[//en.wikipedia.org/wiki/Ultraviolet Wikipedia: Ultraviolet]
UV 400-10nm UV-A 400-315nm UV-B 315-280nm UV-C 280-100nm
The [//people.physics.anu.edu.au/~mxk121/research/absOzone.html UV absorption crosssection of O₃] ([//docs.google.com/a/graveslab.org/spreadsheet/ccc?key=0AuCoZGWGk5pvdE1UUTRDbmxCeGdDR1EyM29KcjdvN1E&usp=drive_web#gid=7 in a spreadsheet])
File:Ozone_crosssection.png|Ozone cross-section, generated from the above data
[//en.wikipedia.org/wiki/Mercury-vapor_lamp Wikipedia: Mercury Vapor Lamp]
The [//physics.nist.gov/PhysRefData/Handbook/Tables/mercurytable3.htm strongest peaks of the emission line spectrum] are:
| Wavelength (nm) | Color |
|---|---|
| 184.45 | ultraviolet (UVC) |
| 253.7 | ultraviolet (UVC) |
| 365.4 | ultraviolet (UVA) |
| 404.7 | violet |
| 435.8 | blue |
| 546.1 | green |
| 578.2 | yellow-orange |
In low-pressure mercury-vapor lamps only the lines at 184 nm and 253 nm are present. Only the light at 253 nm is usable. Synthetic quartz can be used in the manufacturing to keep the 184 nm light from being absorbed. In medium-pressure mercury-vapor lamps, the lines from 200–600 nm are present. The lamps can be constructed to emit primarily in the UV-A (around 400 nm) or UV-C (around 250 nm). High-pressure mercury-vapor lamps are those lamp commonly used for general lighting purposes. They emit primarily in the blue and green.
GravesLab has a [//www.uvp.com/penraylightsources.html UVP Pen-Ray] light source—this is a low-pressure mercury discharge lamp in a quartz envelope:
File:HG-Spektrum crop.jpg|Line spectrum of mercury vapor.
File:UVP_Hg_Spectrum.png|UVP low-pressure mercury discharge lamp spectrum.
[//en.wikipedia.org/wiki/Ultraviolet#Ultraviolet_LEDs Wikipedia: Ultraviolet LEDs]
LED efficiency at 365 nm is about 5–8%, whereas efficiency at 395 nm is closer to 20%, and power outputs at these longer UV wavelengths are also better.
[//www.intl-lighttech.com/products/light-sources/leds/uv-leds UV-A,B,C LEDs from International Light Technologies]
| Wavelength | Range | Output | Price |
|---|---|---|---|
| 265nm | UV-C | 0.5-1.0 mW | $456.20 |
| 280nm | UV-B | 1.0-1.5 mW | $390.36 |
| 310nm | UV-B | 1.0-1.5 mW | $392.18 |
| 365nm | UV-A | 3.0 mW | $15.75 |
| 395nm | UV-A | 3.0 mW | $3.45 |
GravesLab has a stock of Nichia NC4U133APE high-power UV-LED arrays:
ID 1244926
Type NC4U133APE
Date 2012.03.02
Rank UaP9d32b
This rank corresponds to: P9d32b 1660mW min; 1820mW max
Qty 3 pcs
engineering samples
runs at ~15.8V volts with a 1Ω series resistor
File:Nichia_NC4U133A_spectrum.png|emission spectrum
The hot filament of an incandescent bulb emits blackbody radiation according to Planck’s Law:
(B_{\lambda}(T) = \frac{2h c^{2}}{\lambda^5}\frac{1}{e^{\frac{hc}{\lambdak_{B}*T}}-1})
This can be plotted in [//sage.brandoncurtis.com/planck.html Sage Math].
[//docs.google.com/a/graveslab.org/spreadsheets/d/1NXqNWInyZMBdCjyQsTK3axbJBsMfMhtE_B1FK6iFToU/edit#gid=41474335 ASTM G173 Insolation Reference Spectra]
Solar Irradiance data: http://rredc.nrel.gov/solar/pubs/redbook/
http://rredc.nrel.gov/solar/spectra/
http://en.wikipedia.org/wiki/Sunlight
http://en.wikipedia.org/wiki/Ultraviolet
[//docs.google.com/a/graveslab.org/spreadsheet/ccc?key=0AlLciOIIcrN_dFRNNGVNUC1ELW81NHhJTEhKNXFuMXc#gid=0 Calculations on insolation, with/without atmospheric protection]
ETR = Extraterrestrial Radiation (solar spectrum at top of atmosphere) at mean Earth-Sun distance. Direct = Direct Normal Irradiance Nearly parallel (0.5 deg divergent cone) radiation on surface with surface normal tracking (pointing to) the sun, excluding scattered sky and reflected ground radiation
Circumsolar = Spectral irradiance within +/- 2.5 degree (5 degree diameter) field of view centered on the 0.5 deg diameter solar disk, but excluding the radiation from the disk
“Global Tilt” = spectral radiation from solar disk plus sky diffuse and diffuse reflected from ground on south facing surface tilted 37 deg from horizontal
