12. UV Radiation Sources - fh-muenster.de...Chapter UV Radiation Sources Slide 9 Incoherent light...

Chapter UV Radiation Sources

Slide 1

Incoherent light sources

Prof. Dr. T. Jüstel, FH Münster

12. UV Radiation Sources

Content

12.1 Classification of UV Radiation

12.2 Photochemical Applications

12.3 Biochemical Applications

12.4 UV Radiation Sources

12.5 Artificial UV Radiation Sources

12.6 UV-Phosphors

12.7 Tanning Lamps

12.8 Psoriasis Lamps

12.9 Radiation Sources for Disinfection Purposes

12.10 Radiation Sources for Water Purification Purposes


Slide 2



100 nm 200 nm 280 nm 320 nm 400 nm

UV-B UV-A UV-C VUV

12.5 - 6.9 eV 6.2 – 4.5 eV 4.5 - 3.9 eV 3.9 – 3.1 eV

Decomposition of H2O

and O2 to radicals

Ozone formation

Cleavage of C-C, C-H,

C-O bonds

Excitation of C=C

bonds

Excitation of the

nucleobases

Decomposition of O3,

ClO2 and H2O2

Vitamin D formation

Transcription of repair

enzymes

Formation of

melanosomes in the skin

Photocatalytic reactions

Oxidation of melanin in

the skin

Decomposition of

organic pigments

Activation of

photocatalytic pigments

Wafer cleaning

Photochemistry

Disinfection of air, H2O

and surface

Photochemistry

Treatment of skin

diseases (psoriasis)

Tanning

Photochemistry

Water and air

purification using TiO2

photocatalyst

Tanning

Photochemistry

12.1 Classification of UV Radiation


Slide 3



Chemical Bonds and Photon Energy

Energy of chemical bonds

~ 10 – 1000 kJ/mol

Energy of optical radiation

E = NAhc/ = 119226/ [kJmol-1]

600

300

150

200 400 800

Ultraviolet Visible Near Infrared

Thus (V)UV to VIS radiation is able to cleave covalent chemical bonds

E-E 100 – 500 kJ/mol F-F 159 kJ/mol

C-C 348 kJ/mol

E=E 400 – 700 kJ/mol O=O 498 kJ/mol

C=C 648 kJ/mol

EE 800 – 1100 kJ/mol NN 946 kJ/mol

CC 839 kJ/mol

H-bridges 10 - 160 kJ/mol H...F > H...O > H...N

Van-der-Waals 0.5 - 5 kJ/mol

1200 kJ/mol-1

Vacuum Ultraviolet

100 nm

75

1600



Slide 4



]


Ozone layer

Va

cuu

m

UV

UV

-

C

UV

-B (

28

0 –

30

0

nm

)

UV

-A &

UV

-B (

30

0 –

32

0 n

m)

1.37 kW/m2

Penetration depth and impact

of UV Radiation (100 - 380 nm)

Vacuum UV (100 - 200 nm)

• Photolysis of water

• Cleavage of N2 and O2

• Ozone formation

UV-C (200 - 280 nm) &

UV-B (280 - 300 nm)

• Ozone cleavage

UV-B (300 - 320 nm) &

UV-A (320 - 380 nm)

• Photochemical degradation

of air pollutants

• Disinfection at photo-

catalytically active sites


Slide 5



Photolysis reaction (selection)

• Decomposition of azides

M-N=N=N + h(< 300 nm) M=N + N2 with M = Cr, Mn, Fe, Ru and so on

• Homolytic decomposition of iodine

I2 + h(520 nm) 2 I.

• Decomposition of HgO

2 HgO + h(< 600 nm) 2 Hg + O2

• Decomposition of diazo-compounds

R-CO-CH=N=N + h(< 350 nm) R-CH=C=O + N2

• Isomerization reactions

praecalciferol + h(282 nm) calciferol (vitamin D3)

• Decomposition of formic acid HCOOH

HCOOH + h(< 260 nm) CO + H2O



Slide 6




Synthesis of organic compounds

• Photoinitiated polymerisation

K[Cr(NH3)2(NCS)4] + 2 H2O + h K[Cr(NH3)2(NCS)3(OH)] + H3O+ + NCS-

Anionic polymerisation of ethyl--cyanoacrylate by addition of NCS- as a chain starter

• Photooxidative initiated polymerisation

Flow coat process as a step of the CRT production process

(polyvinyl alcohole + ammonium dichromate)

R-CH2-OH + CrO42- + h(vis.) R-CH=O Polymerisation

• Photooxidative synthesis of organic molecules


Slide 7




Water and surface cleaning with VUV radiation

1. Decomposition of water to radicals

H2O + h(< 200 nm) OH. + H.

2 OH. H2O2

2 H2O2 2 H2O +1O2

2. Ozone formation

3 O2 + h(< 240 nm) 2 O3

H2O2 and O3 decompose organic substances by oxidation


Slide 9




Disinfection

Water, air and surface contain microorganisms such as fungi, bacteria, protozoa and viruses

Killing of microorganisms by

• Heat (> 80 – 120 °C)

• Chemicals (Cl2, ClO2, O3)

• UV radiation (< 300 nm)

The effect of UV radiation is mainly

due to the inhibition of the growth

of microorganisms

220 240 260 280 300 320 340 360 380 4000,0

0,2

0,4

0,6

0,8

1,0Disinfection efficiency (DIn 5031-10)

Absorption spectrum of dTMP

Re

l. e

ffic

ien

cy/a

bso

rptio

n

Wavelength [nm]


Slide 10




Disinfection - Photo biochemistry

Structure of DNA

• helical double strand of nucleotides dNMP

• dNMP = base + phosphate + desoxyribose

-A-T-A-T-G-C-T-A-G-G-C-C-

-T-A-T-A-C-G-A-T-C-C-G-G-

Mechanism of disinfection

UV-C is absorbed by purine and pyrimidine bases

Reaction between adjacent thymine bases

(2 + 2 cycloaddition, according to Woodward-Hoffmann)

Failed to copy DNA

Nucleotide Extinction coefficient at 260 nm

dAMP 15200

dTMP 8400

dGMP 12000

dCMP 7100

P

P

O

CCCN

NCO

O

CH3H

H

P

O

CCCN

NCO

O

CH3H

H

O

CC

CNNC O

O

CH3

H

HO

OCC

CNNC

O

CH3H

H

P


Slide 11




Direct pigmentation: Oxidation of melanin to melanin oxide (short term effect and lifetime)

Indirect pigmentation: Incorporation of new melanosomes (long-term effect)

250 300 350 400 450 500

0,0

0,2

0,4

0,6

0,8

1,0

0,0

0,2

0,4

0,6

0,8

1,0 Direct pigmentation

Indirect pigmentation

Wavelength [nm]

Re

lative

effe

ctive

ne

ss [a

.u.]

Tanning

UV-A: Direct pigmentation

UV-B: Indirect pigmentation

Tanning of the skin

Ref

lect

ion

400 500 600 700 800

50%

40%

30%

20%

10%

0%

Increase in

absorption

Wavelength [nm]


Slide 12



By UV radiation, the skin is irritated and as a result of increased blood flow reddened

Prolonged UV exposure leads to phototoxic reaction (sunburn)

Skin sensitivity according to

DIN 5031-10

250 - 298 nm: E = 1

298 - 328 nm: E = 1*10^(0.094*(298-))

328 - 400 nm: E = 1*10^(0.015*(140-))

260 280 300 320 340 360 380 400 420

1E-3

0,01

0,1

1

Re

lati

ve s

pe

ctr

al

eff

icie

nc

y

Wavelength [nm]


Tanning - Side effect: Erythema = skin redness or sunburn


Slide 13




280 300 320 340 360 380 4000,0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

0,9

1,0

1,1

Vitamin D3 production

Rela

tive e

ffectiven

ess

Wavelength [nm]

280 300 320 340 360 380 4000,0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

0,9

1,0

1,1

Photoconjunctivitis

Pyrimidine dimerisation

Photoceratitis

Re

lative

effe

ctive

ne

ss

Wavelength [nm]

Vitamin D3 Production in the skin Phototoxic effects

Tanning - Other side effects

• UV-B radiation is mainly responsible for positive and negative effects

• The wavelength dependency of biological effects is very distinct in the UV-B


Slide 14




Overview Solar radiation > 300 nm Hg discharge lamps low-pressure 185, 254 nm amalgam 185, 254 nm medium-pressure 200 – 400 nm Xe discharge lamps 230 – 800 nm D2 discharge lamps 110 – 400 nm Excimer laser 193 nm Solid state laser Nd3+ 4th harmon. 266 nm Excimer discharge lamps Xe2* 172 nm KrCl* 222 nm XeBr* 282 nm XeCl* 308 nm (Al,Ga)N LEDs 210 – 365 nm (In,Ga)N LEDs 365 – 400 nm


Slide 15




Solar Radiation

~ 5% UV ~ 60% VIS ~ 35% IR

The solar spectrum depends on daytime & season,

air pressure, clouds, particles (dust) and so on

AM

0

AM

1.0

Earth„s surface

< 400 400 - 500 500 - 600 600 - 700 > 700

37.8 W/m² 130.4 W/m² 144.6 W/m² 134.0 W/m² 269.2 W/m²

5.3% 18.2% 20.2% 18.7% 37.6%

48.2°

0,0

0,2

0,4

0,6

0,8

1,0

500 1000 1500 2000 2500 3000 3500 4000

Black Body (T = 5800 K)

0,0

0,2

0,4

0,6

0,8

AM0 (extraterrestric)

No

rmalised

em

issio

n in

ten

sit

y [

a.u

.]

500 1000 1500 2000 2500 3000 3500 4000

0,0

0,2

0,4

0,6

0,8 AM1.5 (48.2 ° angle)

Wavelength [nm]

O2

O3

H2O

CO2

CO2


Slide 16




Skin redness or sunburn are mainly

caused by UV-B radiation

280 300 320 340 360 380 4000,0

0,2

0,4

0,6

0,8

1,0

1,2

L [

Wm

-2nm

-1]

Wavelength [nm]

280 300 320 340 360 380 4000,000

0,002

0,004

0,006

0,008

0,010

Le

r [W

nm

-1m

-2]

Wavelength [nm]

Solar UV Radiation

UV spectrum at 60° solar elevation angle Analogous erythema spectrum

400

280

totr, )dλ)E(L(L e


Slide 17




Time dependent distribution of solar UV radiation (Norderney: 53.2° north latitude)

Season

Day

tim

e


Slide 18




Local distribution of UV radiation (on 21st June at high noon)

At high latitudes is very little UV-B radiation in solar light

Hamburg (~53.5° north latitude) on 21st June, at midday (solar elevation angle ~ 60°)

• UV-B/UV-A [%] 2.30

• E(<320)/E(>320) 3.54

Solarheight

Latitude[°] N

Nearest location at10° E

UV-B[W/m2]

UV-A[W/m2]

UV-B[%]

E<320

[W/m2]E>320

[W/m2]E<320/E>

320

83.5 30 Ghadames, Libya 1.66 61.0 2.65 0.1654 0.0380 4.35

78.5 35 Sfax, Tunisia 1.61 59.9 2.61 0.1587 0.0373 4.25

73.5 40 Sardinia 1.52 58.0 2.55 0.1487 0.0360 4.13

68.5 45 La Spezia, Italy 1.41 55.7 2.47 0.1359 0.0345 3.94

63.5 50 Schweinfurt, Germany 1.28 52.7 2.37 0.1208 0.0325 3.72

60 53.5 Hamburg, Germany 1.18 50.2 2.30 0.1094 0.0309 3.54

58.5 55 Århus, Denmark 1.13 49.1 2.25 0.1043 0.0302 3.45

53.5 60 Oslo, Norway 0.97 45.0 2.11 0.0870 0.0275 3.16

48.5 65 Trondheim, Norway 0.80 40.5 1.94 0.0697 0.0246 2.83


Slide 19



Lamp types

Hg discharge lamps

• Low-pressure 185, 254 nm

• Medium pressure + filter 200 - 400 nm

• Low-pressure + phosphor 200 - 400 nm

Excimer lamps

• Xe2* 172 nm

• KrCl* 222 nm

• XeBr* 282 nm

• XeCl* 308 nm

• Xe2* + phosphor 190 - 400 nm

LEDs and laser diodes

• (Al,Ga)N LEDs 210 – 365 nm • (In,Ga)N LEDs 365 – 400 nm

“UV-C Radiation source”



Slide 20



Emission maxima and efficiencies of excimer light sources in the sinus operation


F Cl Br I Noble gas

Pure halogen

? 158 nm

? 258 nm

? 293 nm

? 342 nm -

Ar > 10% 193 nm

ca. 5% 175 nm

< 0.1% 161 nm

- Ar*

2

~10% 126 nm

Kr > 10% 248 nm

18% 222 nm

ca. 5% 207 nm

< 0.1% 185 nm

Kr* 2

~15% 146 nm

Xe > 10% 351 nm

14% 308 nm

15% 282 nm

ca. 5% 253 nm

Xe* 2

30% 172 nm


Slide 21




Medium pressure mercury lamps

• Lamp glass and filter: No emission below 280 nm!

• High UV-B percentage ~ 10% Face tanner

200 250 300 350 400 450 500 550 600 650 700 750 8000

10

20

30

40

50

60

70

80

90

100

110

120

HPA404

HPA1200

Em

iss

ion

in

ten

sit

y (

a.u

.)

Wavelength [nm]


Slide 22



Fluorescent lamps Low-pressure mercury discharge

Xe2*-excimer discharge

200 300 400 500 6000,0

0,2

0,4

0,6

0,8

1,0

185 nm

254 nm

No

rma

lize

d e

mis

sio

n in

ten

sity

Wavelength [nm]

150 nm

172 nm

UV radiation

UV emitting

phosphor layer

Wavelength [nm]

147 nm 172 nm

Re

so

na

nzlin

ie

Em

issi

on

in

ten

sity

2 n

d K

on

tinu

um

1 s

t Ko

ntin

uu

m

185 nm

254 nm

Lamp glass

German patent

DE 199 19 169.7

150 nm



Slide 23



Commercial phosphors for UV light sources on

the basis of a low-pressure mercury discharge

SrAl12O19:Ce3+ 305 nm

LaB3O6:Bi3+,Gd3+ 311 nm

LaPO4:Ce3+ 320 nm

LaMgAl11O19:Ce3+ 340 nm

(Y,Gd)PO4:Ce3+ 335, 355 nm

BaSi2O5:Pb2+ 350 nm

Sr2MgSi2O7:Pb2+ 365 nm

SrB4O7:Eu2+ 370 nm

BaSO4:Eu2+ 375 nm

Activators: Ce3+, Gd3+, Pb2+, Eu2+

280 300 320 340 360 380 400 420 440 460

0,0

0,2

0,4

0,6

0,8

1,0

BaSO4:Eu

YPO4:Ce

LaMgAl11

O19

:Ce

Em

issi

on in

tensi

ty [

a.u

.]

BaSi2O

5:Pb SrB

4O

7:Eu

Sr2MgSi

2O

7:Pb

Wavelength [nm]

280 300 320 340 360 380 400 420 440 460

0,0

0,2

0,4

0,6

0,8

1,0LaB

3O

6:Bi,Gd

Em

issi

on

inte

nsi

ty [

a.u

.]

LaPO4:Ce

SrAl12

O19

:Ce

Wavelength [nm]

12.6 UV-Phosphors


Slide 24



UV and VUV efficiency of UV-A phosphors (Ce3+ and Pb2+ activated)

254 nm efficiency : LaMgAl11O19:Ce ~ YPO4:Ce ~ BaSi2O5:Pb ~ Sr2MgSi2O7:Pb

172 nm efficiency : LaMgAl11O19:Ce > YPO4:Ce ~ BaSi2O5:Pb > Sr2MgSi2O7:Pb

150 200 250 300 3500,0

0,2

0,4

0,6

0,8

1,0YPO

4:CeLaMgAl

11O

19:CeBaSi

2O

5:Pb

Sr2MgSi

2O

7:Pb

Rela

tive

inte

nsi

ty

Wavelength [nm]

172 nm

12.6 UV-Phosphors


Slide 25



Historical development • 60s and early 70ties Hard UV radiation sources (UV-C!) "sunlamps"

• the mid 70ties Hard UV radiation damages the DNA TL lamps with UV-A fluorescent • late 70ties TL lamps with enhanced UV-A fluorescent

• 80ties Tanning with UV-A radiation is safe TL lamps with UV-fluorescent compounds High-pressure mercury lamp with filter

• early 90ties UV-B/UV-A balanced ratio is favorable Lamps with glass with high UV transparency (and

UV-B fluorescent) • late 90ties Optimal are radiation sources with daylight

UV- spectrum UV-B/UV-A phosphor mixtures • Since ~ 2000 Mainly UV-A phosphors

12.7 Tanning Lamps


Slide 26



Fluorescent lamps - Historical development

1. Generation 2. Generation 3. Generation

BaSi2O5:Pb BaSi2O5:Pb YPO4:Ce

or Sr2MgSi2O7:Pb + LaPO4:Ce + LaPO4:Ce

The stability of Pb2+ phosphors limits the lifetime of tanning lamps to about 1000 h

280 300 320 340 360 380 400

0,0

0,2

0,4

0,6

0,8

1,0

LaPO4:Ce

BaSi2O

5:Pb

UV-AUV-B

Em

issi

on in

tensi

ty [

a.u

.]

Wavelength[nm]

280 300 320 340 360 380 400

0,0

0,2

0,4

0,6

0,8

1,0

BaSi2O

5:Pb

UV-AUV-B

Em

issi

on inte

nsi

ty [

a.u

.]

Wavelength[nm]

280 300 320 340 360 380 400

0,0

0,2

0,4

0,6

0,8

1,0

LaPO4:Ce

YPO4:Ce

UV-AUV-B

Em

issi

on in

tensi

ty [

a.u

.]

Wavelength[nm]

12.7 Tanning Lamps


Slide 27



Due to the presence of Hg lines in the visible spectral

range tanning lamps emit blue light

Conversion into a white light spectrum by adding a red-

emitting phosphor, such as Y2O3:Eu

200 300 400 500 6000,0

0,3

0,5

0,8

1,0

Re

lativ

e In

ten

sitä

t

Wellenlänge [nm]

12.7 Bräungungslampen 12.7 Tanning Lamps

Fluorescent lamps – Spectra & color point

0,0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,80,0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

0,9

Y2O

3:Eu

CLEO Performance

BBL

y

x


Slide 28



12.7 Tanning Lamps

Fluorescent light sources with daylight erythema spectrum

UV-A + UV-B phosphor, e.g. LaPO4:Ce + BaSi2O5:Pb

280 300 320 340 360 380 4000,0

0,2

0,4

0,6

0,8

1,0

CLEO Natural

Referenz-Sonnenlicht

UV-AUV-B

Re

lative

Brä

un

un

gse

ffiz

ien

z

Wellenlänge [nm]


Slide 29




Treatment of skin diseases

Psoriasis, vitiligo, atopic dermatitis and other skin diseases can be treated with UV-B

radiation

Psoriasis lamps

Low-pressure mercury lamps

+ UV-B phosphor

Standard phosphor

LaB3O6:Bi3+,Gd3+

UV-B line emitter!

Excitation Bi3+ (Bi3+)*

Energy transfer (Bi3+)* + Gd3+ Bi3+ + (Gd3+)*

Emission (Gd3+)* Gd3+ + 311 nm (6P7/2 8S)

Emission spectrum of LaB3O6:Bi,Gd

(254 nm excitation)

200 300 400 5000,0

0,2

0,4

0,6

0,8

1,0

Em

issio

n in

ten

sity [a

.u.]

Wavelength [nm]


Slide 30



Phosphors for UV-B fluorescent lamps

Standard LaB3O6:Bi3+,Gd3+ New materials with Gd3+ as an emitter

Sensitization is required Ce3+ or Pr3+

Problem: Photostability of Bi3+

Solution: Use Ce3+ as a photosensitizer

Small splitting of the 5d-orbitals of Ce3+ is required (e.g. in phosphates)

Host lattices with high coordination number of trivalent lanthanide ions

100 150 200 250 300 350 400 450 5000,0

0,2

0,4

0,6

0,8

1,0

Ce3+

(5d1- 4f

1)

Ce3+

(4f1 - 5d

1)

Host lattice

Gd3+

(6P

J -

8S)

Emission spectrum 254 nm exc.

Excitation spectrum

Re

lative

in

ten

sity

Wavelength [nm]

100 200 300 400 5000,0

0,2

0,4

0,6

0,8

1,0

Bi3+

Bi3+

Bi3+

Host lattice

Gd3+

(6P

J -

8S)

Emission spectrum 254 nm exc.

Excitation spectrum

Re

lative

in

ten

sity

Wavelength [nm]



Slide 31



To disinfect water, air and surface

Requirements

• Emission between 230 and 280 nm

• No radiation < 230 nm, otherwise photoreduction of NO3- to NO2

- (in water)

• No radiation < 200 nm, otherwise photoreduction of H2O into H. + OH.

Suitable lamp types

• Hg-low pressure discharge lamps

Line emission at 254 nm

• Hg-medium pressure discharge lamps

Emission in the entire UV range

• Hg-high pressure discharge lamps

Emission in the entire UV range 200 300 400 500 600

0,0

0,2

0,4

0,6

0,8

1,0

254 nm

Em

issio

n in

ten

sity

Wavelength [nm]

Spectrum of a Hg-low pressure discharge lamps



Slide 32



Mercury Low Pressure Discharge Efficiency

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50 60 70 80

Temperature / °C

Rel

ati

ve

Eff

icie

ncy

/ %

Pure Mercury

BiIn Amalgam


Hg-discharge lamps: Disadvantages

• Environmental compatibility (Hg content)

• Sensitivity to fast switching cycles

• Temperature dependence of the discharge efficiency and UV light output

(water temperature ~ 10 – 15 °C)

• Cylindrical geometry


Slide 33



+

-

Arc discharge

Electrode (cathode)

Dielectric

Phosphor layer

e- + Xe Xe*

Xe* + 2 Xe Xe2* + Xe

Xe2* 2 Xe + 172 nm

AC


Dielectric barrier discharge lamps (Xe excimer lamps)

Phosphor layer

Dielectric

Electrode (anode)


Slide 34



Wavelength [nm] 147 172

Res

on

an

ce L

ine

Inte

nsi

ty [

a.u

.]

2 n

d C

on

tin

uu

m

1 st

Co

nti

nu

um


Xe2* excimer discharge

emission spectrum

convert to 190 - 200 nm convert to 200 - 280 nm

10 0

10 1

10 2

10 3

10 4

10 5

10 6

10 7

10 8

H2O

Ab

sorp

tion

coef

fici

ent

[m-1

]

10 0

10 -1

10 -2

10 -3

10 -4

10 -5

10 -6

10 -7

10 -8

Pen

etra

tio

n d

epth

[m

]

150 160 170 180 190 200

Xenon excimer

Wavelength [nm]

200 220 240 260 280 300 320 0.0

0.2

0.4

0.6

0.8

1.0

Disinfection efficiency (DIN 5031-10)

Rel

. ef

fici

ency

/ab

sorp

tion

Wavelength [nm]

To increase the penetration depth To increase the "GAC-overlap"

Xe excimer lamps


Slide 35



UV-C phosphors for Xe excimer lamps

Requirements

• Emission band in the region (190) 200 - 280 nm

• High light output under 172 nm excitation

• VUV high stability

Host lattice with wide band gap > 6.0 eV and redox-stable activators

Phosphor = host lattice + activator optical transition

Fluoride Tl+ 6s-6p

Phosphate Pb2+ 6s-6p

Sulfate Bi3+ 6s-6p

Borat Nd3+ 4f-5d

Oxide Pr3+ 4f-5d



Slide 36



Free ion

in the

gas phase

Activator

host lattice

interaction

Crystal field

splitting

Free Ion Eu2+ Ce3+ Pr3+ Nd3+ Gd3+

4fn-15d1 34000 cm-1 49340 cm-1 61580 cm-1 72100 cm-1 95200 cm-1

295 nm 203 nm 162 nm 139 nm 105 nm

E 5d

4f

c

cfs

Stokes shift


UV-C phosphors - Tuning of the activator absorption and emission spectra


Slide 37



Nd3+ phosphors VUV radiation sources

Pr3+ phosphors UV-C radiation sources

200 250 300 350 4000,0

0,2

0,4

0,6

0,8

1,0

YPO4:Pr

YBO3:Pr

LaPO4:Pr

Em

issi

on

inte

nsi

ty [

a.u

.]

Wavelength [nm]

200 250 300 350 4000,0

0,2

0,4

0,6

0,8

1,0

Em

issi

on

inte

nsi

ty [

a.u

.]

Wavelength [nm]

YPO4:Nd


Nd3+ and Pr3+ phosphors

[Xe]4f25d1 [Xe]4f3 (4IJ) [Xe]4f15d1 [Xe]4f2 (4HJ, 3F2)


Slide 38



Spectrum of a Xe excimer lamp with YBO3:Pr as VUV to UV-C converter

0

100

200

300

400

500

600

200 250 300 350 400 450 500 550 600

Wavelength [nm]

Inte

nsi

ty[

10

3 C

ou

nts

/s]

0

10

20

30

40

50

60

70

80

90

100

Rel

ati

ve

ger

m k

illi

ng

eff

ect

[ %

]

Lamp spectrum

DIN – Response spectrum


12. UV Radiation Sources - fh-muenster.de...Chapter UV Radiation Sources Slide 9 Incoherent light...

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Transcript of 12. UV Radiation Sources - fh-muenster.de...Chapter UV Radiation Sources Slide 9 Incoherent light...