40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
  PSL  Not logged in ELOG logo
Entry  Sun Sep 23 18:28:04 2012, tara, Notes, Drawings, 1.45" refcav mount cav_mount_assembly2.PDFcav_mount_assembly2.PDFcav_mount_bottom.PDFcavity_mount_top.PDF
    Reply  Thu Sep 27 17:13:13 2012, tara, Notes, Drawings, 1.45" refcav mount cav_mount_assembly_3.PDFpeek_v2.PDF
       Reply  Thu Oct 4 23:28:06 2012, tara, Notes, RefCav, comsol simulation for cavity suspension cavity_sagging_2012_10_04.pngcavity_sagging_0_2012_10_04.png
          Reply  Wed Oct 10 01:38:49 2012, tara, Notes, RefCav, comsol simulation for cavity suspension 
             Reply  Wed Oct 10 21:31:57 2012, tara, Notes, RefCav, comsol simulation for cavity suspension plot.pngcavity_sagging_0_2012_10_04.png
                Reply  Thu Oct 11 19:07:06 2012, tara, Notes, RefCav, comsol simulation for cavity suspension plot_degree_area.png
                   Reply  Sat Oct 13 23:38:08 2012, tara, Notes, RefCav, comsol simulation for cavity suspension dis_tilt_12_45.png
                      Reply  Tue Oct 16 01:14:00 2012, tara, Notes, RefCav, comsol simulation for cavity suspension disx_y.png
                         Reply  Wed Oct 24 11:16:52 2012, tara, Notes, RefCav, comsol simulation for cavity suspension analyzed_plot.pnganalyzed_plot.figIMG_1914.jpg
                            Reply  Fri Oct 26 04:05:18 2012, tara, Notes, RefCav, comsol simulation for cavity suspension plot_line.pngplot_line.pngplot_line.pngplot_angle.png
                               Reply  Tue Feb 4 01:11:01 2014, tara, Notes, RefCav, comsol simulation for cavity suspension 
                                  Reply  Tue Mar 4 18:53:48 2014, tara, Notes, RefCav, comsol simulation for cavity suspension hist_small_mount_err.pnghist_small_mount_err.fig
       Reply  Wed Oct 31 16:00:13 2012, tara, Notes, Drawings, 1.45" refcav mount Assem2.PDFAssem2_1.PDF
          Reply  Thu Nov 8 20:00:33 2012, tara, Notes, Drawings, 1.45" refcav mount 7x
Message ID: 1063     Entry time: Tue Oct 16 01:14:00 2012     In reply to: 1062     Reply to this: 1065
Author: tara 
Type: Notes 
Category: RefCav 
Subject: comsol simulation for cavity suspension 

I checked the cavity length sensitivity to horizontal acceleration ( normal to the beam line axis). Unlike the result from vertical acceleration, the cavity length did not change smoothly with the position.  For the optimum point(30 degree, 1.18 inch apart), the displacement sensitivity due to horizontal acceleration is about a factor of 2 larger than that of vertical acceleration.

 Since both horizontal(H) and vertical(V) seismic noise on the table are comparable [psl:xxx], I want to make sure that there will be no serious displacement noise due to acceleration on vertical direciton.

On the COMSOL model, I fixed only one side of the support to push against horizontal acceleration (see pic). As the support can only push against the cavity, not pull. It should make more sense to use this boundary condition.

For the effect from H acceleration, I varied the angle from 12 to 42 degree, and distance from 0.8 to 1.2 inch. The displacement did not change smoothly with the support positions. So I could not tell which way I should choose for the optimum support. However, the displacement seems to be around 2x10^-10 inch for most of the positions. [the unit on the y axis of the plot should be inch per acceleration]. disx_y.png

For the optimum support (1.18 Inch, 30 degree) the senstivity is about 1x10^-10 inch/ (m/s^2).

ELOG V3.1.3-