CMS Forward Calorimeter Fiber Specifications

3. 1.457 1.419 CMS Forward Calorimeter Fiber Specifications • Core : 600 ± 10 micron dia • Clad : 630 +5-10 micron dia • Buffer : 800 ± 30 micron dia • Core material : High OH- sythetic Silica • Clad material : Low Index Cladding Polymer • Buffer material : Acrylate • Core non-circularity : <5% • Clad concentricity : ± 3 microns • Buffer concentricity : ± 9 microns • nclad : 1.419 (@ 600 nm) • Att(@ 300 nm) : <0.15 dB/m • Att(@ 400 nm) : <50 dB/km • Att(@ 450 nm) : <30 dB/km • Att(@ 850 nm) : <20 dB/km • NA : 0.33 ± 0.02 • Core OH- content : 400 – 1000 ppm (high OH- Fiber) • Rmin curvature (short time)* : 6 cm/1 min • Rmin curvature (long time)* : 10 cm/2 months • Quantity : ~1000 km • Proof test (100% fibers) : 100 kpsi • Operating temp range : - 65 to +125 C • * (>98% optical transmission in 300 - 700 nm with no memory or breakage)

4. Buffer Clad Core Optics: HF-QP Specifications • Core : 600 ± 10 micron dia • Clad : 630 +5-10 micron dia • Buffer : 800 ± 30 micron dia • Core material : High OH- sythetic Silica • Clad material : Low Index Cladding Polymer • Buffer material : Acrylate • Core non-circularity : <5% • Clad concentricity : ± 3 microns • Buffer concentricity : ± 9 microns • NA : 0.33 ± 0.02 (Full acceptance cone : 38.5 degrees) • nclad : 1.419 (@ 600 nm) • Att(@ 300 nm) : <0.15 dB/m • Att(@ 400 nm) : <50 dB/km • Att(@ 450 nm) : <30 dB/km • Att(@ 850 nm) : <20 dB/km • Core OH- content : 400 – 1000 ppm (high OH- Fiber) • Rmin curvature (short time)* : 6 cm/1 min • Rmin curvature (long time)* : 10 cm/2 months • Quantity : 850 km • Proof test (100% fibers) : 100 kpsi • Operating temp range : - 65 to +125 C • * (>98% optical transmission in 300 - 700 nm with no memory or breakage)

5. Update on Fiber Tests - V

6. Spectral Measurements

7. Photodetector:HF Radiation Environment • radiation background simulations show improvement in the design of the shielding around the PMT region by a factor of ~two. There is no issue with the radiation dose or neutron flux where the PMTs are located. The numbers below are quoted per cm2 for 10 years. • All neutrons 2.54x1012 • Neutr.(E>100KeV) 1.63x1012 • Neutr. (E>20 MeV) 5.12x1011 • Ch. Hadrons 2.26x1010 • Muons 4.65x109 • Photons 1.53x1012 • Dose 7 krad

8. Optics: Radiation Field • Fluence of hadrons (E>100 keV) in cm-2 s-1 (upper plot) and radiation dose in Gy (lower plot) in the HF and its surroundings. The dose plot has been smoothed by taking running averages of the values, which slightly masks the dependence of dose on geometry details. Values are given for 5  105 pb-1.

9. E E 212 nm (5.86 eV) 260 nm (4.77 eV) 450 nm (2.75 eV) 670 nm (1.85 eV) NBOHC E’ Red Light? • Non-bridging Oxygen Hole Center (NBOHC):(Si-O.) 1.85 eV (670 nm) emission band remains controversial: This band is reported to have a 4.77 eV (260 nm) absorption band with 1.05 eV half-width. There is another absorption band at 1.97 eV (630 nm). • E’-center:(Si.) The emission band is at 2.75 eV (450 nm) and the absorption band is at 5.86 eV (212 nm).

10. Power-law Behavior ? • We can model the effects of radiation on the optical properties of quartz fibers. The model is based on binary molecular kinetics and the rate equations between these two species. • The most important feature is that it gives us the prediction power where we can estimate the energy resolution of HF as a function of dose. Silica Color Center

11. Irradiated QP and Attenuation - II • The attenuation of QP fibers strongly depend on the accumulated dose. The customary dependence is A(D) = a Db for each wavelength and this is supported by many measurements. This usual behavior is not obvious. It is possible that 240 Mrad data are wrong. Data being analyzed. • There is a fair agreement (trend) between the spectrometer data at 425 nm (Xenon) and the PMT data (Co60).

12. Cherenkov Light Transmission vs Dose • At 100 Mrad for example, 27% of light will be lost at 415 nm. But, there will be wavelength shift to red too.

13. Optics: Fiber Radiation Damage and Induced Resolution - I • Quartz fiber irradiation studies were carried out in the last several years. The induced attenuation profile shows that there is less absorbtion in 400-500 nm (PMT) region compared to either shorter or longer wavelengths. 54 Mrad QP

14. Optics: QQ/QP Comparison for Radiation Hardness - II 1.60 x 1016 e- = 64 MRad Total = 2.06 x 1016 e- = 80 MRad • The purity of the core material is paramount for radiation hardness of the fiber. In one case (left plot), the core is obtained from Heraeus and on the other case (right plot), from a less-known supplier of preforms. 450 nm 450 nm 610 nm 610 nm r = [I (QP)] / [I(QQ)] r = [I (QQ)] / [I (QP)]

17. 30 33 37 40

18. 30 33 37 40

20. 30 33 37 40