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Run-17 Alignment

Updated on Wed, 2020-05-13 15:47. Originally created by iraklic on 2020-05-05 10:20.

 Prelude:

Spin group noticed a very large discrepancy between differently charged tracks, this raised questions about space charge and alignment (some other things too).
The alignment used in Run-17 was one done for Run-14. HFT addition and removal could have affected the alignment. So, we decided to check it. Below are results.

Inner sector vs. outer sector alignment was checked baased on about 3M cosmic tracks (Reverse full field). There are plenty of cosmics luckily:

This shows that inner and outer sector are aligned well enough (within ~150 microns).

Next I checked the alignment of entire supersectors based on the reconstructed vertex. This is based on following reconstruction:

st_W_18054003_raw_3500004.MuDst.root
st_W_18058014_raw_4500002.MuDst.root
st_W_18063022_raw_2000002.MuDst.root
st_W_18065067_raw_5000053.MuDst.root
st_W_18070075_raw_1500003.MuDst.root
st_W_18077002_raw_4000056.MuDst.root
st_W_18080026_raw_2000006.MuDst.root
st_W_18082002_raw_5500001.MuDst.root
st_W_18085013_raw_3500007.MuDst.root
st_W_18089018_raw_3500008.MuDst.root

Here are the results:


RED - LOCAL X
BLUE - LOCAL Y
BLACK - LOCAL Z

Sector 20 is understandably bad (because it was missing a huge chunk in Run-17) but it looks like this may need some attention. 

 

UPDATE: at this point Gene noticed that the chain option used in reco for the Space Charge calibration was wrong. I did reconstruction of small sample with the correct option. The results is below. There is some room for improvement but this is now not as drastic as it seemed.

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