First BTF Users Workshop – Frascati, 6th and 7th May, 2014
Additional beam-lines for the BTF
Paolo Valente
on behalf of the BTF team
Future interest in BTF lines
 Electrons/positrons:
 LHC experiments upgrades are already using or planning to use the BTF.
 The main feature of the BTF is that the running conditions can be changed
easily, according to the user requests:
 Beam intensity can be tuned down to a Poissonian distribution with arbitrary
average
 Energy can be selected with good accuracy (1%) down to <50 MeV
 Beam spot can be squeezed to 2 mm (in the horizontal coordinate, even smaller in
the vertical one) and carefully controlled and monitored
 Divergence is at the level of 1-2 mrad (acceptable even tough not optimal for
tracking applications)
 There is a continuous support by the BTF staff for logistics, DAQ, beam setting up
and tuning, diagnostics, beam parameters monitoring
 Can cover shutdown periods of CERN and other beams

There are also limitations:
 The maximum energy (750 MeV, 510 MeV in parasitic mode)
 The multiple scattering/showering of electrons

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Constant interest from many non-LHC experiments (ILC, CLAS12,
BES-III, MEG-2, UA9, FAMU, …)
First BTF Users Workshop – Frascati, 6th and 7th May, 2014
Future interest in BTF lines
 Low energy Electrons/positrons/photons:
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Low energy positrons (and photons) are interesting especially for astro-particle
and satellite esperiments
Limadou, Gamma-400, Juno already have made requests
Useful in general for calibration purposes (crystal calorimeters typically) for the
range of energy of few MeV which is not accessible by radio-active sources
 Tagged photons:
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The use of the photon tagging has been limited, mainly due to the fact that the
tagging detectors are not in the focal plane of the present dipole magnet
(details in section 6 of
http://www.lnf.infn.it/sis/preprint/pdf/getfile.php?filename=INFN-14-06-LNF.pdf)
Groups working on crystal calorimeters have shown interest in a tagged photon
beam (e.g. Belle-2)
Collimating and selecting electrons radiating Bremsstrahlung photons could
produce an interesting low energy electron/positron beam
First BTF Users Workshop – Frascati, 6th and 7th May, 2014
Present layout
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First BTF Users Workshop – Frascati, 6th and 7th May, 2014
Minimal upgrade
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First BTF Users Workshop – Frascati, 6th and 7th May, 2014
Aside: improve shielding
BTF hall, external
Additional shielding
(concrete blocks)
BTF hall, internal
• Limitation on full intensity operations due to gap in the additional shielding walls of
the hall
• Crucial for neutron production, e.m. interaction tests (e.g. microwave, fluorescence
production by electrons)
• Also important for intermediate intensity long-term operations
• Applications: neutron production, high rate tests (with long beam pulse)
• Proposal: (partially) cover the area with a ceiling made of concrete beams ≈1 m
depth
First BTF Users Workshop – Frascati, 6th and 7th May, 2014
A possible solution
Concrete roof, 1 m depth
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First BTF Users Workshop – Frascati, 6th and 7th May, 2014
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First BTF Users Workshop – Frascati, 6th and 7th May, 2014
A possible alternative
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First BTF Users Workshop – Frascati, 6th and 7th May, 2014
Proposal to AIDA-2 for the BTF
Present
layout
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First BTF Users Workshop – Frascati, 6th and 7th May, 2014
What is needed
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Pulsed magnet + power supply
Beam pipe, vacuum, pumps, windows
Controls, diagnostics
Alignment, dismounting, mounting
First BTF Users Workshop – Frascati, 6th and 7th May, 2014