HHD beamline

(return)

Introduction

HHD is a beam dump. This is the shortest of the HEST beam lines. Currently (2018) the dump beam line goes through GTS3MU1 magnet, which is a slow magnet. This makes a parallel operation between FRS and HHD impossible. In addition the dumped beam goes through the front part of FRS focusing system, the target area and even a beam window in front of the target area which separates FRS vacuum from SIS18. Because of these issues a new solution has been proposed. The new dump line uses the fast switching magnet (current GTS1MU1, which will be replaced by a new magnet in 2019) moved downstream. In addition another dipole (matching), two normal quadrupoles and one short are needed. The whole beam dump will have to be slightly rotated as the beam will arrive from a different angle. Total cost of the project is estimated to be ~ 3 million euros.

Both, the current and the proposed solution, are illustrated on the plot below. Beware: because of rather small deflection angle of the old GTS1MU1 a shift of GTE2QT11 (or 13?) quadrupole is also required (new position is on the plot), otherwise one cannot accomodate the new vacuum chamber. More information.

During the long shutdown 2017-2018 the FRS team added a new vertical steerer called GTS2KY1, in order to be better prepared for effect of ground sinking due to FAIR construction works.

Beams

All types of beams in fast and slow extraction are accepted. This beam pattern is always resident.

Optics

Two optics for this beamline are available: optics from MIRKO svn repositories) called SIS18_HHD_STANDARD, and optics from Magnet Initialization files, called SIS18_HHD_LEGACY.

SIS18_HHD_STANDARD

Beam envelope modelled with MIRKO is shown below.

Beam envelope obtained with MAD-X is very similar:

Beta functions obtained with MAD-X:

New, November 14, 2017. Comparison MIRKO/MADX:

SIS18_HHD_LEGACY

Legacy optics features higher beta functions.

Elements

This beamline contains the following main magnets:

Photos

On the photo below there is the end of the beamline together with the dump.