Kuraray Fibre Tests
From GlueXWiki
Contents
Detector Setup
- The fibre is cut and polished on both ends with the Fiber Fin polisher (the label must be removed due to it's placement too close to the end)
- The far end of the fibre is painted black with an enamel paint (used for painting scale models).
- The fibre is placed in a 4m x 1mm groove in a black poly-ethylene bar ("puck plastic")
- The unpainted end is inserted into and held in place by a bare-fibre SMA-connector from Ocean Optics.
- A UV LED (380nm) is used to illuminate the fibre from above
- The spectra are obtained using an Ocean Optics photo-spectrometer
Fibre Spectra
Typical fibre spectra at 10,100 and 300 cm.The green data points are the raw spectra as seen by the photo-spectrometer. The light blue points are scaled by an approximation to the quantum efficiency of a Bi-Alkali photocathode.
Bi-Alkali Quantum efficiency approximation
Attenuation lengths
- The attenuation length is found by taking the integral of the fit function of the scaled spectra and fitting that as a function of distance from the spectrometer. The fit function is a single exponential: I = A * exp(-x/B). The attenuation length is then effectively that of the fibre as seen by a PMT.
So far 6 fibers have had their attenuation lengths measured:
Attenuation length:
fibre # | ||
---|---|---|
01-3 | 440 | 12 |
23-2 | 443 | 10 |
26-2 | 478 | 10 |
32-2 | 414 | 30 |
33-2 | 398 | 15 |
49-3 | 441 | 12 |
Avg | 436 | 15 |