The beam positions of the SPEAR storage ring

Carman, C.R.; Pellegrin, J.-L.

doi:10.1016/0029-554x(73)90509-0

Cited by 10 publications

(4 citation statements)

References 2 publications

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“…It is necessary to correct the equation of ∆/Σ since we have a slow raster with a large size of˜2 cm. With the assumption of an infinitely long chamber and neglecting the antenna influence on the electric field inside the chamber, the signal from each antenna excited by the beam can be calculated via image charge method ( Fig.8) [9,10] :…”

Section: Bpm Data Analysis and Calibrationmentioning

confidence: 99%

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Beam position reconstruction for the g2p experiment in Hall A at Jefferson lab

Zhu

Allada

Allison

et al. 2016

Nuclear Instruments and Methods in Physics Research Section A:

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Beam-line equipment was upgraded for experiment E08-027 (g2p) in Hall A at Jefferson Lab. Two beam position monitors (BPMs) were necessary to measure the beam position and angle at the target. A new BPM receiver was designed and built to handle the low beam currents (50-100 nA) used for this experiment. Two new super-harps were installed for calibrating the BPMs. In addition to the existing fast raster system, a slow raster system was installed. Before and during the experiment, these new devices were tested and debugged, and their performance was also evaluated. In order to achieve the required accuracy (1-2 mm in position and 1-2 mrad in angle at the target location), the data of the BPMs and harps were carefully analyzed, as well as reconstructing the beam position and angle event by event at the target location. The calculated beam position will be used in the data analysis to accurately determine the kinematics for each event.

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Section: Bpm Data Analysis and Calibrationmentioning

confidence: 99%

“…(a) is the signal with beam, (b) is the pedestal signal without beam (1,2,3). in (a,b) are the raw signal without applying the filter,(4,5,6) are applied a 2 Hz finite-impulse-response filter with 4th order (7,8,9). are averaged with 0.5 s.(1,4,7)are the 1-D histogram of the recorded signal,(2,5,8) are the signal in time domain,(3,6,9) are in frequency domain.…”

mentioning

confidence: 99%

Beam position reconstruction for the g2p experiment in Hall A at Jefferson lab

Zhu

Allada

Allison

et al. 2016

Nuclear Instruments and Methods in Physics Research Section A:

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show abstract

“…It is necessary to correct the equation of ∆/Σ since we have a slow raster with a large size of ~2 cm. With the assumption of an infinitely long chamber and neglecting the antenna influence on the electric field inside the chamber, the signal from each antenna excited by the beam can be calculated via image charge method (figure 5.20) [142,143] :…”

Section: Get Beam Position From Bpmsmentioning

confidence: 99%

A measurement of the proton’s spin structure function g2 at low Q2

Zhu

2015

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JLab E08-027, a measurement of g2p and the longitudinal-transverse (LT) spin polarizability, successfully collected data from March to May, 2012. Nucleon spin structure study has been an active research area, which has attracted a very large effort from both experimentalists and theorists. The spin structure study for the last 2 decades has provided us with many exciting and often surprising results. Recently, new precision results in the low-to-intermediate momentum transfer Q 2 region from JLab have provided extensive information on the nucleon structure in the confinement region and the transition region between asymptotic free to confinement. In particular, the extensive comparisons of experimental results with Chiral Perturbation Theory (the effective theory of QCD at low energy) calculations show general good agreements, but strong disagreement in the case of the neutron LT spin polarizability. This experiment completed the measurements of g p 2 and the LT spin polarizability on the proton in the lowto-intermediate Q 2 region.The experiment used a polarized proton (N H 3 ) target for the first time in Hall A. Scattered electrons were detected by a pair of Hall A high resolution spectrometer (HRS) with a pair of septum magnets. To avoid too much depolarization of the target, beam current was limited to 50-100 nA during the experiment. Since the existing beam current monitors (BCMs), beam position monitors (BPMs) and calibration methods did not work at such a low current range, new BPM and BCM receivers were designed and used for current condition. A pair of super-harps and a tungsten calorimeter were installed to calibrate the BPMs and BCMs. To compensate for the effect of the 2.5/5T transverse magnet field, two chicane dipole magnets were installed. A pair of slow rasters were installed for the first time in Hall A, combining with a pair of fast raster. The standard Hall A DAQ system and the improved high resolution DAQ system were used to record the detector information and the helicity dependent beam information, respectively.In order to achieve the required accuracy of the beam position and angle and reconstruct them event by event at the target location, the data of the BPMs and harps were carefully analyzed. The final uncertainty of BCM after the calibration using the tungsten calorimeter is below 1%, which is important for the asymmetry extraction. Before the acceptance and the dilution factor are available, the models from fitting to the world data were used instead to extract the unpolarized cross section and the dilution factor. The longitudinal and transverse physics asymmetries were extracted and compared with the model, with the study of the radiative correction. The preliminary g 1 and g 2 results were then extracted using the measured asymmetry and the model.

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“…Examples include: 1) electronic spectral analysis of the outputs of distributed inductive or capacitive pickups placed in proximity to the beam [1,2], 2) streak camera or fast photodiode sampling of the spontaneous radiation emitted by the particle bunch [3,4], and 3) Michelson (autocorrelation) interferometry applied to quasicoherent transition or synchrotron radiation emitted by the bunch [5]. Potential drawbacks of 1) and 2) for very short bunches include the limited angular or spectral bandwidths of conventional electronic deflection systems and instrumentation.…”

Section: Introductionmentioning

confidence: 99%

Analysis of a single-shot longitudinal bunch profiling system based on an ultra-short pulse Ti:sapphire laser

Tatchyn

Proceedings of the 1997 Particle Accelerator Conference (Cat. No.97CH36167)

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Recent advances in ultra-short pulse high-power laser technology include the generation of <10 fs pulses at 1 µ wavelengths in the multi-terawatt regime. These parameters, coupled with the high per-pulse energy of the new sources, make possible the consideration of longitudinal bunch profiling schemes capable of accurately registering the longitudinal bunch density in a single shot. In this paper we assess the performance and advantages of a longitudinal bunch profiling system based on multi-photon absorption and fluorescence stimulated by the combined bunch and laser fields in a gaseous medium.

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The beam positions of the SPEAR storage ring

Cited by 10 publications

References 2 publications

Beam position reconstruction for the g2p experiment in Hall A at Jefferson lab

Beam position reconstruction for the g2p experiment in Hall A at Jefferson lab

A measurement of the proton’s spin structure function g2 at low Q2

Analysis of a single-shot longitudinal bunch profiling system based on an ultra-short pulse Ti:sapphire laser

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