SIS18_TH_HTP_STANDARD optics

(return)

The optics files below:

• MIRKO twiss and sequence - as exported from MIRKO 2017, using new format of MIRKO files (from svn:bbe/Lattics/trunk/HEBT/gsi_beamlines)
• MADX - sequence - based on MIRKO sequence with manual corrections
• MADX twiss - executing MADX sequence
• LSA files - the best knowledge (from MIRKO or MADX twiss, those are from MIRKO)

This optics has been used for tests during dry runs 1 (October 23rd-25th, 2017), 2 and 3.

Preliminary optics image (beta functions in MIRKO):

The same optics translated to MADX:

The the purpose of the minimum of the beta function at 125 meters is location of a stripper foil in this place (GTH4DK3)

Comparison the two results (October 19th, 2017):

Comment: the difference between MIRKO and MADX is not understood for the moment. The positions of the elements agree (negative drifts present in MIRKO files are correctly converted to MADX sequence). The discrepancy exists also if centre flag is used in MADX twiss command. Interestingly the discrepancy starts after the first active switching dipole, therefore maybe SBENDs are treated differently by MADX and by MIRKO. Interestingly, the are with the largest difference between the two programs is also the most sensitive to misalingments of beam elements:

Beam commissioning June 2018

• Beam was brought to GHHTDF7V (scintillating screen with Cupid digital readout) on Friday June 29, but no signals were seen in HTP that day. Only next day the beam image was registered:

Beam commissioning July 2018

• On July 5th/6th the following beam was setup: 48Ca10+, U12, S01, 300 MeV/u, fast extraction. The following setup was used: 2018-07-05_23-44-36_SIS18_HTP_FAST_20180702.C1.txt. With this setup there was a significant loss at extraction, ie. the beam coming into HEST was loosing already about factor 5 intensity. Fast extraction settings to be optimized. One of the main issues during the beam setup was a closed valve GTH4VV2T. It was opened manually.