HF PRR – 16 February 2001 1

HF PRR – 16 February 2001 2

HF PRR – 16 February 2001 3

Core : 600 ± 10 micron diaClad : 630 +5-10 micron diaBuffer : 800 ± 30 micron dia Core material : High OH- sythetic SilicaClad material : Low Index Cladding PolymerBuffer material : AcrylateCore non-circularity : <5%Clad concentricity : ± 3 micronsBuffer concentricity : ± 9 microns

nclad : 1.419 (@ 600 nm)Att(@ 300 nm) : <0.15 dB/mAtt(@ 400 nm) : <50 dB/kmAtt(@ 450 nm) : <30 dB/kmAtt(@ 850 nm) : <20 dB/kmNA : 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 monthsQuantity : ~1000 kmProof test (100% fibers) : 100 kpsiOperating temp range : - 65 to +125 C

* (>98% optical transmission in 300 - 700 nm with no memory or breakage)

CMS Forward Calorimeter Fiber SpecificationsCMS Forward Calorimeter Fiber SpecificationsCMS Forward Calorimeter Fiber SpecificationsCMS Forward Calorimeter Fiber Specifications

1.457

1.419

HF PRR – 16 February 2001 4

Optics: HF-QP SpecificationsOptics: HF-QP SpecificationsOptics: HF-QP SpecificationsOptics: HF-QP Specifications

Core : 600 ± 10 micron diaClad : 630 +5-10 micron diaBuffer : 800 ± 30 micron dia Core material : High OH- sythetic SilicaClad material : Low Index Cladding PolymerBuffer material : AcrylateCore non-circularity : <5%Clad concentricity : ± 3 micronsBuffer concentricity : ± 9 micronsNA : 0.33 ± 0.02 (Full acceptance cone : 38.5 degrees)

nclad : 1.419 (@ 600 nm)Att(@ 300 nm) : <0.15 dB/mAtt(@ 400 nm) : <50 dB/kmAtt(@ 450 nm) : <30 dB/kmAtt(@ 850 nm) : <20 dB/kmCore OH- content : 400 – 1000 ppm (high OH- Fiber)

Rmin curvature (short time)* : 6 cm/1 min

Rmin curvature (long time)* : 10 cm/2 monthsQuantity : 850 kmProof test (100% fibers) : 100 kpsiOperating temp range : - 65 to +125 C

* (>98% optical transmission in 300 - 700 nm with no memory or breakage)

Core

CladBuffer

HF PRR – 16 February 2001 5

Spectral AttenuationFSHA600630800 .33NA

LOT: KWA-01ADATE: 04/14/02Operator: Ray

0

5

10

15

20

25

30

35

40

45

50

55

60

65

70

75

80

85

90

95

100

400 450 500 550 600 650 700 750 800 850Wavelength (nm)

Att

enu

atio

n (

dB

/km

)

Att. 1

Att. 2

Att. 3

Att. 4

Update on Fiber Tests - VUpdate on Fiber Tests - VUpdate on Fiber Tests - VUpdate on Fiber Tests - V

HF PRR – 16 February 2001 6

Spectral MeasurementsSpectral MeasurementsSpectral MeasurementsSpectral Measurements

Spectral Attenuation QP600

-1

0

1

2

3

4

365 415 465 515 565 615 665 715 765 815Wavelength (nm)

Rel

ativ

e A

tten

uat

ion

(d

B/m

)

120 MRad

80 MRad

20 MRad

HF PRR – 16 February 2001 7

Photodetector:Photodetector:HF Radiation EnvironmentHF Radiation Environment

Photodetector:Photodetector:HF Radiation EnvironmentHF 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

HF PRR – 16 February 2001 8

Optics: Radiation FieldOptics: Radiation FieldOptics: Radiation FieldOptics: 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.

25

50

75

100

125

150

175

200

225

1000 1050 1100 1150 1200 1250 1300 1350 1400 1450 1500

z (cm)

1016

1015

1014

1013

1012

1011

25

50

75

100

125

150

175

200

225

1000 1050 1100 1150 1200 1250 1300 1350 1400 1450 1500

z (cm)

106105

104

103

102

102

HF PRR – 16 February 2001 9

Red Light?Red Light?Red Light?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).

260 nm

NBOHC

(1.85 eV)

670 nm

(4.77 eV)

E

E’

212 nm

(2.75 eV)450 nm

(5.86 eV)

E

HF PRR – 16 February 2001 10

Power-law Behavior ?Power-law Behavior ?Power-law Behavior ?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.

fcim

nn

fn

n

f

f

DCq

nifRtqqtq

Rtqnqtq

dt

dDCfDKqR

ticsonfromKineRateEquatiRqdt

dDK

dt

dqdt

dDCfD

dt

dq

CDq

)(

)2(]1/[)(

])1(1[)(

)(

)(

0

00

)1/(1100

1

1

Silica Color Center

HF PRR – 16 February 2001 11

Irradiated QP and Attenuation - IIIrradiated QP and Attenuation - IIIrradiated QP and Attenuation - IIIrradiated 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).

PRELIMINARYAttenuation with Dose for HF-QP

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0 50 100 150 200 250 300Dose (MRad)

Att

en

uati

on

(/m

)

a=0.10, b=0.3

a=0.14, b=0.5

Spectrometer Data425 nm

HF PRR – 16 February 2001 12

Cherenkov Light Transmission Cherenkov Light Transmission vsvs Dose DoseCherenkov Light Transmission Cherenkov Light Transmission vsvs Dose Dose

At 100 Mrad for example, 27% of light will be lost at 415 nm. But, there will be wavelength shift to red too.

HF PRR – 16 February 2001 13

Optics: Fiber Radiation Damage and Induced Optics: Fiber Radiation Damage and Induced Resolution - IResolution - I

Optics: Fiber Radiation Damage and Induced Optics: Fiber Radiation Damage and Induced Resolution - IResolution - 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

HF PRR – 16 February 2001 14

Optics: QQ/QP Comparison for Radiation Hardness - IIOptics: QQ/QP Comparison for Radiation Hardness - IIOptics: QQ/QP Comparison for Radiation Hardness - IIOptics: QQ/QP Comparison for Radiation Hardness - II

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

610 nm

Total = 2.06 x 1016 e- = 80 MRad 1.60 x 1016 e- = 64 MRad

= [I (QP)] / [I (QQ)] = [I (QQ)] / [I (QP)]

450 nm

610 nm

HF PRR – 16 February 2001 15

HF PRR – 16 February 2001 16

HF PRR – 16 February 2001 17

30

33

37

40

HF PRR – 16 February 2001 18

30

33

37

40

HF PRR – 16 February 2001 19

Ieta dD/dt[rad/s]

a (95% Conf. Bounds)[dB/m]

b (95% Conf. Bounds)

30 2.5 x 10-4 1.37 (-1.36, 4.12) 0.39 (0.21, 0.58)

33 2.0 x 10-3 4.74 (-0.46, 9.93) 0.59 (0.47, 0.72)

37 3.2 x 10-2 2.43 (0.40, 4.45) 0.72 (0.58, 0.86)

40 2.9 x 10-1 1.28 (0.75, 1.82) 0.79 (0.68, 0.91)

HF PRR – 16 February 2001 20

30

3337

40

HF PRR – 16 February 2001 21