Optical absorption in commercial single mode optical fibres for the LHC machine

The optical absorption of light at 1310 nm and 1550 nm in various commercially available Single Mode (SM) fibres samples has been studied. The absorption was measured as a function of dose, dose rate, temperature and light power. The samples were irradiated with gamma rays from a 60Co source and exposed to a complex radiation field from high energy physics. One fibre sample with an F-doped core exhibits extreme low absorption of light at 1310 nm during irradiation up to doses of at least 100 kGy

Design and test of the optical fiber assemblies for the scalar magnetic field sensor aboard the JUICE mission

A set of optical fiber assemblies has been developed and successfully qualified for its use on a European space science mission to the icy moons of Jupiter (Jupiter Icy Moons Explorer, JUICE), to be launched in 2022. The paper gives an overview of the design challenges, the test methods used for failure detection and screening of the optical fiber cable assemblies as well as the further testing performed in the frame of a lot acceptance qualification

Systemdemonstrator CHORUS

Das Fraunhofer INT hat in einem Konzept "CHORUS - Car Horns used as Sirens" dargelegt, wie man die Hupen von geparkten Pkw ähnlich Sirenen zur Bevölkerungswarnung einsetzen kann. Um den Nachweis der prinzipiellen technischen Machbarkeit des Konzepts zu erbringen, wurde ein Systemdemonstrator "CHORUS" realisiert, der alle relevanten Schritte der Prozesskette einer entsprechenden Alarmierung mittels eines LabVIEW-VKIs (VI=Virtuelles Instrument) nachbildet. Dazu gehört die Generierung eines Alarmierungssignals in einer Leitstelle, die Konvertierung des Signals gemäß der Protokolle unterschiedlicher terrestrischer Funksender, die Kontrolle des Signals auf der Empfangsseite, die Weiterverarbeitung der Daten fahrzeugseitig und das Erzeugen eines charakteristischen Warn-Signals mit standardmäßigen Pkw-Hupen. Die Festlegung des geographischen Alarmierungsbereiches in der simulierten Leitstelle in Form eines Polygonzuges erfolgt dabei interaktiv in einer grafischen Oberfläche, in die mittels eines grafischen lnformationssystems (GIS) Kartenmaterial eingebunden ist. Ein Alarm wird auf der Empfangsseite nur dann ausgelöst, wenn die per GPS-Sensor erfasste Position des (simulierten) Fahrzeugs innerhalb des Polygons liegt

Cloning of double stranded DNAs derived from polysomal mRNA of maize endosperm: isolation and characterisation of zein clones.

Starting from polysomal RNA of developing maize endosperm and applying the cloning procedure of integrating dsDNA into the Pst I site of plasmid pBR 322, clones containing sequences complementary to endosperm mRNAs were obtained. 25 per cent of these clones were identified as containing zein specific DNA sequences which hybridized either with the zein mRNA coding for the 22 000 Mr protein or with the zein mRNA coding for the 19 000 Mr protein. The zein-specific DNA inserts of the recombinant plasmids were further characterized by restriction enzyme analysis

Fibre Bragg gratings as high dose radiation sensors?

We have measured for the first time the shift of the Bragg wavelength and other parameters of fibre Bragg gratings (FBGs) exposed to gamma-radiation at different wavelengths up to a dose of 100 kGy. The results show that the FBG sensitivity to radiation increases from 820 nm to 1516 nm so that FBGs with higher Bragg wavelength, e.g. 1550 nm, are good candidates for high dose radiation sensing: no saturation was observed up to 100 kGy and the measured wavelength shift was fairly independent on the radiation dose rate

Radiation hard optical fibers

Meanwhile there exist fibers of nearly all types that show sufficient radiation hardness in lengths necessary for the respective application. Hydrogen loading or treatment and thermal or photo bleaching can harden certain fibers or fiber links

High radiation hardness of a hollow core photonic bandgap fibre

A 19-cell hollow core photonic bandgap fiber with a core diameter of 20 µm and an attenuation minimum of about 11dB/km at 1590 nm was exposed to continuous 60Co gamma radiation and pulsed electrons up to dose values of 10 Exp4 Gy and 100 Gy, respectively. The attenuation increase during continuous or after pulsed irradiation was at least 30 times or 100 times lower, respectively, than observed with the best conventional single-mode fibers. Furthermore a slight reduction of the width of the transmission band after a total gamma dose of 1.4 × 10 Exp5 Gy was observed

Influence of coating material, cladding thickness, and core material on gamma radiation sensitivity of pure silica core-step-index fibres

We investigated the influence of core material, cladding thickness, drawing speed, and coating material on the radiation sensitivity of pure silica core step-index fibers with high OH-content. The gamma radiation-induced attenuation at 660 nm and 850 nm of fibers by different manufacturers are compared

Influence of manufacturing parameters and temperature on the radiation sensivity of fiber Bragg gratings

For the first time the radiation sensitivity of Bragg gratings was investigated as a function of hydrogen loading pressure before and fiber tension during grating inscription, of the recoating procedure, and of the grating temperature. At -50°C the radiation-induced Bragg wavelength shift was about two times higher than at room temperature. This should be considered when selecting Bragg gratings e.g., for certain space applications

Macro-bending influence on radiation induced attenuation in optical fibres

Influence of the bending radius on the radiation resistance of single-mode glass optical fibres is discussed in this paper. Radiation induced attenuation in single-mode fibres shows discrepancies when measured in specific geometries allowing high dose rates. A series of dedicated tests shows that this phenomenon is related to low bending radius. For irradiation tests of single-mode optical fibres, the spool radius should therefore be carefully chosen