sphenix-hcal-l AT lists.bnl.gov
Subject: sPHENIX HCal discussion
List archive
[Sphenix-hcal-l] Reply from Kuraray re question about Y-11 fiber emission
- From: Sean Stoll <stoll AT bnl.gov>
- To: sphenix-hcal-l AT lists.bnl.gov
- Subject: [Sphenix-hcal-l] Reply from Kuraray re question about Y-11 fiber emission
- Date: Tue, 21 Aug 2018 10:48:05 -0400
|
From: Shinji, Osamu_新治修
Dear Sean Stoll - san,
I am one of technical of KURARAY scintillating fiber. I am trying to answer to your question.....Y-11(200) 1mm fiber is doped with a high concentration of so called K-27 fluorescent dye, 200ppm. Because the 1mm fiber can absorb a blue light efficiently more than 90%, when emitted blue lights from a scintillator go across the WLS fiber of 1mm diameter (refer to the attached file). On the other hand, “Absorption and Emission Spectra” on our web site was measured with a very diluted solution, eg. a few 10s ppm, using 10mm * 10mm quarts cell described in the attached file. The reason why we used a very diluted solution is to measure the intrinsic and real emission spectrum without no self - absorption. You can see the “Absorption and Emission Spectrum” of Y-11 has an absorption – emission overlap between around 450-480nm wavelength. These wavelengths are, as we call, the range of self –absorption. If we used a solution of higher concentration, eg. 200ppm using the using 10mm * 10mm cell, we would get a very different emission spectrum from the intrinsic and real, which spectrum would be lost with the peak emission at 476nm because of the self - absorption.
About Y-11(200) fiber doped with 200ppm, that is the reason why the peak emission at 476 disappeared at the 1m end of fiber, as you observed. Using this fiber, this 476nm peak will disappear at only 1-10cm from the point of illuminated with a blue light. You can see that this peak already disappears at 10cm “Emission Spectra” on our web site.
The second reason why the emission spectrum changes at different length, like “Emission Spectra” on the Y-11(200) fiber, is due to transmission loss of polystyrene fiber. The figure of “Transmission Loss” of Y-11(200) fiber on the same page shows that the loss is higher at a shorter wavelength with a steeply dipping curve between 500nm and 600nm. The trans mission loss L(dB/Km) can be calculated to transparency T(%) at X(m) by the equation T= 10^(-LX/10000)*100. So shorter components of the intrinsic spectrum are lost more rapidly, surviving those of longer wavelengths. Because the emission spectrum at the fiber end is a ‘survived’ spectrum from the intrinsic emission passing through a long fiber with different transparency every wavelength, the ‘apparent peak wavelength’ observed from the end of a longer fiber will goes longer.
Can I answer to your question well? If any more or other technical questions or requests, please let us know directly. The last two CC addresses of this e-mail are of the other technical persons of KURARAY scintillation fiber.
Thank you very much,
Osamu Shinji KURARAY 差出人： "Cuevas, Sean" <Sean.Cuevas AT kuraray.com>
|
Attachment:
Absorption&Emission of Y7811.pdf
Description: Adobe PDF document
- [Sphenix-hcal-l] Reply from Kuraray re question about Y-11 fiber emission, Sean Stoll, 08/21/2018
Archive powered by MHonArc 2.6.24.