The Beam Line
The CLEAR facility is hosted by the CLEX experimental area at CERN - building 2010. The CLEAR Beam Line is built on the basis of CALIFES, previously used at CTF3 as Probe Beam injector for testing the CLIC Two Beam Acceleration concept.
On the spectrometer at the end of the CALIFES injector is placed the VESPER (see its official web page): a test stand for irradiation studies.
The layout of the linear accelerator and VESPER is as follows (note that beam travels from right to left):
The 2nd part of the line, which contains most of the experiments:
Legend for the layouts above is:
Various other versions of the drawing above can be found at https://gitlab.cern.ch/CLEAR/clearlayout ; if used in publications please cite K. Sjobak et al, "Status of the CLEAR Electron Beam User Facility at CERN", in proceedings of IPAC2019 (Melbourne), May 2019, MOPTS054, doi:10.18429/JACoW-IPAC2019-MOPTS054, https://cds.cern.ch/record/2695092 .
Technical Drawings of the facility are available on request.
The beam parameters at the end of the linac are summarised in the following table:
|Beam parameter (end of linac)||Value range|
|Energy||60 - 220 MeV|
|Bunch charge||0.01 - 0.5 nC|
|Normalized emittances||3 um for 0.05 nC per bunch
20 um for 0.4 nC per bunch (in both planes)
|Bunch length||~100 um -1.2 mm|
|Relative energy spread||< 0.2 % rms (< 1 MeV FWHM)|
|Repetition rate||1 - 5 Hz (25 Hz with upgrade)|
|Number of micro-bunches in train||1 and more than 100|
|Micro-bunch spacing||1.5 GHz|
Beam line MAD-X Lattice
The MAD-X sequence of the present beam line is available on the official CERN Gitlab Optics Repository.