scholarly journals Optimum detector distance for neutron TOF (time-of-flight) temperature measurements

1989 ◽  
Author(s):  
R. Lerche
Keyword(s):  
Time Of Flight ◽  
Temperature Measurements ◽  
Detector Distance

Ion temperature measurements of indirect-drive implosions with the neutron time-of-flight detector on SG-III laser facility

2018 ◽  
Vol 89 (2) ◽  
pp. 023504 ◽  
Author(s):  
Zhongjing Chen ◽  
Xing Zhang ◽  
Yudong Pu ◽  
Ji Yan ◽  
Tianxuan Huang ◽  
...  
Keyword(s):  
Time Of Flight ◽  
Temperature Measurements ◽  
Ion Temperature ◽  
Laser Facility ◽  
Indirect Drive ◽  
Neutron Time

Recession Experiments and Modeling for Carbon Surface Oxidation Processes

2013 ◽  
Author(s):  
Andrew Kurzawski ◽  
Ofodike A. Ezekoye ◽  
Joseph H. Koo ◽  
Colin Yee ◽  
Theodore Hardee
Keyword(s):  
Temperature Profile ◽  
Time Of Flight ◽  
Synthetic Data ◽  
Temperature Measurements ◽  
Carbon Surface ◽  
High Heat Flux ◽  
Sample Length ◽  
Spatial Integration ◽  
Recession Rate ◽  
Flight Measurement

We examined numerical and experimental use of a coupled-transducer system comprised of a thermocouple temperature measurements and time of flight acoustic measurements to determine the recession rate of a carbon material. A problem in the use of ultrasonic transducers for high temperature thickness measurements is that the temperature of the specimen is not always known. The variation of the speed of sound with temperature makes this a challenging problem and the use of a limited number of temperature measurements helps to construct a temperature profile on which the acoustic time of flight measurement can be characterized. In the problem of interest, a high heat flux is directed towards the surface of a carbon based material. A temperature profile is set up in the material. Initially the heated face simply increases in temperature with no mass loss. With increasing heating and oxygen transport to the surface, the hot face begins to oxidatively erode. Temperature measurements Y (xi) are made at xi locations within the material. At the same time a time of flight measurement is made in the material. We can assume that the time of flight measurement takes place over a time period that is small relative to the time for which the spatial temperature variation evolves. As such, the time of flight measurement primarily involves a weighted spatial integration of a function of temperature. Given the temperature measurements and the time of flight measurement, we seek the recession rate or equivalently, the sample length. We develop a simple thermal model with appropriate representation of oxidation kinetics to describe the process. A simple inversion analysis is developed and tested on synthetic data to best fit the experimental data.

Ion-temperature measurements of direct-drive implosions using a neutron time-of-flight detector at the SG-II upgrade facility

2019 ◽  
Vol 14 (05) ◽  
pp. P05018-P05018
Author(s):  
E.-F. Guo ◽  
J.-Q. Dong ◽  
J.-B. Chen ◽  
Chen Wang ◽  
H.-H. An ◽  
...  
Keyword(s):  
Time Of Flight ◽  
Temperature Measurements ◽  
Direct Drive ◽  
Ion Temperature ◽  
Neutron Time

Applications of Time-OF-Flight Secondary Ion Mass Spectrometry (TOF-SIMS)

1990 ◽  
Vol 48 (2) ◽  
pp. 308-309
Author(s):  
Bruno Schueler ◽  
Robert W. Odom
Keyword(s):  
Mass Spectrometry ◽  
Secondary Ion Mass Spectrometry ◽  
Structural Information ◽  
Time Of Flight ◽  
Biological Tissues ◽  
Polymer Surfaces ◽  
Tof Sims ◽  
Secondary Ions ◽  
Ion Mass Spectrometry ◽  
Secondary Ion

Time-of-flight secondary ion mass spectrometry (TOF-SIMS) provides unique capabilities for elemental and molecular compositional analysis of a wide variety of surfaces. This relatively new technique is finding increasing applications in analyses concerned with determining the chemical composition of various polymer surfaces, identifying the composition of organic and inorganic residues on surfaces and the localization of molecular or structurally significant secondary ions signals from biological tissues. TOF-SIMS analyses are typically performed under low primary ion dose (static SIMS) conditions and hence the secondary ions formed often contain significant structural information.This paper will present an overview of current TOF-SIMS instrumentation with particular emphasis on the stigmatic imaging ion microscope developed in the authors’ laboratory. This discussion will be followed by a presentation of several useful applications of the technique for the characterization of polymer surfaces and biological tissues specimens. Particular attention in these applications will focus on how the analytical problem impacts the performance requirements of the mass spectrometer and vice-versa.

Assessment of extracranial-intracranial bypass in Moyamoya disease using 3T time-of-flight MR angiography: Comparison with CT angiography

VASA ◽  
2014 ◽  
Vol 43 (4) ◽  
pp. 278-283 ◽  
Author(s):  
Qian Chen ◽  
Rongfeng Qi ◽  
Xiaoqing Cheng ◽  
Changsheng Zhou ◽  
Song Luo ◽  
...  
Keyword(s):  
Image Quality ◽  
Moyamoya Disease ◽  
Mr Angiography ◽  
Time Of Flight ◽  
Consecutive Series ◽  
Tof Mra ◽  
Bypass Patency ◽  
Significant Difference ◽  
Contrast Technique ◽  
Vessel Integrity

Background: To evaluate the value of time-of-flight MR angiography (TOF MRA) for the assessment of extracranial-intracranial (EC-IC) bypass in Moyamoya disease in comparison with computed tomography angiography (CTA). Patients and methods: A consecutive series of 23 patients with Moyamoya disease were analyzed retrospectively. Twenty three patients underwent 25 procedures of extracranial-intracranial bypass. Cranial CTA was performed within one week after the surgery to assess bypass patency. Then TOF MRA was scanned within 24 h after CTA on a 3T MRI system. Using 5-point scales (0 = poor to 4 = excellent), two radiologists rated the image quality and vessel integrity of bypass for three segments (extracranial, trepanation, intracranial). Results: Image quality was high in both CTA and TOF MRA (mean quality score 3.84 ± 0.37 and 3.8 ± 0.41), without statistical difference (p = 0.66). Mean scores of TOF MRA with respect to bypass visualization were higher than CTA in the intracranial segment (p = 0.026). No significant difference of bypass visualization regarding the extracranial and trepanation segments was found between TOF MRA and CTA (p = 0.66 and p = 0.34, respectively). For the trepanation segment, TOF MRA showed pseudo lesions in 2 of all 25 cases. Conclusions: 3T TOF MRA, a non-contrast technique not exposing the patients to radiation, proved to be at least equal to CTA for the assessment of EC-IC bypass, and even superior to CTA with respect to the intracranial segment. In addition, readers should be aware of a potential overestimation showing focal pseudo lesions of the bypass at the trepanation segment in TOF MRA.

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