1. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 1 - Fiber optic sensors at INFN Frascati for CMS: past, present and future G.Basile(3), L. Benussi (1), S. Bianco (1), A.Brotzu (3), M.A.Caponero (2) S.Colafranceschi* (3), F.L. Fabbri(1), F. Felli (3), M.Ferrini(3) M.Giardoni(1), S.Grassini (6), E.Angelini (6), C.Lupi (5), M. Pallotta(1) A. Paolozzi(3), M.Parvis (4) L. Passamonti(1), D.Piccolo (1), D.Pierluigi(1) C. Pucci (3), A. Russo(1), G. Saviano (3) (1) Laboratori Nazionali di Frascati dell'INFN (2) Laboratori Nazionali di Frascati dell'INFN and ENEA Frascati (3) Laboratori Nazionali di Frascati dell'INFN and Sapienza Universita’ di Roma (4) Laboratori Nazionali di Frascati dell’INFN and Politecnico Turin (5) Sapienza Universita’ di Roma (6) Politecnico Turin *also at CERN, Geneva In collaboration with A.Sharma (CERN) Presented by Michele Caponero for the INFN-Frascati CMS group michele.caponero@enea.it michele.caponero@lnf.infn.it

2. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 2 - …in a well assorted collaboration INFN - National Laboratory of Frascati ENEA – Research Centre of Frascati Univ. Rome - Dept. Chemical and Material Eng. Turin Polytechnic – Dept. Electronic Eng. …quite interdisciplinary competences High Energy Physics Fiber Optic Sensing Chemistry Composite materials Electronics and Photonics THE CMS INFN FRASCATI GROUP

3. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 3 - Optical sensors for HEP Optical sensors of interest for HEP detectors are fast precise electrical noise - free magnetic field - insensitive rad-hard multiplexable Measurement of critical variables provided are Temperature Humidity Gas pollutants concentrations Strain Displacement

4. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 4 - The CMS INFN Frascati group has introduced Optical sensors in HEP since 1998 Bibliography 1.S.Bianco, M.Caponero, F.L.Fabbri Fiber Bragg Grating Sensors in CMS presented by S.Bianco at the March 2006 CMS week. 2.S. Bianco, M.A.Caponero, F.L. Fabbri, A.Paolozzi Omega-Like Fiber Bragg Grating Sensors as Position Monitoring Device: A Possible Pixel Position Detector in CMS? Frascati Preprint LNF - 06 / 13(NT) 23-05-2006. 3.L.Benussi et al., Results on Position Monitoring and Displacement> (Omega-Like Device) by Means of Fiber Bragg Grating Sensors for the BTeV Detector. Frascati Preprint LNF-03/15(IR) 10-09-2003. 4.L.Benussi et al., The Omega-Like: A Novel Device Using Fbg Sensors To Position Vertex Detectors With Micrometric Precision, Nucl. Phys. Proc. Suppl. 172 (2007) 263. 5.E.Basile et al., A novel approach for an integrated straw tube - microstrip detectors, IEEE Trans. Nucl. Sci. 53 (2006) 1375 6.E.Basile et al., Micrometric position monitoring using fiber Bragg grating sensors in silicon detectors arXiv:physics/0512255 FINUDA at DAFNE (1998) Operated Monitoring geometrical stability of uvtx detector BTeV at Fermilab (2002) R&D of Monitoring geometrical stability of uvtx R&D of Monitoring repositioning displacement of uvtx CMS (2005) Proposal for Monitoring geometrical stability of uvtx and repositioning CMS (NOW) R&D for gas pollutants for RPC CMS (NOW) Proposal T, H, gas pollutants in RPC upscope CMS (upgrade) Proposal for T, H, gas pollutants in hi-eta MPGD muon detectors

5. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 5 - Use of Fiber Optic Sensors for HEP introduced by our group in 1998 for the FINUDA Experiment FINUDA Use of optical fiber FBG sensors for real-time structural monitoring of the mechanical structure supporting the pixel vertex detector FINUDA: FIsica NUcleare a DAfne (Nuclear Physics at DAFNE)

6. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 6 - Common requirement for Vertex Detectors Supporting mechanical structure MUST be extremely ‘light’ AND very stable (... a no mass AND very stiff mechanical structure would be appreciated!) With ‘light’ mechanical supports it is hard assuming stable geometry: Deformation from mounting geometry thermal stress from mounting condition to data taking condition static mechanical loads Deformation from ‘last calibration’ by cosmic ray tracking backling effects by (even minor) thermal stress for service on/off Continuous alignment via track residuals is quite difficult !

7. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 7 - Availability of real-time metrological deformation monitoring CAN ALLOW continuous check of geometry/position stability, providing real-time alarm flag. If alarm flag occurs, alignment via track residuals is started. Fibre Bragg Grating (FBG) optical sensors: a novel but robust technology that can allow developing real-time metrological monitoring for HEP experiments

8. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 8 - Fibre Bragg Grating (FBG) sensor: Diffraction grating written inside the core of an optical fibre Grating is made by modifying the refraction index of a segment of the optical fibre Modified core: n3 Core: n2 (n2-n3 ≈ 10exp-3) Cladding: n1 Coating (mechanical protection) 250  m 5mm 8  m Optical fibre FBG location (embedded in the optical fibre core)

9. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 9 - Light propagating along the fiber can be diffracted by the grating Grating is designed to produce a narrow-band back-reflected signal Launched signal:  60nm Diffracted signal:   0.3nm @-3dB

10. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 10 - Wavelength of diffracted signal is a function of grating features (grating pitch , effective refraction index n eff ) Mechanical and thermal excitation of the grating modify the wavelength of the diffracted signal  = 1    1 pm(typical values)  T = 0.1 K   1 pm = 2  n eff

11. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 11 - Fibre Bragg Grating (FBG) sensor: optical strain gauge. Directly integrated in an optical fiber core Many sensors along the same optical fiber (WDM read-out) Long term stability in static and dynamic regime Electromagnetic field insensitivity Hostile environment endurance and mass lightness.   Monitored structure FBGs bonded with thermal/structural contact Structure ‘at rest’ FBG signal  Stressed structure FBG signal 

12. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 12 - FINUDA Use of optical fiber FBG sensors for real-time structural monitoring of the mechanical structure supporting the pixel vertex detector FINUDA: FIsica NUcleare a DAfne (Nuclear Physics at DAFNE)

13. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 13 - Mechanical structure of FINUDA vertex detector subject to deformations mainly due to microstrip on-board electronics FBG sensors attached on selected mechanical components to monitor significant structural deformations thermal and mechanical stress

14. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 14 - 11/Dic/2003 -03:08Massive ‘trips’ for some time due to e + injection 10:10DA  NE machine development: Microstrip and Tofino off 16:15Beam stable: Microstip and Tofino on 18:50Microstrip (OSIM1) ‘trip’: recovery procedure 19:15Microstrip stable: take data Microstrip ON Microstrip OFF Massive ‘trips’ of Microstrip Microstrip OFF Microstrip ON

15. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 15 - BTeV Experiment (planned to be run at FNAL; cancelled on Feb. 2005 !!!) R&D was performed in order to develop a device based on FBG sensors for monitoring repositioning of pixel detector with micrometric precision Mechanical support of pixel detector: to be removed/repositioned during/after beam steering hold in place by Pixel Support Cylinder

16. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 16 - 2/2 Pixel Support Cylinder Pixel ladder Actuator 1/2 Pixel Support Cylinder Omega-like  -like gauge: mechanical displacement gauge one end clamped at vacuum pipe fixed frame one end clamped at Pixel Support Cylinder

17. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 17 - Fixed frame Moving frame Omega-like displacement gauge: position of moving frame is worked out by deformation monitoring of  -like gauge; monitoring of deformation is accomplished by use of FBG sensors FBG sensors  FBG signal FBG signal    -like displacement gauge instrumented with FBG sensors one end clamped at vacuum pipe fixed frame one end clamped at the mechanical support of Pixel Detector

18. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 18 - Experimental tests at SiDet laboratory – FNAL Reference displacement measurements made by CMM (1  m resolution) Displacement imposed by motorised translation stage

19. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 19 -  [nm] Displacement [mm]  [nm] Experimental Linear fit Experimental Linear fit Test procedure: repeated ‘back and forth’ displacement; 10mm path length Experimental data expected to follow linear fit L. Benussi et al. Nuclear Physics B; 172 (2007) 263-265

20. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 20 - 8mm displacement4mm displacement # test Residuals of ‘back and forth’ displacement repeated 100times: Displacement [mm] Forward Backward Residual [  m] IV ord. Polinomial signal conditioning  = 5.6  m for 10mm long disp. range L. Benussi et al. Nuclear Physics B; 172 (2007) 263-265

21. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 21 - FBG sensor have fair ‘intrinsic’ Radiation Hardness capability FBG production: a grating is ‘written’ modifying the refractive index of the ‘core’ by a space-modulated UV beam. (UV modifies wrong Ge-Si, Ge-O and Ge-Ge bonds) Exposition to uniform ionising radiation affects the refraction index of the optical fiber mainly producing a ‘bias’ effect Optical fiber exposed to space-modulated UV FBG grating ‘written’ in the core of the optical fiber FBG exposed to uniform ionising radiation

22. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 22 - Effect of ionizing radiation on optical fibers already reported: Transmission attenuation (slightly wavelength-dependent) FBG sensing is based on narrow-band wavelength-encoded measurement, with excellent signal-to-noise ratio: FBG sensing has high tolerance to Transmission attenuation of optical fiber cables Typical signal form a string of 3 FBG sensors Typical FBG features Reflectivity>90% Reflective bandwidth @-3dB 15dB

23. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 23 - Neutron beam 14MeV - FNG facility at ENEA Research Centre ‘Frascati’ Total flux: 21.03  10 13 n/cm2 @14MeV (  35.97  10 13 n/cm2 @ 1MeV) Monitoring of FBG spectra during exposition M. Caponero et al. Proc. 10th conference Astroparticle, Particle and Space Physics, Detectors and Medical Physics Applications M. Barone, A. Gaddi (ed.) World Scientific Publishing (2007) 533 - 539

24. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 24 - Slight spectrum modification up to 12  10 13 /cm2 neutrons@14MeV No further modification up to 21  10 13 /cm2 neutrons@14MeV M. Caponero et al. Proc. 10th conference Astroparticle, Particle and Space Physics, Detectors and Medical Physics Applications M. Barone, A. Gaddi (ed.) World Scientific Publishing (2007) 533 - 539

25. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 25 -  -rays 60 Co – CALLIOPE facility at the ENEA Research Centre ‘Casaccia’ epoxy glue plastic frame optical fibre with FBG sensor FBG sensor location Set up for irradiation: FBG slightly stretched and glued on a plastic frame 400 cm CALLIOPE dose rate profile M. Caponero et al. Proc. 10th conference Astroparticle, Particle and Space Physics, Detectors and Medical Physics Applications M. Barone, A. Gaddi (ed.) World Scientific Publishing (2007) 533 - 539

26. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 26 -  [nm] Relative Time  [h] Spectra comparison after  1300 h exposition time   [nm] Amplitude [a.u.] M. Caponero et al. Proc. 10th conference Astroparticle, Particle and Space Physics, Detectors and Medical Physics Applications M. Barone, A. Gaddi (ed.) World Scientific Publishing (2007) 533 - 539 Dose rate  1349 Gy/h Dose  1.75 MGy

27. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 27 - PROPOSING FIBER OPTIC SENSORS FOR CMS RPC MUON DETECTORS Temperature monitoring Humidity monitoring Gas contaminants monitoring

28. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 28 - PRESENT ACTIVITY R&D on optical sensors for gas pollutants in the RPC detectors

29. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 29 - RPC MUON DETECTORS GAS recirculation closed loop The large detector volume and the expensive gas mixture make a closed loop recirculation system mandatory Gas total volume: 18 m 3 Active surface: 4000 m 2 Installed gaps: >800 Flux: 8 m 3 /h Gas total volume: 18 m 3 Active surface: 4000 m 2 Installed gaps: >800 Flux: 8 m 3 /h gas mixture (due to the presence of HF) tends to release some elements from zeolite framework, K and Ca increase in gas when currents increase. Fluorine is constantly produced and the zeolite traps it efficiently. Purifiers fail to filter HF and need to be regenerated. HF production increases with radiation Gas mix composition 95.2% of C2H2F4 4.5% of iC4H10 0.3% SF6 40% RU

30. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 30 - LED PHOTO DIODE 50 mm Proposing use of Plastic Optical Fiber: gas pollutants monitoring POF: Plastic Optical Fiber Large diameter plastic optical fiber POF sensors for gas pollutants based on the technique of the ‘evanescent wave attenuation measurement’ (light transmitted at the core/cladding interface) Sensor fabrication 1)The plastic cladding of the fiber is removed 2)The fiber is coated with a chemical substance ‘sensitive’ to the pollutant to be monitored Sensing principle 1)Optical property of the coating is affected by the quantity of pollutant that has been ‘intercepted’ 2)The variation of the light intensity transmitted by the coated fiber is related to the quantity of ‘intercepted’ pollutant. NOTE: Usually irreversible cumulative measurement (!!)

31. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 31 - PECVD Plasma Enhanced Chemical Vapour Deposition Turin Polytecnic Department of Electronic Engineering

32. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 32 - 10  m Ag 2 S before after POF sensor for H 2 S Coating: Ag

33. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 33 - ppm sensitivity POF ELECTROCHEMICAL Results in use of POF sensor for H 2 S sensing: ……..R&D in progress for HF detection

34. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 34 - Proposing use of Fiber Optic Sensors for RPC upscope & upgrade THE NEAR FUTURE We propose to install a distributed system based on FBG technology to monitor Temperature ad Relative Humidity of upscope RPC detector (and possibly gas pollutants) THE FAR FUTURE Optical sensors for hi-eta MPGD: T, RH, pollutants

35. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 35 - RPC MUON DETECTORS Temperature and Humidity monitoring is of paramount importance in RPC detectors Humidity RH affects bakelite resistivity R Temperature T affects RPC polarization voltage V

36. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 36 - RH sensing by FBG sensors: well established application ‘State of the Art’ resolution: 5%RH Proper choice of moisture sensitive polymer coating can improve resolution

37. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 37 - Temperature sensing by FBG sensors Typical resolution: 0.1K (at room temperature) Temperature dependence of glass refraction index Thermal expansion coefficient of glass  T [K] M. Caponero et alt.; “long term thermal deformation and creep monitoring of CFRP components” – ENEA Internal Report

38. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 38 - Barrel Endcap Sensors in Upscope endcaps Baseline Six stations in the Barrel Four station in the Endcap up to  = 2.1 Baseline Six stations in the Barrel Four station in the Endcap up to  = 2.1 However, due to technical and financial reasons, only three layers up to  = 1.6 are present in the endcap region.

39. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 39 - in-cable optical fiber T sensing (metal coated FBG sensor) RH sensing (FBG embedded in moisture sensitive layer) bare optical fiber Technological specimen

40. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 40 - FBG sensing system (TDM - Time Division Multiplexing): Optical lines sequentially addressed to single-channel Interrogation System (WDM – Wavelength Division Multiplexing): Multiple FBG sensors arranged in-series on one optical line Optical Switch Interrogation System Local Controller Optical Connector Fiber Optic ribbon cable Feed through Optical connector receptacle Optical fibers with FBG sensors (Temperature; RH) to/from Remote Controller RPCs

41. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 41 - Conclusions & outlook Optical sensors have been successfully applied in HEP detectors in our past experiments and R&D (FINUDA, BTEV) for strain, displacement, temperature monitoring –precise, reliable, rad-hard. Started R&D on optical sensors for detection of RPC gas contaminants, to be tested at GIF (2010) If R&D successful, proposal for monitoring gas contaminants in endcaps RPCs (1ppm) Proposed use of optical sensors for T(0.1K) and RH (2÷5%) monitoring in new upscope RPCs In 2011 finalize proposal for use of optical sensors in hi-eta MPGD

42. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 42 -

43. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 43 - References 1.S.Bianco, M.Caponero, F.L.Fabbri Fiber Bragg Grating Sensors in CMS presented by S.Bianco at the March 2006 CMS week. 2.S. Bianco, M.A.Caponero, F.L. Fabbri, A.Paolozzi Omega-Like Fiber Bragg Grating Sensors as Position Monitoring Device: A Possible Pixel Position Detector in CMS? Frascati Preprint LNF - 06 / 13(NT) 23-05-2006. 3.L.Benussi et al., Results on Position Monitoring and Displacement> (Omega-Like Device) by Means of Fiber Bragg Grating Sensors for the BTeV Detector. Frascati Preprint LNF-03/15(IR) 10-09-2003. 4.L.Benussi et al., The Omega-Like: A Novel Device Using Fbg Sensors To Position Vertex Detectors With Micrometric Precision, Nucl. Phys. Proc. Suppl. 172 (2007) 263. 5.E.Basile et al., A novel approach for an integrated straw tube - microstrip detectors, IEEE Trans. Nucl. Sci. 53 (2006) 1375 6.E.Basile et al., Micrometric position monitoring using fiber Bragg grating sensors in silicon detectors arXiv:physics/0512255 7.S.Bianco et al., Chemical study of the CMS RPC closed loop gas system, CMS note 2010 - 007 8.G.Saviano (for the CMS RPC Collaboration) Results on chemical analysis in the CMS RPC closed loop, presented at RPC2010, Darmstadt (Germany).

44. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 44 - ADDITIONAL MATERIAL

45. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 45 - Proposed Plan & Milestones Optical fiber activity for RPC 1.2010 1.May 1.Expose POF to high-rad (GIF) 2.Begin design for T, H monitoring FBG sensors integration in upscope endcaps 2.June 1.End of last run of Closed Loop gas purifier characterization @ low-rad 3.July 1.Moving RPC’s from low-rad to high-rad (GIF). Characterize purifiers. Goals: confirm release of contaminants, measure purifiers lifetime, extrapolate to safe lifetime for CMS between purifier regeneration 4.October 1.Install and characterize POF for F- detection @GIF 5. 2.2011 1.January 1.End of 3.1 2.Begin characterization, testing and installation of FBG sensors for T, H monitoring in upscope endcaps 2.March 1.End of 4.1 2.Decision: POF for F- detection in upscope endcaps ? 3.April 1.Begin conceptual design of FBG and POF for hi-eta region MPGD 2.………….

46. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 46 - POF sensor for H 2 S sensing R&D in progress for F - detection Preparation of POF sensor. Cladding chemical Ablation (etilacetate, 40s) POF Sensor sensitivity (first plot) compared to electrochemical sensor sensisivity (plot in the middle) ppm sensitivity POF electrochemical POF electrochemical

47. M.Caponero (INFN and ENEA) - CMS Frascati - Optical sensors for CMS - Upgrade Workshop April 2010 - 47 - F - production and current increasing in upstream gap preliminary F - before zeolite F - after zeolite