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Slow extraction from synchrotrons is widely used for delivering hadron beams to many physical experiments as well as hadron cancer therapy based on charged particle deposition on tumors. The extracted beam is also referred to as spill. The temporal uniformity of the slow extracted beam, also known as spill uniformity, is an important indicator of spill quality. A uniform beam intensity throughout the beam spill time is usually required in these physical experiments and hadron cancer therapy. In order to meet the requirements of these applications, the spill uniformity from the accelerator must be improved. In practice, the spill uniformity is degraded due to the influence of various factors, the intensity of the extracted beam fluctuates, forming spill ripple. How to suppress the spill ripple and improve spill uniformity has always been an important research direction in the field of slow extraction from synchrotrons. In order to optimize the spill uniformity, it is first necessary to determine the source of the nonuniformity of the spill, that is, the spill ripple. The spill spectrum plays a key role in analyzing the spill ripple, the conventional spill spectrum analysis method judges the main source of spill ripple through the spectrum amplitude, and the conventional method cannot correctly reflect the influence of the spill ripple with a frequency bandwidth. In this paper, a method for quantitative analysis of the spill spectrum was proposed. According to this method, spill ripples caused by different reasons can be classified, and the contribution of different types of spill ripples to nonuniformity can be quantitatively calculated. The quantitative comparison of the impact of different types of ripples can be realized. This method was applied in the optimization of the spill uniformity at Xi’an 200 MeV proton application facility synchrotron. After analysis, it is found that the main spill ripple of the XiPAF synchrotron came from the magnet power supply ripple and low-frequency ripple. In the experiment, the influences of magnet power supply ripple and low-frequency ripple are suppressed respectively. The influence of the magnet power supply ripple is suppressed by optimizing the spectrum of the RF-KO signal to reduce the particle density near the separatrix. And the low-frequency ripple is suppressed by the feedback control of the amplitude of the RF-KO. After optimization, the spill uniformity of the XiPAF synchrotron is significantly improved, and the standard deviation of the extracted beam intensity divided by the average could reach about 10% at a sample rate of 1.3 kHz.

Cirrhosis caused by viral and alcoholic hepatitis is an essential cause of portal hypertension (PHT). The incidence of PHT complication is directly proportional to portal venous pressure (PVP), and the clinical research of PVP and its hemodynamic indexes is of great significance for deciding the treatment strategy of PHT. Various techniques are currently being developed to decrease portal pressure but hemodynamic side effects may occur. In this article, the hemodynamic indexes of cirrhotic PHT patients were studied to explore the correlation between the index and PVP and to evaluate the clinical value of Doppler ultrasound in measuring PVP in patients with PHT. This was achieved by selecting 90 cirrhotic PHT patients who underwent transjugular intrahepatic portosystemic shunt in our hospital from June 2015 to September 2019. Fifty healthy people who had a physical examination in the hospital in the same period were selected as the control group. The liver hemodynamic parameters of two groups were measured by Doppler ultrasound, and the cirrhotic PHT patients were graded by the Child–Pugh grading method to evaluate the liver function and measure the PVP value. The results showed that both the central portal vein velocity (PVV) and splenic vein velocity (SVV) of the PHT group were lower than those of the control group. Also, the portal vein diameter (PVD), portal venous flow and splenic vein diameter (SVD) were higher than those of the control group (all Ps < 0.05). Among liver function graded PHT patients, the PVD, PVV, SVD and SVV were significantly different (all Ps < 0.05). Furthermore, the PVP of patients with liver function grades A, B and C was 38.9 ± 1.4, 40.6 ± 5.1 and 42.5 ± 4.8 cmH2O, respectively, with a significant difference. It can be concluded from this study that Doppler ultrasound can be used as a tool for clinical assessment of PHT in cirrhosis patients. Doppler ultrasound showed a good prospect in noninvasive detection of PHT in cirrhosis; however, this technique needs application on large sample population study to validate the results.