Diffraction Spectrometry, Fall 2001

Group I

A study of Hydrogen, Helium, Nitrogen, Neon in excitation was conducted. This data was collected using a rotating arm spectrograph. The spectrograph data was drawn in the first node diffraction pattern from both the left and the right of the centerline of the grating. An average of the data was collected. The resulting angle was used to calculate the frequency of the escaping gamma.

Materials-

    1. Rotating arm spectrograph
    2. Excitation rig and voltage rheostat
    3. 600 mm-1 grating
    4. Gas element cathode tubes

Experimental errors- Experimental errors occurring during the data collection were as follows.

    1. Fluorescent light leaking into separation causing illumination and filling voided spectra.
    2. Although for each element one single observer was used. Separate observers were used for separate elements. Resulting in several observed spectra in disagreement.
    3. A level was not used to install the spectrograph resulting in the grating separation at an angle.
    4. Several spectra were blurry, toward the red-orange range in particular, making measurement estimations accuracy questionable.

Data-

Phys 3401 Lab

M. Cook & Jeff Stamper

Grating size(mm)

600

dSinf= ml

Visible Light ~ 420-670

Helium

 

Left

Right

mean

l (nm)

16.00

15.50

15.8

452

16.90

16.40

16.7

478

17.90

17.30

17.6

504

18.20

17.50

17.9

511

21.40

20.50

21.0

596

24.40

23.60

24.0

678

25.80

25.00

25.4

715

 

standard deviation

3.77

Mercury

Left

Right

mean

l (nm)

13.00

14.20

13.60

392

14.40

15.70

15.05

433

19.00

19.70

19.35

552

20.10

20.80

20.45

582

 

standard deviation

3.30

Neon

Left

Right

mean

l (nm)

18.00

20.00

19.0

543

19.80

21.90

20.9

593

22.40

23.30

22.9

647

23.50

24.10

23.8

673

 

standard deviation

2.14

Nitrogen

Left

Right

mean

l (nm)

14.50

15.50

15.0

431

18.90

20.00

19.5

555

19.90

21.50

20.7

589

22.00

23.90

23.0

650

 

standard deviation

3.35

hydrogen

left

right

mean

l (nm)

15.5

14.6

15.05

433

17.3

16.4

16.85

483

21

20.3

20.65

588

23.8

22.8

23.3

659

standard deviation

3.716




Mercury Spectrum

Helium Spectrum

Nitrogen (N2) Spectrum


Physics 3901