HERA Status and Upgrade Plans

Willeke, F.

Report/Contribution to a conference proceedings

PUBDB-2016-02854

HERA Status and Upgrade Plans

Willeke, F. (Corresponding author)

1997

17th IEEE Particle Accelerator Conference, PAC 97, Vancouver, USA, 12 May 1997 - 16 May 1997 65 pp. (1997) [10.3204/PUBDB-2016-02854]

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Report No.: DESY-M-97-10S

Abstract: The HERA electron-proton collider at Hamburg Germany, designed for collisions of 820 GeV protons with 30 GeV electrons is now in its 6th year of operation. It delivers luminosity for the colliding beam detectors H1 and ZEUS and longitudinally polarized positrons for the internal target experiment HERMES. HERA is operated close to the design luminosity with peak values of 1.2 $\times$ 10$^{31}$ cm$^{−2}$ sec$^{−1}$. While the beam currents still fall short of expectations, the luminosity was increased by focusing the beams very tightly at the interaction points at the expense of using up most of the margins on aperture, chromaticity and beam-beam tuneshift. In 1996, an integrated luminosity of $\int$ $\mathcal{Ldt}$ = 17.2$\mathcal{pb}^{−1}$ has been delivered. Despite the strong beam-beam interactions, the degree of longitudinal polarization of the positron beam is, with (50-60)%, larger than expected. Despite the good results of HERA, more luminosity is needed for the physics program in the next decade. Preparations are underway to increase the luminosity by rebuilding the low-$\beta$ insertions. With unconventional new types of magnets, it seems to be possible to increase the luminosity substantially. The expected value is $\mathcal{L}_{peak}$ =7.5 $\times$ 10$^{31}$cm$^{−2}$sec$^{−1}$ which is five times larger than the design value.

Keyword(s): talk: Vancouver 1997/05/12 ; electron p: storage ring ; positron p: storage ring ; performance ; positron: polarized beam ; luminosity: upgrade ; vacuum system: pressure ; DESY HERA Stor