1. FBG@nTOF Status Francisco Rogelio Palomo University of Sevilla nTOF meeting Lisbon, 13 th -15 th Dec 2011

2. Status and Motivation Fco. Rogelio Palomo Pinto University of Sevilla A FBG mirror is a periodic modulation of the refractive index in an optical fibre core A FBG mirror reflects the incident light in only one wavelength: FBG@nTOF experiment started in November 2011, still ongoing. FBG sensors are periodic modulation of the refractive index of a photosensitive optical fiber (SiO 2 core doped with GeO 2 ). FBG sensors transduce heat, strain and ionization into wavelength shift (very low thermal inertia, <1 cm length, 8  m core diameter) Two targets under fast neutron beam: Fresh Photosensitive Optical Fiber in the neutron dump for damage analysis FBG sensors in the FIC chamber for dose damage and transduction analysis FBG sensors are inscribed in photosensitive optical fibers (by means of UV laser ilumination) and stimulated by light: Fiber Bragg Gratings, A.Othonos, Rev. Sci.Instrum. 68(12) Dec 1997

3. Fco. Rogelio Palomo Pinto University of Sevilla Neutron Damage on Photosensitive Optical Fibers 5 meters of fresh photosensitive optical fiber (Nufern NF1, acrylate coated) No FBG. Pasive irradiation experiment, parasitic mode. After irradiation (1 month or more), analysis of Raman spectra to study neutron damage. This experiment is ongoing, only 5 five days of irradiation due to PPAC installation and the premature PS stop.

4. Fco. Rogelio Palomo Pinto University of Sevilla Proton Ionization Experiments CNA Sevilla Influence of the Fiber Coating on the proton irradiation sensitivity of Fiber Bragg Gratings E.Curras et al. RADECS 2011 Proceedings (accepted for Transactions on Nuclear Science). On the use of FBG sensors as temperature-based Beam Profile Monitors F.R.Palomo et al. DITANET 2011 2010: Ionization damage analysis (15 MGy, 13 MeV protons, 90ºC during irradiation ): acrylate coated FBG fibers recovers after natural annealing. 2011: Ionization detection On/Off Beam, 0.5, 1, 2, 5, 10 Mrad 2011:13.3 MeV, 1.7e10 p/cm 2 -s, on air, LET CORE ~7 keV/  m

5. FBG sensors at FIC Chamber Fco. Rogelio Palomo Pinto University of Sevilla A group of 7 FBG sensors (acrylate coated) in vacuum, inside the FIC Chamber (parasitic mode) 4 FBGs under the neutron beam, 3 FBGs for reference Fast Interrogation (SM130 Full C Band Tunable Laser, 1 KHz) Supported in kapton and plexyglas (light elements, thermal isolation) Ready to Measure, waiting for beam (vacuum feedthroug problems) Two Objectives: 1. To catch a fast thermal signal, in analogy with the proton experiment (in vacuum to avoid thermalization with air) 2 To study fast neutron damage effects in the FBG sensors

6. Remote Monitoring Status Fco. Rogelio Palomo Pinto University of Sevilla Remote monitoring by means a dedicated server (Passpartout, nTOF pit) Access through CERN Terminal Server Automatic Data Log with a dedicated server (Phyleas, Sevilla) Working fine! CERNTS.cern.ch Standard Windows Desktop session Passpartout @nTOF Dump Chamber Phyleas @Sevilla Univ. (Data Logger) Automatic Secure FTP RemoteTerminal FBG sensors @Frame Support SM130 Laser Interrogator

7. Stoppers Fco. Rogelio Palomo Pinto University of Sevilla The FBG setup in vacuum needs optical feedthrough Simple solutions innefective, a real stopper. A new optical feedthrough from SEDI is on the way (very expensive) The November campaign finished with the PS injector premature closure.

8. FBG@FIC could start at mid January or February 2012. Fiber Damage experiment will restart in January 2012 We hope to receive the new fiber optical feedthrough during December 2011 Starting collaboration with Athenas University for dosimetric calibration of the whole FBG@nTOF setup using CR-39 sheets at the neutron dump and at the beam exit inside the FIC chamber. Previsions Fco. Rogelio Palomo Pinto University of Sevilla

9. Thanks for Your Attention rogelio@gte.esi.us.es