Tower 0 Alignment Post-Mortem Meeting

Oct. 26, 2004


  • Participants-  David Rich, Robert Ruland, Martin Nordby, Arthur Scholz, Persis Drell (short time)


  • I/F hardware (nytemp)-  Issue was that Nytemp patch caused excessive running torque.  Corrective actions assigned to Arthur to ensure that this does not recur.  Plan calls for inspection of threads and “run-in” of nytemp patch on both sides of each flight stud.


  • Tower Baseplate stability-  Issue with Tower 0 alignment was baseplate for deformed (slightly) due to incorrect “dither” of  4th Grid (location #5)  I/F hardware installation.  This causes stresses to be induced in Flexures and bottom tray.


Action- Martin will coordinate analysis with John Ku to determine acceptable out of plane condition.  Follow-up action Martin & Arthur (if req’d)- develop proposed method to compensate (shim?) to ensure that out of plane condition is not exceeded.   


  • Tower 0 Align Summary Report (all with respect to Tower coord system)

1)     Height to top of top tray

2)     Height to top edge of corner mount bracket (measured during +z up)

3)     Height to bottom edge of sidewall

4)     Height to bottom of flexures

5)     Include max and min dimensions for line items

6)     Provide text description for line items and include sign convention and figures if required.



Note:  The FIRST alignment summary report is generated as follows:

1-     The raw data is recorded and stored (in a text file) on the CMM in Pisa.

2-     There is a CGI webpage on the SLAC web server.

3-     CMM raw measurement data (pts) and David Tackes CMM report is down loaded to a memory stick (sneaker net).

4-     INFN uploads measured data to INFN database.  This is a raw ASCII text file for data storage and CMM report.

5-     Raw data File is uploaded to the CMM data summary tool (located on the SLAC web server).  This is performed for every tower.  Tower summary alignment report is generated for each tower.

6-     A copy of the tower alignment summary sheet (processed readable data) shall be uploaded to the INFN data base.


The SECOND alignment summary report shall be generated after completion of the “right-side-up” tower CMM measurements.  The steps are the same as above, but this includes tower top, Corner Mount Bracket, Base Plate, and reflector ball fiducialization data.  Also include duplicate data on SCS and TCS offsets for comparison between runs.


ACTION—update scripts for programs 1, 3, and 4 to include raw data text file output for summary data processing at SLAC


Action- Arthur to place updated tower alignment summary template onto the SLAC web server.


Action-  Arthur to create a link from the tracker web page to the SLAC web server for alignment data.



  • Alignment Software (from David Tackes)-  Peter A. received a CD of the five alignment programs written by David Tackes.


1)     Place softcopy of alignment programs on LATDOCs.  (Qty. 5 programs)

2)     Each program will have two files on LATDOCs (ASCII & Program format)

(combine the latdoc & description if file name)

3)     Burn multiple copies of files on CDs

4)     Distribute copies to

a.      Robert Ruland

b.     A. Scholz (working copy and master)


Action-  Discuss impact to schedule if Tower  alignment does not complete on schedule (SLAC team have plans to spend Thanksgiving with their families!  (Robert & Persis)