Design and experiments of 65 T high field pulsed magnet

The basic process of re-ionization loss was studied. In the drift duct there are three processes leading to re-ionization loss: the collision of neutral beam particles with the molecules of background gas, similar collisions with released molecules from the inner wall of the drift duct and the ferret-collisions among particles with different energy of the neutral beam. Mathematical models have been developed and taking EAST-NBI parameters as an example, the re-ionization loss was obtained within these models. The result indicated that in the early stage of the neutral beam injector operation the released gas was quite abundant. The amount of re-ionization loss owing to the released gas can be as high as 60%. In the case of a long-time operation of the neutral beam injector, the total re-ionization loss decreases from 13.7% to 5.7%. Then the reionization loss originating mainly from the collisions between particles of the neutral beam and the background molecules is dominant, covering about 92% of the total re-ionization loss. The drift duct pressure was the decisive factor for neutral beam re-ionization loss.

Section: Re-ionization Loss Resulting From Collisions With Background...mentioning

confidence: 99%

“…In this article three of the basic processes of re-ionization loss are discussed and the corresponding mathematical models are developed. Taking a hydrogen neutral beam with the EAST-NBI engineering parameters as an example [3], the re-ionization loss will be derived within these mathematical models.…”

Section: Introductionmentioning

confidence: 99%

Modeling process of the neutral beam re-ionization loss

Lizhen¹,

Hu²,

Yuan-Lai³

et al. 2010

“…1 shows, the four electrodes of a HLS typical BPM are 90 degrees away from each other. By ignoring the influence of bunch size, the electrode signal of this type of BPM can be represented by [3]…”

Section: Derivation Of New Expressionmentioning

confidence: 99%

A new measurement method for electrode gain in an orthogonally symmetric beam position monitor

Zou¹,

Wu²,

Yang³

et al. 2014

The new beam position monitor (BPM) system of the injector at the upgrade project of Hefei Light Source (HLS II) has 19 stripline beam position monitors. Most consist of four orthogonal symmetric stripline electrodes. The differences in electronic gain and mismachining tolerance can cause the change of the beam response of the BPM electrodes. This variation will couple the two measured horizontal positions in order to bring the measuring error. To alleviate this effect, a new technique to measure the relative response of the four electrodes has been developed. It is irrelevant to the beam charge and the related coefficient can be theoretical calculated. The effect of electrodes coupling on this technique is analyzed. The calibration data is used to fit the gain for all 19 injector beam position monitors. The results show the standard deviation of the distribution of measured gains is about 5%.

“…The synchronization precision is about 1 ns and the timeresolved capability of the system can reach 2 ns. A sampling frequency of 12-20 point/mm helps to obtain any minute changes throughout the duration of the pulse [2][3][4].…”

Section: Introductionmentioning

confidence: 99%

Time-resolved energy spectrum measurement of a linear induction accelerator with the magnetic analyzer

Wang¹,

Jiang²,

Gao³

et al. 2015

We recently set up a time-resolved optical beam diagnostic system. Using this system, we measured the high current electron beam energy in the accelerator under construction. This paper introduces the principle of the diagnostic system, describes the setup, and shows the results. A bending beam line was designed using an existing magnetic analyzer with a 300 mm-bending radius and a 60° bending angle at hard-edge approximation. Calculations show that the magnitude of the beam energy is about 18 MeV, and the energy spread is within 2%. Our results agree well with the initial estimates deduced from the diode voltage approach.