Cave A beamlines

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Introduction

Cave A is used for atomic physics experiments but as well for irradiation studies of material (with unique possibility to irradiate samples under pressure), biological samples and electronics for space instruments. Beam in Cave A can come directly from SIS-18 or from ESR. Beam from ESR has is usually cooling.

Experiments in Cave A are made usually by atomic physics, APPA Biophysik and APPA SMAT collaborations.

The contact persons for this HTA are: Radek Pleskac, Angela Brauning Demian (atomic physics, usually ESR beams), Michael Scholtz, Christina Trautmann.

The following magnets are inside the cave: GHTAQD21, GHTAQD22 and GHTAMU2. The two quads have bipolar power converters, what is important for tunelling experiments.

"When the atomic physics works, we use these three magnets with two different settings: Parallel beam in cave an focused beam at the AP target point. In this cases the three magnets are used only for focusing the beam on the particle detector after the target and for scanning the different beam charge states resulting after the beam interaction with the target. When the Biophysics group and the material science group are using the cave, the magnets are dismounted and the beam line does not use them. " (email from Angela, 2018.04.03)

Beams

Here are the main properties of beams:

SIS18_TH_HTA_STANDARD

Remark 1: on 2018.03.29 it was decided to take out GHTAEW1 and GHTAEW2 from LSA optics. These are scanning magnets and they do not have calibration curves.

Remark 2: GHTAQD21, GHTAQD22 and GHTAMU2 do not exist in original MIRKO file; they were added by hand to strength file in order to confirm to LSA import. Their position must be determined.

New optics files (20180416) take into account the above two remarks. However this optics features a very large values of vertical beta (almost 30 km!). This is not physical (but this is what we have in LSA for Engineering Run of November 2018).

Twiss parameters on target:

In order to understand this large beta function values, old IBHS settings were checked. They also feature a very large beta function, like this optics for 12C run in July 2016:

SIS18_TH_HTA_LEGACY

It is legacy optics for TH_THA, recovered from front end (MI-program).

Optics functions:

LSA files:

ESR_HTA_STANDARD

This optics has been used for chanelling experiments. LSA files are based on information from Carl and IBHS saves from 2016.

Last IBHS file of 2016: HS-238U_-160530-0603-ES-TT-HTA.DAT

Images:

Cave setup for channeling experiments (Angela, 2016):