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RESEARCH PRODUCT

Design and Operation of a Windowless Gas Target Internal to a Solenoidal Magnet for Use with a Megawatt Electron Beam

P. MoranR. KazimiP. H. FisherJan C. BernauerY. F. WangC. TschalärKevin JordanM. GarçonM. MccaughanJ. KelseyIvica FriščićE. IhloffG. RandallD. HasellS. FriersonCarlos Hernandez-garciaJames ColemanRichard G. MilnerJ. BalewskiMichael KohlShukui ZhangS. LeeJ. NazeerD. PalumboC. VogelJoseph GramesRicardo AlarconS.v. BensonM. PoelkerJames BoyceR. CorlissJ. BessuilleS. AulenbacherA. LiyanageC.s. EpsteinS. G. SteadmanChris TennantDavid DouglasR. JohnstonC. Vidal

subject

Nuclear and High Energy PhysicsPhysics - Instrumentation and DetectorsOrders of magnitude (temperature)Windowless gas targetNuclear engineeringDarkLightFOS: Physical sciences[PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex]01 natural sciences7. Clean energyCOMSOLFree molecular flow0103 physical sciencesCalibration[PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det]Nuclear Experiment (nucl-ex)010306 general physicsInstrumentationNuclear ExperimentPhysicsSolenoidal vector field010308 nuclear & particles physicsLaminar flowDark photonInstrumentation and Detectors (physics.ins-det)BeamlineMagnetCathode ray

description

A windowless hydrogen gas target of nominal thickness $10^{19}$ cm$^{-2}$ is an essential component of the DarkLight experiment, which is designed to utilize the megawatt electron beam at an Energy Recovery Linac (ERL). The design of such a target is challenging because the pressure drops by many orders of magnitude between the central, high-density section of the target and the surrounding beamline, resulting in laminar, transitional, and finally molecular flow regimes. The target system was assembled and operated at Jefferson Lab's Low Energy Recirculator Facility (LERF) in 2016, and subsequently underwent several revisions and calibration tests at MIT Bates in 2017. The system at dynamic equilibrium was simulated in COMSOL to provide a better understanding of its optimal operation at other working points. We have determined that a windowless gas target with sufficiently high density for DarkLight's experimental needs is feasible in an ERL environment.

10.1016/j.nima.2019.05.071http://arxiv.org/abs/1903.02648