I wanted to verify the positions of the beamline elements before everything goes to the machine.
To make it easy to check I included the relevant drawing and compute the distance between the effective field boundaries of the quad and the tagger dipole. Just as a summary the tagger dipole upstream effective field boundary is moved downstream from its original position by 19.22cm. The distance between the quad and the tagger is unchanged so the quad also moved by 19.22cm. The goniometer did not move.
Below is a cut out of the relevant drawing.
The distance between the diamond and the effective field boundary is now 3.192m so the diamond has remained fixed and the tagger has moved 19.2cm downstream. This accounts for the fact that we no longer have a gap between two dipoles and therefore can move the start of the field a bit downstream.
The distance from the middle of the quad to the effective field boundary is:
(319.22 - 83.90)= 235.32cm
The distance from the downstream end of the quad to the effective field boundary is
235.32 - (31.26/2)= 219.69 cm where 31.26 is the effective length of the quad.
The numbers Yang gave me for the design report was a distance of 220cm between the effective field boundaries of the Quad and the tagger.
This implies the quad has been moved with the tagger as we wanted. This will give a bit more space around the quad to work
I believe the drawing is correct and that it can be sent to the machine to put in their layout of the tagger hall. I will do so tomorrow evening.
If you think that this is not correct then send me a mail and let me know. Jim
