Physics Shift Report¶
Dates: 04-10-2017 - 08-10-2017
Shifter: Christoper Hunt
Run Numbers: 09845 - 09904
Run Number Table¶
|Objective||Analysis Code||Channel||Setting||Run Numbers|
|lH2 Scattering||S14a||Field Off||3-170+M3-Test1||9854, 9856, 9859, 9861, 9882|
|S14b||Field Off||3-200+M3-Test2||9855, 9857, 9858, 9860, 9881|
|S14c||Field Off||3-140+M3-Test3||9862, 9863, 9864, 9865, 9875, 9876, 9877, 9878, 9879, 9880|
|lH2 Emittance Evolution||H30a||2017-02-5||3-140+M3-Test3||9867|
|H30b||2017-02-5||4-140+M3-Test2||9868, 9871, 9873, 9874|
|H31a||2017-02-6||3-140+M3-Test3||9883, 9888, 9893, 9897, 9903|
|H31b||2017-02-6||4-140+M3-Test2||9884, 9885, 9889, 9894, 9898, 9904|
|H31c||2017-02-6||10-140+M3-Test4||9886, 9887, 9890, 9891, 9892, 9895, 9896, 9899, 9900, 9901, 9902|
|Momentum Scan/Alignment||H29a||2017-02-4||3-170+M3-Test1||9845, 9850|
|H29b||2017-02-4||3-200+M3-Test2||9846, 9848, 9849, 9851|
Runs containing a field flip in SSDM2:
09867 - 09874
Elog, CDB, and Reconstruction¶
Elog entries: All ok.
CDB uploaded: All ok.
Online reconstruction: All ok.
Friday 6th Oct.
Suspicious readings from the FC force metres, and a reduced transmission led the experts to believe that SSDM2 was powered in reverse.
Day was spent trying to validate that assumption using reconstructed tracks.
The residual between projected phi-angles and reconstructed phi-angles was used to exmine the data. In theory, if a coil is flipped, the particle track spends some time rotating in the opposite direction than it otherwise would. Therefore the reconstructed phi-angle would differ from the predicted. ( phi = atan2(py, px) )
Previous data sets showed residuals centred very close to zero - indicating that the number of rotations was approximately as expected.
Data from run 09867 showed a notable deviation from zero which was removed when a geometry containing a field flip was introduced. This was more than enough proof for the magnet experts to proceed in flipping the current leads to M2.
- There is a PMT power supply issue in the EMR plane 26. This is known about by the experts so no problem.
- lH2 Geometry within the reconstruction was fixed half way through the Physics Shifter cycle. (Runs 09895-09896) Take care with track extrapolation.
- Noticed that Pion Ref Run 09853 shows a suprisingly well focussed beam at TOF2. This is presumably a fluke of the optics+initial beam parameters?