Influence of Surface Roughness on the Light Transmission Through the Boundaries of Luminescent Materials in Radiation Detectors

2021 ◽  
Author(s):  
P. Liaparinos
Keyword(s):  
Surface Roughness ◽  
Light Transmission ◽  
Radiation Detectors ◽  
Luminescent Materials

scholarly journals Influence of surface roughness on the light transmission through the boundaries of luminescent materials in radiation detectors-=SUP=-*-=/SUP=-

2021 ◽  
Vol 129 (9) ◽  
pp. 1182
Author(s):  
P. Liaparinos
Keyword(s):  
Surface Roughness ◽  
Optical Sensors ◽  
Optical Materials ◽  
Light Transmission ◽  
Imaging System ◽  
Radiation Detectors ◽  
Optical Signal ◽  
Transmission Factor ◽  
Luminescent Materials ◽  
Intermediate Surface

The optical transfer properties of an imaging system are affected by the performance of the discrete cascaded system stages that transfer efficiently the optical signal. Apart from the contribution of each component to the overall optical propagation, crucial role also plays the intermediate surface conditions. Surface roughness is characterized by irregularities with respect with the ideal smooth form. The degree of roughness has an influence on the surface behavior affecting correspondingly the overall enhancement of system's optical performance. In this manuscript, the angle dependent effect of surface roughness on phosphor . optical materials configuration is provided taking into account eight luminescent materials (CsI, Y3Al5O12, Y2O3, Bi4Ge3O12, CaWO4, ZnS, Lu2O3 and Gd2O2S) and three optical materials (InGaAs, ITO and SiO2). Results showed that higher transmission optical properties exhibited the: (i) CsI-InGaAs combination, (ii) ZnS-ITO and (iii) ZnS-SiO2 combination. The transmission factor was also quantitatively affected by increasing the surface roughness values and by decreasing the incident polar angles. Keywords: luminescent materials, optical sensors, surface roughness

Surface roughness and light transmission of biaxially oriented polypropylene films

2007 ◽  
Vol 47 (10) ◽  
pp. 1658-1665 ◽  
Author(s):  
Y.J. Lin ◽  
P. Dias ◽  
S. Chum ◽  
A. Hiltner ◽  
E. Baer
Keyword(s):  
Surface Roughness ◽  
Light Transmission ◽  
Biaxially Oriented Polypropylene ◽  
Oriented Polypropylene ◽  
Polypropylene Films

scholarly journals Effect of chemical etching on the surface roughness of CdZnTe and CdMnTe gamma radiation detectors

2008 ◽  
Author(s):  
A. Hossain ◽  
S. Babalola ◽  
A. E. Bolotnikov ◽  
G. S. Camarda ◽  
Y. Cui ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Gamma Radiation ◽  
Chemical Etching ◽  
Radiation Detectors

Nano-finishing of MEMS-based platforms for optimum optical sensing

2019 ◽  
Vol 3 (1) ◽  
pp. 39-53
Author(s):  
Ankur Gupta ◽  
Poonam Sundriyal ◽  
Aviru Basu ◽  
Kapil Manoharan ◽  
Rishi Kant ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Refractive Index ◽  
Surface Finish ◽  
Microelectromechanical Systems ◽  
Transmission Loss ◽  
Light Transmission ◽  
Visible Spectrum ◽  
Grazing Incidence ◽  
Wet Etching ◽  
Etching Technique

The surface finish of the microelectromechanical systems substrate, particularly the ones that are deployed in chip-based optofluidic systems, is of utmost importance, and the overall surface finish helps in preventing light scattering and associated losses. The proposed system is made up of a microchannel with a coating on its interior which acts as a cladding layer and possesses an air-like refractive index. The water-based solutions with refractive indices higher than the coating, when confined within such channels, act as waveguides with a refractive index difference which would allow grazing incidence at the solution film interface. The microchannel is fabricated over a piece of Si along <100> direction with the help of lithography and wet etching technique. After wet chemical etching of silicon, multiple pyramidal hillocks with overall large surface roughness is observed which are not appropriate for loss-free light transmission and cause various optical losses. So the overall optimization of surface roughness created by the etching processes is critical from an optical standpoint. Roughness in the microchannel surface mainly arises due to wet etching through tetra methyl alcohol, potassium hydroxide, potassium ferricyanide and isopropyl alcohol. In this work, we have obtained surface finish upto ~1.33 nm at an etch rate of 141 nm/min which is obtained by tweaking the composition of the participating reagents in the etchants and also the etching temperature. The surface roughness obtained is quite small in comparison to the wavelength range of the visible spectrum and thus losses were greatly avoided. The low refractive index films over silicon substrate were characterized by field emission scanning electron microscopy, energy dispersive analysis of X-ray, atomic force microscopy, 3D optical profilometry and ellipsometry. The transmission results show that transmission loss was reduced by 27.42% for the coated samples with 33 nm surface roughness as compared to surface with 250 nm roughness.

Signal Amplification and Leakage Current Suppression in Amorphous Silicon P-I-N Diodes by Field Profile Tailoring

1999 ◽  
Vol 557 ◽  
Author(s):  
W.S. Hong ◽  
F. Zhong ◽  
A. Mireshghi ◽  
V. Perez-Mendez
Keyword(s):  
Amorphous Silicon ◽  
Leakage Current ◽  
Electric Fields ◽  
Light Transmission ◽  
Signal Amplitude ◽  
Radiation Detectors ◽  
Metallic Contact ◽  
Fully Depleted ◽  
Avalanche Gain ◽  
Order Of Magnitude

AbstractThe performance of amorphous silicon p-i-n diodes as radiation detectors in terms of signal amplitude can be greatly improved when there is a built-in signal gain mechanism. We describe an avalanche gain mechanism which is achieved by introducing stacked intrinsic, p-type, and n-type layers into the diode structure. We replaced the intrinsic layer of the conventional p-i-n diode with i1-p-i2-n-i3 multilayers. The i2 layer (typically 1~3 μm) achieves an electric field > 106 V/cm, while maintaining the p-i interfaces to the metallic contact at electric fields < 7 × 104 V/cm, when the diode is fully depleted. For use in photo-diode applications the whole structure is less than 10 μm thick. Avalanche gains of 10~50 can be obtained when the diode is biased to ~500 V. Also, dividing the electrodes to strips of 2 μm width and 20 μm pitch reduced the leakage current up to an order of magnitude, and increased light transmission without creating inactive regions.

Advanced TEM sample preparation techniques for submicron Si devices

1995 ◽  
Vol 53 ◽  
pp. 516-517 ◽  
Author(s):  
P. B. Basham ◽  
H. L. Tsai
Keyword(s):  
Sample Preparation ◽  
Process Development ◽  
Light Transmission ◽  
Specific Area ◽  
Turnaround Time ◽  
Small Hole ◽  
Area Of Interest ◽  
Transmission Electron ◽  
Polished Side ◽  
Preparation Techniques

The use of transmission electron microscopy (TEM) to support process development of advanced microelectronic devices is often challenged by a large amount of samples submitted from wafer fabrication areas and specific-spot analysis. Improving the TEM sample preparation techniques for a fast turnaround time is critical in order to provide a timely support for customers and improve the utilization of TEM. For the specific-area sample preparation, a technique which can be easily prepared with the least amount of effort is preferred. For these reasons, we have developed several techniques which have greatly facilitated the TEM sample preparation.For specific-area analysis, the use of a copper grid with a small hole is found to be very useful. With this small-hole grid technique, TEM sample preparation can be proceeded by well-established conventional methods. The sample is first polished to the area of interest, which is then carefully positioned inside the hole. This polished side is placed against the grid by epoxy Fig. 1 is an optical image of a TEM cross-section after dimpling to light transmission.

Roughness measurements of nonlinear optical polymer films by scanning tunneling microscopy

1989 ◽  
Vol 47 ◽  
pp. 22-23
Author(s):  
I. H. Musselman ◽  
R.-T. Chen ◽  
P. E. Russell
Keyword(s):  
Surface Roughness ◽  
Scanning Tunneling Microscopy ◽  
Nonlinear Optical ◽  
Polymer Surface ◽  
Light Extinction ◽  
Scanning Tunneling ◽  
Silicon Substrates ◽  
Tunneling Microscopy ◽  
Optical Polymer ◽  
Total Light

Scanning tunneling microscopy (STM) has been used to characterize the surface roughness of nonlinear optical (NLO) polymers. A review of STM of polymer surfaces is included in this volume. The NLO polymers are instrumental in the development of electrooptical waveguide devices, the most fundamental of which is the modulator. The most common modulator design is the Mach Zehnder interferometer, in which the input light is split into two legs and then recombined into a common output within the two dimensional waveguide. A π phase retardation, resulting in total light extinction at the output of the interferometer, can be achieved by changing the refractive index of one leg with respect to the other using the electrooptic effect. For best device performance, it is essential that the NLO polymer exhibit minimal surface roughness in order to reduce light scattering. Scanning tunneling microscopy, with its high lateral and vertical resolution, is capable of quantifying the NLO polymer surface roughness induced by processing. Results are presented below in which STM was used to measure the surface roughness of films produced by spin-coating NLO-active polymers onto silicon substrates.

Role of the exosporial membrane in attachment and germination of C. sporogenes

1993 ◽  
Vol 51 ◽  
pp. 38-39
Author(s):  
B.J. Panessa-Warren ◽  
G.T. Tortora ◽  
J.B. Warren
Keyword(s):  
Enzymatic Degradation ◽  
Light Transmission ◽  
Extended Period ◽  
Growth Conditions ◽  
Clostridium Sporogenes ◽  
Radiation Chemical ◽  
Physical Trauma ◽  
Extended Contact ◽  
Cold Pressure

Some bacteria are capable of forming highly resistant spores when environmental conditions are not adequate for growth. Depending on the genus and species of the bacterium, these endospores are resistant in varying degrees to heat, cold, pressure, enzymatic degradation, ionizing radiation, chemical sterilants,physical trauma and organic solvents. The genus Clostridium, responsible for botulism poisoning, tetanus, gas gangrene and diarrhea in man, produces endospores which are highly resistant. Although some sporocides can kill Clostridial spores, the spores require extended contact with a sporocidal agent to achieve spore death. In most clinical situations, this extended period of treatment is not possible nor practical. This investigation examines Clostridium sporogenes endospores by light, transmission and scanning electron microscopy under various dormant and growth conditions, cataloging each stage in the germination and outgrowth process, and analyzing the role played by the exosporial membrane in the attachment and germination of the spore.

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