Update 01 February 2016
News: Step IV and Software
Work in the MICE Hall is focussed on the necessary preparations for the LiH scattering measurements that are planned for the next ISIS User Cycle. It has been decided to adjust the positions of the spectrometer solenoids to account for the measured offset between the magnetic and mechanical axes. Before this work can be undertaken, appropriate bellows to join the spectrometer solenoids to the focus-coil module must be procured.
Many “house-keeping” tasks have been completed (e.g. flushing of the beam-line magnets, DKsoln fridge and compressor servicing, implementation of “pseudo-kinematic” locators for TOF2, KL and EMR …).
Work in R9 is focussed on preparing for the extraction of the liquid-hydrogen vessel so that the leaking seal can be repaired.
A new quench-detection/quench-protection system for the spectrometer solenoids has been devised by the spectrometer-solenoid team. Detailing of the specification of the various components is under way and measurements of critical parameters will be made in Rack Room 2 this week. The spectrometer-solenoid recovery plan continues to be developed.
Software and analysis:
The systematic check-out of the tracker software (Dobbs, Heidt, Hunt, Overton, Uchida) is reaching the end of the first pass through the code. The sign-flip issues in the reconstruction have been addressed and the algorithm check-out from cluster finding, through pattern recognition to the track fit has been completed successfully. Features in the tracker simulation have also been understood and addressed. A. Dobbs is preparing a new release of MAUS that will contain fixes to all known issues. With this release, D. Rajaram will make a consistent reprocessing of all the data that was taken in 2015.
When the data is reprocessed, the alignment constants derived by F. Drielsma will be included. The first attachment shows the status of the alignment of the instrumentation from TOF1, through both the trackers to TOF2, KL and EMR.
The analysis of the data taken on the 7th October 2015 with the end and centre coils of the upstream solenoid at nominal current is progressing. The second attachment (Blackmore) shows the emittance reconstructed from tracks in the upstream tracker plotted in 5 MeV/c momentum bins from 160 MeV/c to 245 MeV/c. The data has been split into two samples of equal size. The first is used to calculate the emittance at the entrance to the upstream tracker (station 5, black solid circles). The second is used to calculate the emittance at the exit of the tracker (station 1, red solid triangles). While more work needs to be done, the plot indicates that we shall be able to make a good measurement of emittance using the single-particle technique.
The xenon scattering data taken just before Christmas is also being analysed. The third attachment shows the scattering angle determined by taking the dot product between the track direction determined in the upstream tracker with that determined downstream (Nugent). The scattering analysis needs to include the alignment corrections outlined above, but, the preliminary analysis indicates that it will be possible to unfold the scattering distribution.
The next video conference will take place on Thursday 04Feb16.