SIS18_PION_HADES_STANDARD optics

(return)

This is slow extraction high spill population optics for pion production for HADES experiment.

The development and commissioning of pion beam is described here: NIMA2002_HADES_PionBeam.pdf. The optics has been developed after 2014 run, where high beam intensity was used and therefore high radiation levels were observed (NDosis_Radon_SIS_2014.pdf).

On the following figure the optics (beam envelope) for pion production mode is shown (courtesy S. Ratschow). Blue line shows optics used in 2014 run, while the green one shows optics proposed for 2018 run. The plot was obtained using MIRKO. Pion production target is placed where the beam is focused and after target pion beam is present. The emittance is 1x4 (mm*mrad)2.

The beam phase advance for the new optics is shown below. Because of high gradient of HADQD11 the phase changes very fast nearby target. Horizontal phase reaches about 306 deg and vertical one reaches about 400 degree (as read from the TWISS file).

The horizontal beta function reaches 2145 m inside HADQD11 and vertical one reaches 953 m inside HADQD12:

The files:

Above files have two issues:

1. settings after pion target (for muons) are missing
2. the last file does not conform to LSA import rules yet

The resulting pions have theoretical momentum in a range between 0.4 and 2.4 GeV/c, what corresponds to rigidities between 1.33 and 9.34 Tm. However during the beamtime 2014 only the pions in range between 0.7 and 1.4 GeV/c were used. Selection of momentum of pions for experiment is done by setting the optics after the pion target accordingly.