UV Basics:
Calculating
Dose/Fluence
Terminology
•
•
•
•
•
Dose vs Fluence?????
UV Transmission (UVT, UVT254 , UVT200)
Biodosimetry
Reduction Equivalent Fluence/Dose
Validated Fluence/Dose
Dose vs Fluence?????
IUPAC Gold book Definitions:
Dose
“Energy or amount of photons absorbed per volume (or per
mass) by an irradiated object during a particular exposure
time.”
Fluence
“At a given point in space, the radiant energy incident on a
small sphere divided by the cross-sectional area of that
sphere”.
UV Transmission
10mm
Blank (DI Water)
Eo
Et
UVTλ = …%
UV Transmission
LAMP
UV Transmission
LAMP
80%
UV Transmission
LAMP
80%
64%
UV Transmission
LAMP
80%
64%
51%
UV Transmission
LAMP
80%
64%
51%
41%
UV Transmission
LAMP
80%
64%
51%
41%
Practical Calculation of UV Fluence
(Quasi) Collimated Beam
Lamp
Radiometer
Petri Dish
Low Pressure (LP) Calculation
Incident Energy
(Fluence Rate)
X
Sample Transmission
X
Time
= UV FLUENCE
Medium Pressure Collimated Beam
Methodology
Lamp Emission Spectrum
Action Spectrum
1.6
Absorbtion cm-1
1.4
1.2
1
0.8
0.6
0.4
0.2
0
200
210
220
230
240
250
260
270
280
290
300
Wavelength (nm)
Action Spectra (DNA abs)
Detector Sensitivity
Spectral Transmission
14
10
8
6
4
2
0
200
220
240
260
Wavelength (nm)
280
300
320
Percentage Transmission
Relative Sensitivity
12
100
90
80
70
60
50
40
30
20
10
0
200
210
220
230
240
250
260
270
280
290
300
Polychromatic (Medium Pressure)
Collimated Beam Calculation
Incident Energy (λ) x
Action Spectrum (λ)
X
Matrix Transmission (λ)
X
Time
Polychromatic Calculation to 253.7nm
Log Inactivation
MP
LP
Fluence
Practical Surrogate Example
T1UV Phage
HER 1024
E.coli Host
ATCC 11303
E.coli Host
ATCC 700609
"Phage" by Dr Graham Beards - en:Image:Phage.jpg. Licensed under Public domain via Wikimedia Commons -
Reactor Fluence/Dose Calculation
(Biodosimetry)
Reduction Equivalent Fluence / Dose
Collimated Beam
Surrogate
Reduction
UV Reactor
Reduction
Equivalent Fluence
Practical Considerations
(Plate Counts)
Practical Considerations
(Plate Counts)
20-200 pfu
Practical Considerations
(Dilution Series)
1/10
1/10
1/10
1/10
Validated Fluence/Dose
Validated Fluence/Dose
Validation Uncertainty
“an uncertainty term that accounts for error in
measurements made during validation testing to develop
the UV intensity setpoint(s) (for the UV Intensity Setpoint
Approach) or dose-monitoring equation (for the
Calculated Dose Approach).” (UVDGM 2006)
Validated Fluence/Dose
Validation Uncertainty
“an uncertainty term that accounts for error in
measurements made during validation testing to develop
the UV intensity setpoint(s) (for the UV Intensity Setpoint
Approach) or dose-monitoring equation (for the
Calculated Dose Approach).” (UVDGM 2006)
REF x Validation Factor = Validated Dose
(Safety/Uncertainty)