638
K. Hübner et al.
10.5.2.3 Hadron Beam Collimation
In lepton-hadron collisions with stong beam-beam interaction, the hadron beam
will develop tails in the tranverse particle distribution. The controlled removal of
these halo-particles is very important for low detector background and efficient data
taking.
A sophisticated collimation system and collimator optimization scheme was
implemented in HERA. It consisted of two stages of collimation, with one single
primary collimator per oscillation plane and two secondary collimators per plane. A
detailed and fully automated collimator adjustment procedure was developed which
provided in general good background conditions routinely.
The HERA collimation system and its operational optimization techniques are
being carried over to the eRHIC design version of the EIC.
Furthermore, high energy proton operation with the HERA-B [179] fixed target
in HERA, revealed that the wire target could be integrated in the existing collimator
system. It consitituted an excellent beam-edge spoiler target which significantly
increased the efficiency of the two stage collimation system and led to a significant
reduction of particle background in the detectors H1 and ZEUS.
Early simulations of halo particle backgrounds in HERA showed clearly, that the
halo must be removed far away from the detectors and local shields or masks will
only aggravate the background conditions for the colliding beam detectors [180].
Experience with HERA collimation system have been taken into account in the
elaborated LHC collimation system and are an important input for the design of the
collimation system of eRHIC.
10.5.2.4 Spin Polarization of the HERA Electron Beam
The good performance of the HERA electron spin in colliding beam operations at
the North and the South interaction points with three pairs of spin rotators in the
North, South, and East straight sections which provided a polarization of ≥50%
[181] was vital for the HERMES experiment [182] and augmented the physics
program of the H1 and ZEUS detectors [183]. This performance was achieved with
uncompensated detector solenoids in the North (H1), South (ZEUS) interaction
reagions. The spin tuning procedures developed for HERA which included the
system of harmonic bumps, and spin-matching of the straigth sections between the
rotator pairs, as well as the electron beam working point near the integer resonance
were important factors in this success.
The HERA experience constitutes an important reference point for designing the
EIC for high electron spin polarization. Spin physics is an important part of the EIC
physics program. Collisions between highly polarized electron and Hadron beams
with all combination of spin helicities enable an this physics program.
The spin matching techniques and the scheme of orbit optimization with
harmonic bumps which contributed to the success of the HERA spin program, are
being carried over to the eRHIC design to enable operation with highly polarized
K. Hübner et al.
10.5.2.3 Hadron Beam Collimation
In lepton-hadron collisions with stong beam-beam interaction, the hadron beam
will develop tails in the tranverse particle distribution. The controlled removal of
these halo-particles is very important for low detector background and efficient data
taking.
A sophisticated collimation system and collimator optimization scheme was
implemented in HERA. It consisted of two stages of collimation, with one single
primary collimator per oscillation plane and two secondary collimators per plane. A
detailed and fully automated collimator adjustment procedure was developed which
provided in general good background conditions routinely.
The HERA collimation system and its operational optimization techniques are
being carried over to the eRHIC design version of the EIC.
Furthermore, high energy proton operation with the HERA-B [179] fixed target
in HERA, revealed that the wire target could be integrated in the existing collimator
system. It consitituted an excellent beam-edge spoiler target which significantly
increased the efficiency of the two stage collimation system and led to a significant
reduction of particle background in the detectors H1 and ZEUS.
Early simulations of halo particle backgrounds in HERA showed clearly, that the
halo must be removed far away from the detectors and local shields or masks will
only aggravate the background conditions for the colliding beam detectors [180].
Experience with HERA collimation system have been taken into account in the
elaborated LHC collimation system and are an important input for the design of the
collimation system of eRHIC.
10.5.2.4 Spin Polarization of the HERA Electron Beam
The good performance of the HERA electron spin in colliding beam operations at
the North and the South interaction points with three pairs of spin rotators in the
North, South, and East straight sections which provided a polarization of ≥50%
[181] was vital for the HERMES experiment [182] and augmented the physics
program of the H1 and ZEUS detectors [183]. This performance was achieved with
uncompensated detector solenoids in the North (H1), South (ZEUS) interaction
reagions. The spin tuning procedures developed for HERA which included the
system of harmonic bumps, and spin-matching of the straigth sections between the
rotator pairs, as well as the electron beam working point near the integer resonance
were important factors in this success.
The HERA experience constitutes an important reference point for designing the
EIC for high electron spin polarization. Spin physics is an important part of the EIC
physics program. Collisions between highly polarized electron and Hadron beams
with all combination of spin helicities enable an this physics program.
The spin matching techniques and the scheme of orbit optimization with
harmonic bumps which contributed to the success of the HERA spin program, are
being carried over to the eRHIC design to enable operation with highly polarized