Praying Mantis Diffuse Reflectance Accessory

The world leader in serving science 

UV/VIS 

spectrometers 

accessories for solid 

samples

• Measuring of solid samples: 

• Transmission 

• Diffuse Transmission 

• Diffuse Reflexion 

• Specula Reflexion 

Erich Heiden UV/Vis Salesmanager 

2

Solid Sample Measurement – Diffuse Transmittance 

Unique !! 

• Magnetic base is drilled with ¼-20 holes on a 1” grid 

• Like a laser table 

• Use standard laser table mounting hardware for your samples 

• Integrating sphere means you can alter 

the shape and focus of the beam 

• Measure curved optics 

• Add small spot kit or additional optics to 

get the beam into the port 

• This is something that you can’t do with a 

conventional instrument 


3

Scattered Transmission 

• Scattered Transmission is a measurement performed on a 

material that causes transmitted light to scatter 

• Solid materials could be: 

• Plastic films or sheets, e.g., pharmaceutical bottles, plastics, etc. 

• Fabrics for UV Protection 

• Sunscreen lotions 

• Scattered Transmission measurements are performed using the 

Integrating sphere on the Evolution 600 spectrophotometer 


4

Haze (ASTM D 1003-00) 

• Haze is the percentage of transmitted light which, when passing 

through a sample, deviates from the incident beam by forward 

scattering. Lower haze values imply greater transparency. 

• Haze is an important property when designing for a transparent 

application in which observers must be able to see inside or 

through a part easily and clearly. If a material has a high haze 

value, it will have decreased transparency – making it more 

difficult to see inside or behind the sample. A sample with a 

high haze value will still transmit light, but images may appear 

foggy or blurred. 

• Typically, polycarbonate resins have a haze value of about 0.5 to 

2.0%. Haze value ranges for other transparent materials are: 

• Polystyrene: 0.1 to 3.0% 

• Styrene acrylonitrile: 0.6 to 3.0% 

• Polymethylmethacrylate: 1.0 to 3.0% 

• Cellulose acetate: 0.5 to 5.0% 

• Glass: 0 to 0.17% 


5

Haze Measurements on Plastic Film 

Scattering effect 


6

Transmittance Calculation in VL MaterialsCalc 

Oakley ® +Red Iridium Sunglasses 

Manufacturer Data 

+Red Iridium is a Trademark of Oakley, Inc. 


7

Transmittance Calculation in VL MaterialsCalc 

Oakley ® Gold Iridium Sunglasses 

Manufacturer Data 

Gold Iridium is a Trademark of Oakley, Inc. 


8




• Diffuse Reflexion 

• Specular Reflexion 


9

Solid Sample Measurement – Diffuse Reflectance 

• Integrating Spheres 

• Turbid solutions 

• Color (true color Evo600 only) 

• Diffuse reflectance 

• Praying Mantis 

• Diffuse reflectance accessory 

• Small samples, heating/cooling, 

• Catalyst research 


10

DRA-EV-600 Integrating Sphere 

For Evolution 600 

• Upward viewing 

• Spectralon coating 

• Sample mounts on top 

• Unrestricted sample size 


11

How do you measure how good a sphere is? 

• Sphere Multiplier “M” – a measure of the efficiency of 

the sphere. 

• Calculated from the reflectivity and the port fraction. 

• Bigger is better 

• M isn’t everything 

• Think of the light being diluted across the surface of the sphere 

• Light is more concentrated in a smaller sphere 

Sphere diameter 

Sphere Surface 

Area (mm 2 ) 

Port Fraction 

f 

Sphere Multiplier 

M 

% of incident light falling on 

64 mm 2 detector port 

60 mm 11310 11.3 8.1 4.6 

70 mm 15394 9.3 9.7 4.0 

75 mm 17671 3.6 21.7 7.9 

150 mm 70686 2.5 28.5 2.6 


12

Horizontal reflectance port – a competitive advantage 

• Reflectance port is outside the 

sample compartment 

• Easy to measure the 

reflectance of a specific spot 

on the sample 

• Easy to mount and measure 

the same spot on the sample 

• Remove the sample and relocate 

to the same spot 

• Delicate samples can be 

measured easily 

• Sample held in place by 

gravity only 


13

Diffuse Reflectance measurements of granular materials 

• Powder Cell holder kit 

• Requires 1-2 mm sample 

thickness 

• Use o-rings to reduce required 

volume and/or seal to the 

atmosphere 

• Measure powders, plastic pellets, 

crystals, etc 

• Kit includes powder cell holder 

and Spectralon® powder cell 

holder for calibration 

measurements 

Insert to reduce powder volume required 


14

DRA-EV-600 Integrating Sphere 

Defining features 

• Upward viewing sample reflectance port 

• Horizontal sample mounting 

• Maximum sample size limited only by your ability to secure 

the sample and shield from room light 

• Routine samples easily fit inside the standard light shield 

cover 

• Double beam sphere 

• 75 mm internal diameter 

• 8 degrees sample illumination with option to 

include/exclude Sample Specular component 

• Spectralon® coated sphere for highest 

possible reflectivity and longevity 

• Port Fraction: 3.6% (reflectance), 2.9% 

(transmittance) 

• CIE compliant for Color measurements 

• Haze compliant for ASTM 1003 Transmittance of Plastics 


15

Diffuse Reflectance 

• An ideal diffuse reflectance 

surface reflects and scatters light 

in all directions. 

• Examples of excellent diffuse 

reflectors include 

• matte paint 

• unglazed ceramics 

• packed powders 

• etched metal surfaces 

• Any surface that is made up of 

stabilized or compacted particles 

is likely to be a diffuse reflector 


16

Diffuse Reflectance Applications 

• Analyze powders or crystals by 

reflectance 

• Paint or ink color 

• Surface gloss or texture 

• Electronic properties of solids 

• Electronic properties of surface films 

• Eliminates possible solvent effects 

• E.g., Inorganic metal complexes subject to solvent 

substitution for ligands in solution 

• Analyze optical or microelectronic 

materials by transmission or reflectance 

• Quality control measurements to 

determine product quality 

• R&D for developing new materials 


17

Diffuse Reflectance Applications 


18

Comparison of Different Sunscreens 


19

SPF Calculation in VL MaterialsCalc 

SPF 8 Sunscreen 


20

Calculation in VL MaterialsCalc 

SPF 50 Sunscreen with Broad Spectrum Protection 


21

UV Protection Fabrics 

• What is UV Protection Factor? 

• The Ultraviolet Protection Factor (or UPF) rating system measures 

the UV protection provided by fabric 

• It is very similar to the SPF rating system used for sunscreens 

• For example: A garment with a UPF of 50 only allows 1/50th of the UV radiation falling 

on the surface of the garment to pass through it. 

In other words, it blocks 49/50ths or 98% of the UV radiation 

• Who makes UPF measurements? 

• Manufacturers of Sun Protection Fabric 

• Manufacturers of Sun Protection Garments 

• Independent testing facilities 

• Government Regulatory Agencies (ASTM, ARPANSA, etc.) 

• Target ALL fabric and clothing manufacturers 

http://www.coolibar.com/upf-ratings.html 


22

UPF Regulations 

• Australian/New Zealand 

Standard 4399 

• Enforced by ARPANSA 

• Uses raw fabric – easy to comply 

with. 

• ASTM D 6544 - Voluntary 

• ASTM D 6603 - Voluntary 

• AATCC Method 183 – Voluntary 

• Used for “Outdoor Research” 

brand products sold at REI. 

• Requires 40 washes and wet as 

well as dry testing – more effort 

to comply with. 

• In the US, while the FDA 

regulates sunscreens, there is 

presently no Federal program for 

sun protective garments 


23

Factors Affecting UPF Measurements 

• Addition of chemicals such as UV absorbers or UV diffusers 

during the manufacturing process 

• weave -- tighter is better 

• color -- darker is better 

• weight -- heavier is better 

• stretch -- less stretch is better 

• wetness -- dry is better 


24

UPF Calculations 

• Baseline measured with fluorescence 

filter (UG-11) in place 

• Fabric measured in taut but not 

stretched condition 

• Areas of different color are measured 

independently 

• Measurements taken with and against 

the weave and averaged together 

• Variation must be within specified 

statistical limits in standard 


25




• Diffuse Reflexion another accessory 

Praying mantis 

• Specular Reflexion 


26

Praying Mantis Diffuse Reflectance Accessory 


27


• Diffuse Reflectance of powders and small 

samples 

• Beam image at sample position ~ 3 mm 

diameter 

• Optics are MgF 2 coated mirrors 

• Wavelength range ~ 190-1100 nm 

• Rejects specular component of reflection 

• Ideal for Inorganic chemists and solid state 

physics researchers 

• Works in Evolution 300 (190-1100 nm) and 

600 (190 – 900 nm) 


28


• Sample chamber can be purged with 

inert gas or dry air 

• Sleeves extend from the accessory and 

seal with sample compartment walls 

• Light sealed tube inserts in reference 

position 

• Accessory operates with sample 

compartment lid open (supply a magnet for 

Evolution 600 PMT cut-off) 

• Excellent for moisture or oxygen 

sensitive samples 


29


• Sample mounts in special cup inside the accessory 

• Small slices or flat faced chunks of sample can be laid 

on top of the large cup 

Large cup 

Depth = 0.125 inch = 3.2 mm 

Diameter = 0.42 inch = 10.5 mm 

Volume = 0.277 cm 3 

Extra/spare - PN 268-828200 $310 (2007) 

Small cup 

Depth = 0.125 inch = 3.2 mm 

Diameter = 0.125 inch = 3.2 mm 

Volume = 0.026 cm 3 

Extra/spare - PN 268-828300 $310 (2007) 


30

Temp. and Atmosphere Controlled Reaction Chambers 

• High Temperature Reaction Chamber 

• Operates from high vacuum (10 -6 torr) to 2-3 

atmospheres 

• Temperatures up to 600°C (under vacuum). 

• Can be adapted for high-pressure operation (up to 

500 psi) with a high-pressure dome assembly. 

• Low Temperature Reaction Chamber 

• Operates from high vacuum to 2-3 atmospheres 

and at temperatures from -150°C to 600°C (under 

vacuum). 

• Three inlet/outlet ports for evacuating the cell 

and introducing gases. 

• Made of chemically resistant 316 stainless 

steel. 

• Quartz windows for full range UV-Vis spectra 


31


• Customer Applications 

• Absorption edge calculations – find band gap in semiconductors 

• Studying Surface plasmon resonance – analytical tool in 

nano-science and trace gas/contaminant detector 

technology 

• In-situ catalysis studies 

• Measurements under controlled atmosphere 

• UV-Vis of molecules absorbed on a surface 

• Measurements at elevated or reduced temperature 

• Substituted/intercalated metals in minerals 


32

Band Gap in Semiconductors 

• Band Gap refers to the energy difference between two electronic 

levels in a material. 

• Valence Band 

• Lower energy level. Electrons are stuck on individual atoms. 

• Conduction Band. 

• Higher energy level. Electrons move around the material freely 

conduction band 

Energy 

band gap 

valence band 


33

Band Gap in Semiconductors 

• Metal 

• Band gap = zero 

• Conductor 

Energy 


valence band 

• Semiconductor 

• Small band gap 

• External influence such as applied 

voltage or photon of correct energy 

can promote electrons from valence 

to conduction band 

Energy 


Small band gap 

valence band 


• Insulator 

• Electrons cannot get into 


Energy 

Large band gap 

valence band 


34

It’s not just silicon wafers 

• Many materials are semiconductors 

• GaAs, InP, doped Si, GaInP 

• Organic molecules and films 

• Inorganic films 

• Doped inorganic compounds 

• Natural minerals (e.g. TiO 2 ) 

• Doped minerals 


35

Tauc Plot for Bandgap 

Science and Technology of Advanced Materials 6 (2005) 11–17, Sakae Tanemura, Lei Miaoa, Wilfried Wunderlich, Masaki 

Tanemura,Yukimasa Mori, Shoichi Toh, Kenji Kaneko 


36

Solid Sample Measurement -- Specular 

• Specular (mirror-like) Reflectance Accessories (SRAs) 

• VeeMAX SRA – variable angle 30° – 80° 

• Fixed angle SRAs (15°, 20°, 30°, 45°, 60°) 

• 8° and grazing angle (85°) on kinematic baseplate 


37

Specular Reflectance 

• Specular Reflectance is the 

reflectance from a “mirror-like” or 

glossy surface 

• Glossy paints have a higher 

proportion of specular reflection 

than matte paints 

• If you can see a “reflection” in it, it 

has significant specular reflectance 

• Specular reflectance 

measurements are performed on 

the Thermo VN Absolute Specular 

reflectance accessory (10 ° ) and 

Relative Specular reflectance 

accessories at 8 ° , 

15 ° ,20 ° ,30 ° ,45 ° ,60 ° & 85 ° angles of 

incidence 


Reflected angle = Incident angle 

38


Diffuse Reflectance 

Standards

Diffuse Color Standards from Labsphere 

• Spectralon diffuse color standards help manufacturers 

develop processes which can produce consistent color 

reproduction for products such as textiles, papers, 

pharmaceuticals, paints and inks 

• Diffuse color standards provide highly stable, 

reproducible spectral reflectance. 

• Spectralon color standards are durable and maintain a 

consistent reflectance over time. 

• Calibration data includes tristimulus values, 

chromaticity coordinates, UCS coordinates and 

CIELAB and CIELUV values. 

• The high thermal stability of Spectralon color standards 

eliminates the need to rigorously control the 

temperature in the laboratory. The slight color change 

of the standards with increasing temperature is 

extremely gradual and easily monitored. 

• Spectralon color standards are durable, washable and 

easily machined without loss of color or surface 

texture. The standards retain uniformity throughout, 

despite daily exposure to harsh environments 

• Diffuse Color Standards (Red-Green-Blue-Yellow) 


40

Diffuse Reflectance Standards 

• Spectralon white and grey 

standards are durable, 

washable and easily machined 

without loss of color or surface 

texture. The standards retain 

uniformity throughout, despite 

daily exposure to harsh 

environments 

• All Spectralon materials are 

typically flat to +/- 4% over the 

range of 250 - 900 nm+ 

• Diffuse Reflectance Standards 

(99%, 75%, 50%, 2%), 1 inch 

diameter 


41


Available Software 

Packages 

For 

Evolution 300 

and 

Evolution 600

VISION software options 

• VISIONpro 

• Full featured instrument control including PV tests, open beam 

scanning for accessory installation and alignment modes with white 

or green light. 

• PC control instruments ship with VISIONpro or VISIONsecurity - 

either will work to install or troubleshoot instrument and accessory. 

• VISIONlite MaterialsCalc 

• Simplified user interface compared to VISIONpro. 

• Includes macros for calculating materials science paramaters (e.g. 

Haze) 

• VISIONlite ColorCalc Basic / Advanced 

• Simplified user interface compared to VISIONpro. 

• Includes macros for calculating color coordinates according to 

various standards. 

• See product datasheets for full details 


43

Now switch on your mobile phones ! 

But switch off again during Tommasos 

speech 


44

Questions ?? 


45

Praying Mantis Diffuse Reflectance Accessory

Create successful ePaper yourself

Delete template?

Save as template?