Difference between revisions of "Kuraray Fibre Tests"

From GlueXWiki
Jump to: navigation, search
 
Line 1: Line 1:
 
==Detector Setup==
 
==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 fibre is cut and polished on both ends with the [http://www.fiberfin.com/products/more/FF-FF4.htm 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 far end of the fibre is painted black with an enamel paint (used for painting scale models).
−
#The fibre is placed in a 4m long groove in a black poly-ethylene bar ("puck plastic")
+
#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 [ http://www.oceanoptics.com/products/fiberkits.asp#adapter bare-fibre SMA-connector] from Ocean Optics.
+
#The unpainted end is inserted into and held in place by a [http://www.oceanoptics.com/products/fiberkits.asp#adapter bare-fibre SMA-connector] from Ocean Optics.
 
#A UV LED (380nm) is used to illuminate the fibre from above
 
#A UV LED (380nm) is used to illuminate the fibre from above
 
#The spectra are obtained using an [http://www.oceanoptics.com/products/usb4000.asp Ocean Optics photo-spectrometer]
 
#The spectra are obtained using an [http://www.oceanoptics.com/products/usb4000.asp Ocean Optics photo-spectrometer]
 +
 +
  
 
== Fibre Spectra ==
 
== Fibre Spectra ==
Line 14: Line 16:
 
[[Image:K49-3-cl-blk-000.png |250px|"10cm"]][[Image:K49-3-cl-blk-009.png |250px|"100cm"]][[Image:K49-3-cl-blk-029.png |250px|"300cm"]]
 
[[Image:K49-3-cl-blk-000.png |250px|"10cm"]][[Image:K49-3-cl-blk-009.png |250px|"100cm"]][[Image:K49-3-cl-blk-029.png |250px|"300cm"]]
  
−
==Bi-Alkili Quantum efficiency approximation==
+
==Bi-Alkali Quantum efficiency approximation==
  
 
<math>I_{scaled} = I \times 0.25 exp{\left(\frac{1}{2}\frac{(\lambda-400nm)^{2}}{(80nm)^{2}}\right) } </math>
 
<math>I_{scaled} = I \times 0.25 exp{\left(\frac{1}{2}\frac{(\lambda-400nm)^{2}}{(80nm)^{2}}\right) } </math>
  
 
[[Image:Quantumefficiency.png|250px]]
 
[[Image:Quantumefficiency.png|250px]]
 +
 +
 +
==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:'''
 +
{| class="wikitable" style="text-align:center; border="1"
 +
!fibre # !! <math>\lambda</math> !! <math>d\lambda</math>
 +
|-
 +
! 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
 +
|}
 +
[[Image:Attenuation 6spectra.png|400px]]

Revision as of 20:20, 18 March 2009

Detector Setup

  1. 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)
  2. The far end of the fibre is painted black with an enamel paint (used for painting scale models).
  3. The fibre is placed in a 4m x 1mm groove in a black poly-ethylene bar ("puck plastic")
  4. The unpainted end is inserted into and held in place by a bare-fibre SMA-connector from Ocean Optics.
  5. A UV LED (380nm) is used to illuminate the fibre from above
  6. 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.

"10cm""100cm""300cm"

Bi-Alkali Quantum efficiency approximation

I_{{scaled}}=I\times 0.25exp{\left({\frac {1}{2}}{\frac {(\lambda -400nm)^{{2}}}{(80nm)^{{2}}}}\right)}

Quantumefficiency.png


Attenuation lengths

  1. 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 # \lambda d\lambda
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

Attenuation 6spectra.png

Retrieved from "https://halldweb.jlab.org/wiki/index.php?title=Kuraray_Fibre_Tests&oldid=12260"