PARTICLE PRODUCTION OF A GRAPHITE TARGET SYSTEM FOR THE INTENSITY FRONTIER* X. Ding, † UCLA, Los Angeles, CA 90095, USA H.G. Kirk, Brookhaven National Laboratory, Upton, NY 11973, USA K.T. McDonald, Princeton University, Princeton, NJ 08544, USA Abstract A solid graphite target system is considered for an intense muon and/or neutrino source in support of physics at the intensity frontier. We previously optimized the geometric parameters of the beam and target to maximize particle production at low energies by incoming protons with kinetic energy of 6.75 GeV and an rms geometric emittance of 5 mm-mrad using the MARS15(2014) code. In this study, we ran MARS15 with ROOT-based geometry and also considered a mercury-jet target as an upgrade option. The optimization was extended to focused proton beams with transverse emittances from 5 to 50 mm-mrad, showing that the particle production decreases slowly with increasing emittance. We also studied beam-dump configurations to suppress the rate of undesirable high-energy secondary particles in the beam. INTRODUCTION Neutrino-physics and muon-physics at the intensity frontier require the greatest possible beam intensities of neutrinos and muons. The target scenario for the present study is to use a 6.75-GeV proton driver with beam power of 1 MW [1] interacting with a graphite target in the so- called 20to2T5m4PDL target system configuration, as shown in Fig. 1. Figure 1: Layout of the 20to2T5m4PDL Target System configuration. Figure 2 shows that the axial magnetic field for configuration 20to2T5m4PDL tapers adiabatically over 5 m from 20 T around the target to 2 T in the rest of Front End [2]. The inner radius of superconducting coils (SC) in the region surrounding the graphite target is 120 cm to permit sufficient internal tungsten shielding for a 10-year operational lifetime of the SC coils against radiation damage [3]. The first 50 m of the magnetic channel of the Front End is sketched in Fig. 3. Figure 2: Axial magnetic field of the 20to2T5m4PDL (red dots) and 15to2T5m4PDL (blue dots) Front-End channels. The center of the target is at z = 0. Figure 3: Schematic of the 20to2T5m4PDL Target System configuration, for -2 < z < 50 m. The graphite-target, and graphite-beam-dump, rods are inside a double-walled stainless-steel containment vessel, with downstream Be windows, shown at the right of Fig. 1. These rods are radiation cooled, and the containment vessel is cooled by He-gas flow between its double walls. The outer cylinder extends over -46 < z < 170 cm, with outer radius r = 15 cm. The inner cylinder extends over - 45 < z < 169 cm, with inner radius r = 14 cm. The ____________________________________________ *Work supported in part by US DOE Contract NO. DE- AC02-98CH110886. † xding@bnl.gov