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-----
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## Introduction
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The requirement for XP applications is to measure very low levels of UV.
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Most of the sensors on the market are for high levels (for warning of
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getting a sunburn on normal skin), and so cannot be used.
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### Requirements
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- Resolution of 0.001 MED/hr or better
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-----
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## UV meter
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- [Solarmeter](http://www.solarmeter.com)
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- [Model 5.7 UV meter](http://www.solarmeter.com/model57.html)
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(demonstrated)
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- [Model 7.0 UV meter](http://www.solarmeter.com/model7.html)
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(MED/HR ERYTHEMALLY Effective (Eeff) UVR)
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- Resolution 1 µW/cm²
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- Irradiation range 0-1999 µW/cm² Total UV
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- <s>[Model 7.0 UV meter](http://www.solarmeter.com/model7.html)
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(MED/HR ERYTHEMALLY Effective (Eeff) UVR)</s>
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- The Model 7.0 has a resolution of 0.1 MED/hr whereas we need
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0.001 or preferably better.
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<!-- end list -->
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- Also available as the UV MINDER® Model 3D-XP Xeroderma Erythemal
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UV Intensity Meter for measuring very low UV intensity to 3
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decimal places
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- Readout range: 0...19.99 MED/Hr (standard model, the Xeroderma
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Erythemal UV Intensity Meter has one more decimal place).
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- *There is no datasheet of the Xeroderma Erythemal UV Intensity
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Meter model*
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- It is this model that is used as reference. It has only one
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detector, mounted in the middle of the device.
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*Note**
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- Arduino UV sensor have typically a resolution of 1 UV factor i.e. 1
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MED/hr, so cannot be used.
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-----
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## Units
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- Minimal Erythemal Doses per Hour (MED/Hr)
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- The shortest exposure to ultraviolet radiation that produces
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reddening of the skin within 1 to 6 hr and disappears in 24
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hr.
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The minimal erythemal dose is used to calculate the duration of
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therapeutic exposure to ultraviolet light. For treatment using a
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“hot” ultraviolet lamp (UV-A or UV-B), the dose is calculated at
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a distance of 30 in. The minimal erythemal dose for “cold”
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ultraviolet (UV-C) is standardized at 30 to 38 sec at a distance
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of 1 in. Synonym: erythema dose; threshold dose (from
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[thefreedictionary.com](http://medical-dictionary.thefreedictionary.com/minimum+erythema+dose)
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-----
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## Calibration methods
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- research needed
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- NIST standard (*reference needed*)
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- Relationship between µW/cm² and MED/hr (*reference needed*)
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-----
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... | ... | @@ -35,5 +77,5 @@ |
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-----
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18 November 2015
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19 November 2015
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