CMS GEM at Frascati

CMS GEM activity of Frascati group Main Page can be found here

Moire Interferometry NEW

The moire effect is utilized in experimental mechanics to measure the deformation of bodies subjected to external loads. Deformations are viewed as contour maps of displacement and are referred to as fringe patterns. In-plane and out-of-plane displacement fringe patterns can be generated using techniques of geometric moire, shadow moire, and interferometric moire.

Moire Interferometry results

* CMS_GEM_stretching_Meet2014_1201V2.pptx: GEM foils stretching techniques

* single pixel.pdf:

* phase shift in one pixel line.pdf:

* self generated and comparison April 22, 2015.pdf:

* Moire interferometery April 25, 2015.pdf:

* Moire updates may 09, 2015.pdf:

* Moire_resolution.ppt: Moire_resolution.ppt

* Moire_summary.pptx: Moire_summary.pptx

Fibre Bragg Grating

Use of FBG sensors to validate the stretching system

A Fiber Bragg Grating (FBG) is an intrinsic optical sensor consisting in a Bragg grating made in a short segment of optical fiber whose refractive index has been modulated. A FBG back-reflects a particular wavelength (Bragg Wavelength; actually, a very narrow bell-shaped spectrum) and transmits all others. The value of the Bragg Wavelength depends on the pitch of the grating and on the effective refractive index at the grating. Mechanical disturbances modify the pitch of the grating. A FBG can thus be used as a strain gauge, since the variation of the pitch produces a shift of the Bragg Wavelength. The sensitivity to strain (relative elongation) is about 1 microStrain (1 ppm). Thermal disturbances modify the effective refractive index at the grating. A FBG can thus be used as a temperature sensor, since the variation of temperature produce a shift of the Brag Wavelength. The sensitivity to temperature variation is about 0.1 K.

In order to validate the mechanical stretching technique used in GE1/1 assembly we installed a network of FBGs on the triple-GEM stack of a GE1/1 chamber prototype. The network of FBGs works as a distributed strain monitoring sensing system which measure the stretching of the GEM foils at multiple locations. The gage length of each sensor is 10 mm; six sensors are present on each foil; all sensors on the same foil are connected in-series on one optical fiber an plugged to one channel of the electro-optic DAQ device. The position of the sensors on the foil plane is identical on the three foils so that the stretching of the three foils can be easily compared.

FBG sensors results

* FBGs_updates_May_05_2015.pdf:

* FBGs_mutual_comparison_May11_2015.pdf:

Meetings, Conferencs and Reports

- Poster presented in 13th PISA meeting at Elba, May 25-30, 2015, title "Fiber Bragg Grating (FBG) sensors as flatness and mechanical stretching sensors"

- PISA MEETING REPORT presented and submitted by Saleh Muhmmmad

- Poster presented in 4th EIROfourm School on Instrumentation (15-19 June 2015) Garching Germany, title " Material studies for gaseous muons detectors at HL-LHC"

- Three Months work report in INFN Frascati (March 10 to June 10, 2015) submitted by Saleh Muhammad

Topic attachments
I Attachment History Action Size Date Who Comment
Unknown file formatpptx CMS_GEM_stretching_Meet2014_1201V2.pptx r1 manage 14223.6 K 2015-05-11 - 09:42 SalehMuhammad  
PDFpdf FBGs_mutual_comparison_May11_2015.pdf r1 manage 3489.4 K 2015-06-12 - 14:40 SalehMuhammad  
PDFpdf FBGs_updates_May_05_2015.pdf r1 manage 2757.8 K 2015-06-12 - 14:39 SalehMuhammad  
PDFpdf Moire_interferometery_April_25_2015.pdf r1 manage 1958.9 K 2015-05-18 - 08:45 SalehMuhammad  
PowerPointppt Moire_resolution.ppt r1 manage 1203.5 K 2015-07-08 - 11:36 SalehMuhammad  
Unknown file formatpptx Moire_summary.pptx r1 manage 932.2 K 2015-11-20 - 18:22 SalehMuhammad  
PDFpdf Moire_updates_may_09_2015.pdf r1 manage 1186.7 K 2015-05-18 - 08:52 SalehMuhammad  
PDFpdf Pisa_meeting_summary.pdf r1 manage 8963.4 K 2015-07-08 - 10:41 SalehMuhammad  
PDFpdf Poster_FBG_Elba2015v0.pdf r1 manage 828.6 K 2015-07-08 - 10:26 SalehMuhammad  
Unknown file formatpptx Poster_FBG_Elba2015v0.pptx r1 manage 13772.5 K 2015-07-08 - 10:28 SalehMuhammad  
PDFpdf Poster_for_EIROfourm_School.pdf r1 manage 901.3 K 2015-07-08 - 10:34 SalehMuhammad  
Unknown file formatpptx Poster_for_EIROfourm_School.pptx r1 manage 3128.3 K 2015-07-08 - 10:36 SalehMuhammad  
Unknown file formatpptx Self_generated_image_April_22_2015.pptx r1 manage 5909.3 K 2015-05-18 - 08:58 SalehMuhammad  
PDFpdf Three_months_work_report_in_Frascati_INFN_Lab.pdf r1 manage 9445.5 K 2015-07-08 - 11:03 SalehMuhammad  
Unknown file formatpptx Three_months_work_report_in_Frascati_INFN_Lab.pptx r1 manage 38624.8 K 2015-07-08 - 11:05 SalehMuhammad  
PDFpdf phase_shift_in_one_pixel_line.pdf r1 manage 390.5 K 2015-05-18 - 08:29 SalehMuhammad  
Unknown file formatpptx pisa_meeting_summary.pptx r1 manage 26112.4 K 2015-07-08 - 10:42 SalehMuhammad  
PDFpdf self_generated_and_comparison_April_22_2015.pdf r1 manage 1958.9 K 2015-05-18 - 08:41 SalehMuhammad  
PDFpdf single_pixel.pdf r1 manage 282.4 K 2015-05-18 - 08:24 SalehMuhammad  
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Topic revision: r8 - 2015-12-04 - SalehMuhammad
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