scholarly journals TIME-RESOLVED CAVITY RINGDOWN MEASUREMENTS OF HO2 RADICAL IN A HEATED PLASMA FLOW REACTOR

2021 ◽  
Author(s):  
Elijah Jans ◽  
Igor Adamovich ◽  
Terry Miller ◽  
Anam Paul ◽  
Xin Yang ◽  
...  
Keyword(s):  
Plasma Flow ◽  
Flow Reactor ◽  
Time Resolved ◽  
Cavity Ringdown

Microcontroller based resonance tracking unit for time resolved continuous wave cavity-ringdown spectroscopy measurements

2012 ◽  
Vol 83 (4) ◽  
pp. 043110 ◽  
Author(s):  
Ondrej Votava ◽  
Milan Mašát ◽  
Alexander E. Parker ◽  
Chaithania Jain ◽  
Christa Fittschen
Keyword(s):  
Continuous Wave ◽  
Cavity Ringdown Spectroscopy ◽  
Time Resolved ◽  
Cavity Ringdown

Time-resolved Cavity Ringdown Spectroscopy as a Monitoring Technique of Nanoparticles in Pulsed VHF Plasmas

2007 ◽  
Vol 989 ◽  
Author(s):  
Takehiko Nagai ◽  
Arno H. M. Smets ◽  
Michio Kondo
Keyword(s):  
Time Scales ◽  
Rayleigh Scattering ◽  
Mie Scattering ◽  
Nano Particles ◽  
Initial Growth ◽  
Time Resolved ◽  
Cavity Ringdown ◽  
Plasma Ignition ◽  
Cavity Loss ◽  
Small Constant

AbstractTime-resolved cavity ringdown (τ-CRD) spectroscopy has been applied to monitor the sylil (SiH3) radicals and nano-particles in pulsed very high frequency (VHF) silane (SiH4)/hydrogen (H2) plasmas under microcrystalline silicon (μc-Si:H) deposition conditions. After the plasma ignition, a small constant cavity loss (~100 ppm) on timescales smaller than ~1 s has been observed, whereas on time scales larger than ~1 s after plasma ignition, an additional cavity loss is observed. By variation of the wavelength of the CRD laser pulse, we demonstrate that the cavity loss on time scales smaller than ~1 s reflects the SiH3 absorption. On time scales larger than ~1 s, the additional cavity loss corresponds to the loss of light due to mainly scattering at the nano-particles. Under the conditions studied, the light scattering at nano-particles can be described by Rayleigh scattering during its initial growth. After ~ 2.5 s, the cavity loss reflects the transition of the scattering mechanism from dominant Rayleigh to dominant Mie-scattering. These results are discussed in terms of nano-particles growing in time and further confirmed by additional scanning electron microscopy analyses on the nano-particles created in the plasma pulse.

scholarly journals Time-Resolved Kinetic Chirped-Pulse Rotational Spectroscopy in a Room-Temperature Flow Reactor

2017 ◽  
Vol 8 (24) ◽  
pp. 6180-6188 ◽  
Author(s):  
Daniel P. Zaleski ◽  
Lawrence B. Harding ◽  
Stephen J. Klippenstein ◽  
Branko Ruscic ◽  
Kirill Prozument
Keyword(s):  
Room Temperature ◽  
Flow Reactor ◽  
Rotational Spectroscopy ◽  
Time Resolved ◽  
Chirped Pulse

scholarly journals Plasma flow reactor studies of H2/O2/Ar kinetics

2016 ◽  
Vol 165 ◽  
pp. 144-153 ◽  
Author(s):  
Nicholas Tsolas ◽  
Kuninori Togai ◽  
Zhiyao Yin ◽  
Kraig Frederickson ◽  
Richard A. Yetter ◽  
...  
Keyword(s):  
Plasma Flow ◽  
Flow Reactor

scholarly journals Fluorescence-detected XAS with sub-second time resolution reveals new details about the redox activity of Pt/CeO2 catalyst

2018 ◽  
Vol 25 (4) ◽  
pp. 989-997 ◽  
Author(s):  
Alexander A. Guda ◽  
Aram L. Bugaev ◽  
Rene Kopelent ◽  
Luca Braglia ◽  
Alexander V. Soldatov ◽  
...  
Keyword(s):  
Time Resolution ◽  
Flow Reactor ◽  
Plug Flow ◽  
Redox Activity ◽  
Time Resolved ◽  
X Ray ◽  
Gas Atmosphere ◽  
Ceria Support ◽  
X Ray Absorption ◽  
Selective Oxidation Catalysts

A setup for fluorescence-detected X-ray absorption spectroscopy (XAS) with sub-second time resolution has been developed. This technique allows chemical speciation of low-concentrated materials embedded in highly absorbing matrices, which cannot be studied using transmission XAS. Using this setup, the reactivity of 1.5 wt% Pt/CeO2 catalyst was studied with 100 ms resolution during periodic cycling in CO- and oxygen-containing atmospheres in a plug-flow reactor. Measurements were performed at the Pt L 3- and Ce L 3-edges. The reactivity of platinum and cerium demonstrated a strong correlation. The oxidation of the catalyst starts on the ceria support helping the oxidation of platinum nanoparticles. The new time-resolved XAS setup can be applied to various systems, capable of reproducible cycling between different states triggered by gas atmosphere, light, temperature, etc. It opens up new perspectives for mechanistic studies on automotive catalysts, selective oxidation catalysts and photocatalysts.

scholarly journals Plasma flow reactor for steady state monitoring of physical and chemical processes at high temperatures

2017 ◽  
Vol 88 (9) ◽  
pp. 093506 ◽  
Author(s):  
Batikan Koroglu ◽  
Marco Mehl ◽  
Michael R. Armstrong ◽  
Jonathan C. Crowhurst ◽  
David G. Weisz ◽  
...  
Keyword(s):  
Steady State ◽  
High Temperatures ◽  
Plasma Flow ◽  
Flow Reactor ◽  
Chemical Processes ◽  
State Monitoring ◽  
Physical And Chemical

Detection of SiH3 radicals and cluster formation in a highly H2 diluted SiH4 VHF plasma by means of time resolved cavity ring down spectroscopy

2006 ◽  
Vol 910 ◽  
Author(s):  
Takehiko Nagai ◽  
Arno H. M. Smets ◽  
Michio Kondo
Keyword(s):  
Growth Rate ◽  
Cluster Formation ◽  
Film Surface ◽  
Growth Conditions ◽  
Time Resolved ◽  
Cavity Ringdown ◽  
Plasma Ignition ◽  
Diffusion Controlled ◽  
Kinetics Of ◽  
Main Growth

AbstractThe spatial distribution of the SiH3 radicals between the electrodes of a hydrogen diluted silane VHF plasma under thin film hydrogenated microcrystalline silicon (μc-Si:H) growth conditions has been measured using the time resolved cavity ringdown (τ-CRD) absorption spectroscopy technique. The μc-Si:H growth rate is estimated from the measured spatial SiH3 profiles using a simple model based upon diffusion controlled flux of SiH3 radicals to the electrode surface, where the SiH3 can react with the film surface. The calculated value of μc-Si:H growth rate roughly agrees with the value of the experimentally determined growth rate. This agreement implies that the SiH3 radical is the main growth contributor to the μc-Si:H growth. Furthermore, the τ-CRD reveals the growth kinetics of the clusters in the plasma by light scattering at these clusters on time scales of 1 s after the plasma ignition.

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