Irradiation of Fibres at SIS18

Introduction

For FAIR, timing sensitive equipment will be installed in the niches of SIS100. It might be possible, that fibres to the niches will be guided via the SIS100 itself. Those fibres must be radiation hard. In order to test fibres under a realistic conditions, we try to irradiate fibres directly under the extraction septum of SIS18 during 2014. The following types of fibre are irradiated.

• Super RadHard Single-Mode Optical Fibre (Draka)
• non radiation hard single mode fibre

The fibres are connected to outside the ring using non-radation hard (NRH) and Super RadHard (SRH) fibres. This allows measuring the attenuation and bit error rates in-situ and during beam operation.

Setup

Figure 1: Setup at the extraction septum in SIS18/S06

• Blue: Radiation Sensors
  • Top: Alanine Sensors
  • Bottom: Neutron and other detectors
• Green: Cables connecting to BG1 outside SIS18
  • light green left: NRH "Septum" (four fibres)
  • light green right: NRH "Leiter" (four fibres)
  • dark green: SRH (four fibres)
• Orange (left): 600m SRH fibre "Septum" as close as possible to the extraction septum.
• Orange and Yellow (left): 1600m SRH fibre and 100m NRH fibre "Septum" just 40 cm away from the septum
• Orange and Yellow (right): 1600m SRH fibre and 100m NRH fibre "Leiter" just below the passerelle.

Connection from SIS18 to BG1

The fibres to be irradiated are connected from both ends

• via SRH (dark green)
  • 600m SRH "Septum"
  • 1600m SRH "Leiter"
• via NRH "Septum" (light green)
  • 100m NRH "Septum"
  • 1600m SRH "Septum"
• via NRH "Leiter" (light green)
  • 100m NRH "Leiter"
  • unused

Some Pictures

• Left: "Septum", Right: "Leiter" - ion beam from left to right:
  

• "Septum" 600m SRH:
  

• "Septum" top/left: 600m SRH, bottom/right: 1600m SRH and 100m NRH:
  

• "Septum" top: 600m SRH, bottom/left: 1600m SRH and 100m NRH (from the back):
  

• "Leiter" SRH 1600m and 100m NRH:
  

First Data

Figure 1: First data of irradiation of fibres at the extraction septum of SIS18.
The figures shows first and preliminary data of the five irradiated fibres, which are close to the extraction septum of SIS18. The approximate length of the fibres is given in the figure (NRH: non rad-hard fibre, SRH super rad-hard fibre). The values for attenuation are normalized to 1 km. The uncertainties are stated in the figure: Please note, that the values for the non rad-hard short (100m) fibres have large uncertainties. The values of the accumulated dose have been obtained using a gamma and a neutron detector at the ladder in combination with the values obtained from the Alanine sensors close to the fibres (septum and ladder), see figure of the set-up on top.

-- DietrichBeck - 24 Jul 2015