Upgrading RHIC for higher luminosity

Abstract While RHIC has only just startedrunniug for its heavy ion physics progr~in the fiist run last snmmeq we achieved 100/0of the design luminosity.In this paper we discuss plans for increasingthe luminosi~by a factor of 35 beyond the nominal design. A factor of 4 should be straightforwardby doubling the number of bunches per ring and squeezing the P* horn 2 to 1 m at selected interactionpoints.An additionalf%tor of 8 to 10 could be possible by using electron cooling to counteractintrabeam scatteringandreduce emittancesof the beams

Upgrading RHIC for higher luminosity

Abstract While RHIC has only just startedrunniug for its heavy ion physics progr~in the fiist run last snmmeq we achieved 100/0of the design luminosity.In this paper we discuss plans for increasingthe luminosi~by a factor of 35 beyond the nominal design. A factor of 4 should be straightforwardby doubling the number of bunches per ring and squeezing the P* horn 2 to 1 m at selected interactionpoints.An additionalf%tor of 8 to 10 could be possible by using electron cooling to counteractintrabeam scatteringandreduce emittancesof the beams

Proof-of-Principle Experiment for FEL-Based Coherent Electron Cooling,”

Abstract Coherent electron cooling (CEC) has a potential to significantly boost luminosity of high-energy, highintensity hadron-hadron and electron-hadron colliders. In a CEC system, a hadron beam interacts with a cooling electron beam. A perturbation of the electron density caused by ions is amplified and fed back to the ions to reduce the energy spread and the emittance of the ion beam. To demonstrate the feasibility of CEC we propose a proof-of-principle experiment at RHIC using SRF linac. In this paper, we describe the setup for CeC installed into one of RHIC's interaction regions. We present results of analytical estimates and results of initial simulations of cooling a gold-ion beam at 40 GeV/u energy via CeC

An Experimental Proposal to Study Heavy-Ion Cooling in the AGS Due to Beam Gas or the Intrabeam Scattering DISCLAIMER EXPERIMENTAL PROPOSAL TO STUDY HEAVY-ION COOLING IN THE AGS DUE TO BEAM GAS OR THE INTRABEAM SCATTERING *

Abstract Low emittance of not-fully-stripped gold (Z=79) Auc77 Helium-like ion beams from the AGS (Alternating Gradient Synchrotron) injector to the Relativistic Heavy Ion Collider (RHIC) could be attributed to the cooling phenomenon due to inelastic intrabeam scattering [ 1,2] or due to electron de-excitations from collisions with the residual gas [3]. The low emittance gold beams have always been observed at injection in the Relativistic Heavy Ion Collider (RHIC). There have been previous attempts to attribute the low emittance to a cooling due to the exchange of energy between ions during the inelastic intrabeam scattering. The Fano-Lichten theory [4] of electron promotion might be applied during inelastic collisions between helium like gold ions in the AGS. The two K-shell electrons in gold could get promoted if the ions reach the critical distance of the closest approach during intra-beam scattering or collisions with the residual gas. During collisions if the ion energy is large enough, a quasi-molecule could be formed, and electron excitation could occur. During de-excitations of electrons, photons are emitted and a loss of total bunch energy could occur. This would lead to smaller beam size. We propose to inject gold ions with two missing electrons into RHIC, at injection energy, and study the beam behavior with bunched and de-bunched beam, varying the RF voltage and the beam intensity. If the "cooling" is observed additional X-ray detectors could be installed to observe emitted photons

BROOldiAVEN NATIO;NAL LABORATORY MeRHIC -staging approach to eRHIe DISCLAIMER MERRIe -STAGING APPROACH TO ERHIC

Abstract Design of a medium energy electron-ion collider (MeRHIC) is llilder development at the ColliderAccelerator Department at BNL. The design envisions construction of a 4 GeV electron accelerator in a local area inside and near the RHIC tunnel. Electrons will be produced by a polarized electron source and accelerated in energy recovery linacs. Collisions of the electron beam with 100 GeV/u heavy ions or with 250 GeV polarized protons win be arranged in the existing IP2 interaction region of RHIC. The luminosity of electron-proton collisions at the 10 32 cm-2 s-1 level will be achieved with 50 rnA CW electron current and presently available proton beam parameters. Efficient proton beam cooling at collision energy may bring the luminosity to 10 33 cm-2S-1 . An important feature ofMeRHIC is that it serves as a first stage of eRHIC, a future electron-ion collider at BNL with both higher luminosity and energy reach. The majority of MeRHIC accelerator components will be used in eRHIC