found to be strongly dependent on the time-varying axial velocity of the magnetically insulated electron beam. The experimental observation is verified by the particle-in-cell simulation using a time-frequency analysis.
Show PACS
84.30.Ng Oscillators, pulse generators, and function generators
84.40.Dc Microwave circuits
02.30.-f Function theory, analysis

Photoluminescence characterization of Zn1−xMgxO epitaxial thin films grown on ZnO by radical source molecular beam epitaxy

H. Shibata, H. Tampo, K. Matsubara, A. Yamada, K. Sakurai, S. Ishizuka, S. Niki, and M. Sakai

Appl. Phys. Lett. 90, 124104 (2007); http://dx.doi.org/10.1063/1.2715475 (3 pages) | Cited 26 times

Online Publication Date: 22 March 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The authors report that high-quality Zn1−xMgxO alloys are very brilliant light emitters, even more brilliant than ZnO, particularly in the high-temperature region; both the emission bandwidth and the oscillator strength of the photoluminescence from Zn1−xMgxO alloys increase remarkably with increasing Mg composition ratio x. The authors have revealed that the increase in the oscillator strength is mainly due to the increase in the activation energy required for the nonradiative recombination processes. Therefore, it is suggested that the localization of excitons, because of the compositional fluctuation, takes place in Zn1−xMgxO alloys and that the degree of the localization increases with increasing x.
Show PACS
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
71.35.-y Excitons and related phenomena
78.66.Hf II-VI semiconductors
78.55.Et II-VI semiconductors

High temperature dielectric study of Cr2O3 in microwave region

D. C. Dube, D. Agrawal, S. Agrawal, and R. Roy

Appl. Phys. Lett. 90, 124105 (2007); http://dx.doi.org/10.1063/1.2716336 (3 pages) | Cited 11 times

Online Publication Date: 23 March 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A unique cavity perturbation method has been used to study the dielectric behavior of chromium oxide (Cr2O3) in the microwave region at ∼ 3.5 GHz and temperatures up to ∼ 1100 °C. The specimen in the form of pellet was heated by microwave power at 2.45 GHz in e-field of a single mode cavity. In the temperature range of measurement, the dielectric constant is found to increase within 10% and loss factor within one and a half times the room temperature values. Results are discussed in the light of agitated ionic motion in the material.
Show PACS
77.22.Ch Permittivity (dielectric function)
77.22.Gm Dielectric loss and relaxation
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close