Dissolution characteristics of poly(methyl methacrylate) as an X-ray resist

1987 ◽  
Vol 65 (8) ◽  
pp. 975-978 ◽  
Author(s):  
E. M. Lehockey ◽  
J. D. Wice ◽  
I. Reid
Keyword(s):  
Methyl Methacrylate ◽  
Dissolution Rate ◽  
Chain Scission ◽  
X Rays ◽  
X Ray ◽  
Poly Methyl Methacrylate ◽  
Dose Rates ◽  
Main Requirement ◽  
Relative Measurements ◽  
First Time

A reversion in the dissolution characteristics of X-ray irradiated poly(methyl methacrylate) (PMMA) is shown experimentally, and a model is developed to explain the behaviour. The PMMA has been irradiated with 11 kV Cu X-rays to doses up to 240 μA∙min∙cm−2 at dose rates of 4 and 8 μA∙cm−2. The doses are determined by photoelectron emission and are therefore only relative measurements. The dissolution rate of the irradiated PMMA in a 1:2 developer of methyl isobutyl ketone and isopropyl alcohol is measured as a function of X-ray dose. For the first time, a model is developed that predicts this reversion in the dissolution rate. For the model to predict a reversion point, it is necessary to treat the processes of chain scission and cross-linking as operating on separate sites. The main requirement here is that cross-linked bonds do not become sites for scission. If this requirement is not made, no reversion is predicted.

LIGA Technologies and Applications

MRS Bulletin ◽  
2001 ◽  
Vol 26 (4) ◽  
pp. 337-340 ◽  
Author(s):  
Jill Hruby
Keyword(s):  
Synchrotron Radiation ◽  
Methyl Methacrylate ◽  
Light Source ◽  
High Energy ◽  
X Rays ◽  
Electromechanical Systems ◽  
X Ray ◽  
Poly Methyl Methacrylate

LIGA, an acronym for the German words for lithography, electroplating, and molding, is a technique used to produce micro-electromechanical systems (MEMS) made from metals, ceramics, or plastics. The LIGA process utilizes x-ray synchrotron radiation as a lithographic light source. Highly collimated, high-energy x-rays from the synchrotron impinge on a patterned mask in proximity to an x-ray-sensitive photoresist, typically poly(methyl methacrylate) (PMMA).

ABLATION OF POLY(METHYL METHACRYLATE) BY A SINGLE PULSE OF SOFT X-RAYS EMITTED FROM Z-PINCH AND LASER-PRODUCED PLASMAS

2002 ◽  
Vol 09 (01) ◽  
pp. 347-352 ◽  
Author(s):  
L. JUHA ◽  
J. KRÁSA ◽  
A. PRÄG ◽  
A. CEJNAROVÁ ◽  
D. CHVOSTOVÁ ◽  
...  
Keyword(s):  
Methyl Methacrylate ◽  
Single Pulse ◽  
Polymer Structure ◽  
Molecular Fragment ◽  
X Rays ◽  
Radiation Chemical ◽  
X Ray ◽  
Poly Methyl Methacrylate ◽  
Promising Application ◽  
Z Pinch

The efficiency of ablation induced in poly(methyl methacrylate) (PMMA) by single soft X-ray pulses emitted from Z-pinch and laser-produced plasmas was determined. X-ray ablation of PMMA was found to be less efficient than that of teflon (PTFE). Nonthermal effects of the radiation on the polymer structure play a key role in the mechanisms of the ablation, i.e. the ablation can be explained by the formation of radiation-chemical scissions of the polymer chain followed by blowoff of low-molecular fragment fluid into the vacuum. The most promising application of this phenomenon seems to be micropatterning/micromachining.

scholarly journals Observations of X-rays from Laboratory Sparks in Air at Atmospheric Pressure under Negative Switching Impulse Voltages

Atmosphere ◽  
2019 ◽  
Vol 10 (4) ◽  
pp. 169 ◽  
Author(s):  
Mahbubur Rahman ◽  
Pasan Hettiarachchi ◽  
Vernon Cooray ◽  
Joseph Dwyer ◽  
Vladimir Rakov ◽  
...  
Keyword(s):  
Rise Time ◽  
Atmospheric Pressure ◽  
Opposite Polarity ◽  
X Rays ◽  
X Ray ◽  
Impulse Voltage ◽  
First Time ◽  
Switching Impulses ◽  
Low Rate

We present observations of X-rays from laboratory sparks created in the air at atmospheric pressure by applying an impulse voltage with long (250 µs) rise-time. X-ray production in 35 and 46 cm gaps for three different electrode configurations was studied. The results demonstrate, for the first time, the production of X-rays in gaps subjected to switching impulses. The low rate of rise of the voltage in switching impulses does not significantly reduce the production of X-rays. Additionally, the timing of the X-ray occurrence suggests the possibility that the mechanism of X-ray production by sparks is related to the collision of streamers of opposite polarity.

Mesoscopic structure of SiC fibers by neutron and x-ray scattering

1996 ◽  
Vol 11 (5) ◽  
pp. 1169-1178 ◽  
Author(s):  
Kentaro Suzuya ◽  
Michihiro Furusaka ◽  
Noboru Watanabe ◽  
Makoto Osawa ◽  
Kiyohito Okamura ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Volume Fraction ◽  
X Rays ◽  
X Ray ◽  
Sic Fibers ◽  
X Ray Scattering ◽  
Mesoscopic Structure ◽  
Angle Scattering ◽  
Momentum Transfer Range ◽  
First Time

Mesoscopic structures of SiC fibers produced from polycarbosilane by different methods were studied by diffraction and small-angle scattering of neutrons and x-rays. Microvoids of a size of 4–10 Å in diameter have been observed for the first time by neutron scattering in a medium momentum transfer range (Q = 0.1–1.0 Å−1). The size and the volume fraction of β–SiC particles were determined for fibers prepared at different heat-treatment temperatures. The results show that wide-angle neutron scattering measurements are especially useful for the study of the mesoscopic structure of multicomponent materials.

Properties of Carbon Nanofibers Prepared from Polyacrylonitrile/Poly(methyl Methacrylate) Blend

2009 ◽  
Vol 79-82 ◽  
pp. 353-356
Author(s):  
Wei Pan ◽  
Yan Chen ◽  
Xiao Wei He
Keyword(s):  
Methyl Methacrylate ◽  
Carbon Nanofibers ◽  
Carbon Fibers ◽  
Nitrogen Atmosphere ◽  
Wet Spinning ◽  
X Ray Diffraction ◽  
X Ray ◽  
Poly Methyl Methacrylate ◽  
Graphite Crystallite ◽  
Raman Microspectrometry

The polyacrylonitrile(PAN)/poly (methyl methacrylate)(PMMA) blend fibers were prepared by wet-spinning technique and carbonized over the temperature range of 400-1000°C in nitrogen atmosphere. After carbonization of the blend fibers, the PMMA component removed and the PAN component left in the form of carbon nanofibers. Morphology of the carbon nanofibers were investigated via scanning electron microscopy (SEM), and the carbonization behavior of the fibers were examined via x-ray diffraction (XRD), Raman microspectrometry. The optimal condition made carbon fibers with great L/D ratio and diameter less than 200 nm. XRD and Raman spectra shows that the PAN/PMMA blend fibers treated at 600°C produced some graphite crystallite.

scholarly journals Optical Short-Time Variations in GK Persei during the 1983 Outburst

1987 ◽  
Vol 93 ◽  
pp. 485-485
Author(s):  
H. Steinle ◽  
W. Pietsck
Keyword(s):  
Accretion Disk ◽  
Time Resolution ◽  
X Rays ◽  
X Ray ◽  
Time Variations ◽  
Short Time ◽  
First Time ◽  
Calar Alto

AbstractDuring the August 1983 outburst of the old nova GK Persei observations with EXOSAT showed for the first time a 351 second periodicity in X-rays.Our fast photometry (U(B)V with 25 sec time resolution) was made at the end of the outburst in the nights of September 29 , and October 1–3 , using the 2.2 meter telescope at Calar Alto (Spain).Optical variations up to 10% in U and 4% in V with periodicities in the range 350 to 360 seconds were found, lasting only for few cycles.A comparison with the extrapolated prediction of the X-ray maxima did not show a coincidence, but rather an anticoincidence in several cases. This supports a model of reprocessed X-rays at the inner edge of an accretion disk.

scholarly journals The 3XMM/SDSS Stripe 82 Galaxy Cluster Survey – II. X-ray and optical properties of the cluster sample

2019 ◽  
Vol 486 (4) ◽  
pp. 4863-4879 ◽  
Author(s):  
Ali Takey ◽  
Florence Durret ◽  
Isabel Márquez ◽  
Amael Ellien ◽  
Mona Molham ◽  
...  
Keyword(s):  
Optical Properties ◽  
Galaxy Cluster ◽  
X Rays ◽  
Present Sample ◽  
X Ray ◽  
Cluster Galaxies ◽  
Cluster Survey ◽  
Cluster Sample ◽  
Cluster Mass ◽  
First Time

ABSTRACT We present X-ray and optical properties of the optically confirmed galaxy cluster sample from the 3XMM/SDSS Stripe 82 cluster survey. The sample includes 54 galaxy clusters in the redshift range of 0.05–1.2, with a median redshift of 0.36. We first present the X-ray temperature and luminosity measurements that are used to investigate the X-ray luminosity–temperature relation. The slope and intercept of the relation are consistent with those published in the literature. Then, we investigate the optical properties of the cluster galaxies including their morphological analysis and the galaxy luminosity functions (GLFs). The morphological content of cluster galaxies is investigated as a function of cluster mass and distance from the cluster centre. No strong variation of the fraction of early- and late-type galaxies with cluster mass is observed. The fraction of early-type galaxies as a function of cluster radius varies as expected. The individual GLFs of red sequence galaxies were studied in the five ugriz bands for 48 clusters. The GLFs were then stacked in three mass bins and two redshift bins. Twenty clusters of the present sample are studied for the first time in X-rays, and all are studied for the first time in the optical range. Altogether, our sample appears to have X-ray and optical properties typical of ‘average’ cluster properties.

scholarly journals A New Chapter in Hard X-rays of the M87 AGN

Proceedings ◽  
2019 ◽  
Vol 17 (1) ◽  
pp. 9
Author(s):  
Ka-Wah Wong ◽  
Rodrigo S. Nemmen ◽  
Jimmy A. Irwin ◽  
Dacheng Lin
Keyword(s):  
High Energy ◽  
X Rays ◽  
X Ray ◽  
Accretion Flow ◽  
Relativistic Jet ◽  
Very High Energy ◽  
Γ Ray ◽  
High Energy Emission ◽  
First Time ◽  
Very High

The nearby M87 hosts an exceptional relativistic jet. It has been regularly monitored in radio to TeV bands, but little has been done in hard X-rays ≳10 keV. For the first time, we have successfully detected hard X-rays up to 40 keV from its X-ray core with joint Chandra and NuSTAR observations, providing important insights to the X-ray origins: from the unresolved jet or the accretion flow. We found that the hard X-ray emission is significantly lower than that predicted by synchrotron self-Compton models introduced to explain very-high-energy γ -ray emission above a GeV. We discuss recent models to understand these high energy emission processes.

scholarly journals NuSTAR reveals that the heavily obscured nucleus of NGC 2785 was the contaminant of IRAS 09104+4109 in the BeppoSAX/PDS hard X-rays

2018 ◽  
Vol 619 ◽  
pp. A16
Author(s):  
C. Vignali ◽  
P. Severgnini ◽  
E. Piconcelli ◽  
G. Lanzuisi ◽  
R. Gilli ◽  
...  
Keyword(s):  
X Rays ◽  
X Ray ◽  
Star Forming ◽  
Physical Description ◽  
Enhanced Sensitivity ◽  
X Ray Imaging ◽  
First Time ◽  
In Virtue Of

Context. The search for heavily obscured active galactic nuclei has been revitalized in the last five years by NuSTAR, which has provided a good census and spectral characterization of a population of such objects, mostly at low redshift, thanks to its enhanced sensitivity above 10 keV compared to previous X-ray facilities, and its hard X-ray imaging capabilities. Aims. We aim at demonstrating how NGC 2785, a local (z = 0.009) star-forming galaxy, is responsible, in virtue of its heavily obscured active nucleus, for significant contamination in the non-imaging BeppoSAX/PDS data of the relatively nearby (≈17′) quasar IRAS 09104+4109 (z = 0.44), which was originally mis-classified as Compton thick. Methods. We analyzed ≈71 ks NuSTAR data of NGC 2785 using the MYTorus model and provided a physical description of the X-ray properties of the source for the first time. Results. We found that NGC 2785 hosts a heavily obscured (NH ≈ 3 × 1024 cm−2) nucleus. The intrinsic X-ray luminosity of the source, once corrected for the measured obscuration (L2−10keV ≈ 1042 erg s−1), is consistent within a factor of a few with predictions based on the source mid-infrared flux using widely adopted correlations from the literature. Conclusions. Based on NuSTAR data and previous indications from the Neil Gehrels Swift Observatory (BAT instrument), we confirm that NGC 2785, because of its hard X-ray emission and spectral shape, was responsible for at least one third of the 20–100 keV emission observed using the PDS instrument onboard BeppoSAX, originally completely associated with IRAS 09104+4109. Such emission led to the erroneous classification of this source as a Compton-thick quasar, while it is now recognized as Compton thin.

Small-angle x-ray scattering investigation of poly(methyl methacrylate)-alumina nanocomposite

2019 ◽  
Author(s):  
Jitendra Bahadur ◽  
S. K. Sharma ◽  
Avik Das ◽  
Debasis Sen ◽  
P. K. Pujari
Keyword(s):  
Methyl Methacrylate ◽  
Small Angle ◽  
X Ray ◽  
Poly Methyl Methacrylate ◽  
X Ray Scattering ◽  
Ray Scattering
Sign in / Sign up

Export Citation Format

Share Document