MOP012
BNL, Upton, New York, USA
Brookhaven National Laboratory (BNL), Electron-Ion Collider, Upton, New York, USA
The Electron Ion Collider (EIC) is being built at Brookhaven National Laboratory (BNL). Early preliminary design phase efforts are underway. In addition to upgrading the existing RHIC instrumentation for the EIC hadron storage ring, new electron accelerator subsystems that include a 400 MeV Linac, rapid-cycling synchrotron, electron storage ring, and a strong hadron cooling facility will have all new instrumentation systems. The scope of the instrumentation includes devices to measure beam position, loss, current, charge, tune, transverse and longitudinal profiles, emittance, and crabbing angles. A description of the planned instruments and the present design status will be presented.
BNL, Upton, New York, USA
Growing demand on the beam orbit stability requires higher loop gain within the operational bandwidth. Increasing the gain leads to the increase of the unity gain frequency and creates problems with systems stability due to the additional phase shifts caused by the trims (power supplies, eddy currents in vacuum chambers, etc.) and filtering of beam position data. Conventionally employed systems have 20 dB/decade slope near the unity gain providing 90 degrees phase shift which is sufficient for stability. Utilizing one or more lag compensators allows to increase the gain at low frequencies while keeping phase margin acceptable. The paper provides more details on the proposed solution as well as simulations of how the transients will be modified.
BNL, Upton, New York, USA
Top-up operation becomes routine in the light sources. The goal of the top-up operation is to keep the current of the circulating beam stable to avoid variations of the heat load on the beamline optics. It is also considered for the electron-ion collider to maintain the polarization of the electron beam. Frequent re-injection makes measurement of the beam lifetime very difficult if possible. Since, only part of the bunch train is refreshed during the injection cycle then the distribution of the bunch charges in the train has a characteristic saw-tooth distribution. The slope of saw tooth and step in the bunch charge distribution is defined by the lifetime and filling frequency. Both parameters can be used for the measurement. The data for processing can be obtained either from fast current transformer or from the raw ADC signal from beam position monitor. In this paper we present the theoretical considerations as well as experimental data from NSLS-II storage ring.
BNL, Upton, New York, USA
The quadrupole scan is commonly used for measurement of beam emittance. The found dependence of the beam size vs. quadrupole strength is fitted with parabola, which coefficients are used for emittance calculations. The measurement errors can cause substantial variations in the emittance value. Sometimes the fitted parabola has negative minimum value, making impossible emittance calculation. We propose more robust data processing using weighted fit for parabola or modifying the quadrupole scan procedure. The experimental results are presented.
BNL, Upton, New York, USA
Coherent Electron Cooling experiment carried out at RHIC requires small slice emittance of 15 MeV electron beam with high peak current. In this paper we describe the system for slice emittance measurement utilizing transverse deflecting cavity and slit. The image of the beam passing through the slit is used to measure slice intensity and angular divergence. Beam size at slit location is measured using scan of the beam across the slit with trim. The angular kick by the trim is taken into the account during calculations. Data processing and the experimental results are presented.