Lecture 7

Light sources, filters, and

monochromators

Harris Ch.20

Light Source

Sample

Monochromator(filter,

wavelength selector)

Detector

SpectrometerData Processing

Black body radiation

A tungsten lamp

3000 K

Deuterium Lamp

hHHHEH '''202

Deuterium: higher intensity

Even higher intensity: Xe arc

UV sources

Light Source

Sample

Monochromator(filter,

wavelength selector)

Detector

SpectrometerData Processing

Filters

nl 2maxthickness

Refractive index

A Bunsen monochromator

Detector plate

Refractive index of NaCl350 nm 1.58460 nm 1.56 680 nm 1.54 1250 nm 1.53

7.30m 1.51 10.6m 1.49 12.0m 1.48 13.1m 1.47 14.2m 1.46 15.1m 1.45 16.0m 1.44

Quarz prisms

LittrowCornu

Czerney-Turner monochromator

)sin(sin dn

nN

Diffraction order

Number of grooves

cosd

n

d

d

Dispersion:Resolution (resolving power):