116531868
Status, new development and upgrading program at HIRFL
The operation status and new development including the accelerator and experimental stations of HIRFL facility in the last years, and the upgrading program for the next five years are presented. The new completed radioactive beam line RIBLL, the new axial injection system and the new central region for the injector, the ECR ion source development and the new frame of control system are given in some details. The new project CSR is also presented with its main parameters. A upgrading program is under studying to meet the requirement of RIBLL and CSR towards radioactive beam researches.
105752539
The preliminary explanation of a new working model on 10GHz ECR2 source
A new working model and a new magnetic field configuration were employed on the 10GHz ECR2 source of the heavy ion research facility in Lanzhou(HIRFL). That resulted in an obvious enhancement of beam currents of ECR2 ion source, the beam current of Ar9+ increase from 125 e mu A to 320 e mu A, for Ar11+ ion beam increase from 40 e mu A to 80 e mu A. In this paper, primary analysis and explanation of this working model is presented, we will also discuss the action of low energy electrons in ECR plasma and get an important conclusion, which the low energy electrons injection is more effective in the extraction region of ECR ion sources.
219179959
COMMISSIONING OF IMP 14.5GHZ ECR ION SOURCE
A 14.5 GHz.~ew. ECR ion source has been designed and constructed for the upgraded injection beam line of HIRF1.. SFC(Heavy Ion ~esearch FaCility m Lanzhou, Sector Focus Cyclotron) so that eventually two ECR ion sources could be available on the line. The new ECR Ion source has a compact struClUre with a high magnetic mirror ratio and a long chamber. The maximum axial magnetic field on the axis is around 1.5Tesla and the bexapole field on the chamber wall is I.OTesla. The ion source is being tested on the test bench. The preliminary results are typically 100 eJ1A of 0 7+, 160 eJ1A of Arll+ and 50 eJ1A of Xe26+. The design points, characteristics and commissioning are presented .
61057086
The BEPC control system upgraded
The upgrade of the BEPC control system has been finished one year ahead of the schedule and new system was put into use in October, 1994. The upgraded system adopts a distribution architecture based on DECnet. The workstations are used as console to replace the old hardware console, the new VAX computers carry out control jobs. Some dedicated adapters have been eliminated. Up to now, the new BEPC control system has been running safely and reliably for five months. The system upgrading is crowned success. What we have been finished is presented in this paper.
2618144
Looking for Cosmological Alfven Waves in WMAP Data
A primordial cosmological magnetic field induces and supports vorticity or Alfven waves, which in turn generate cosmic microwave background (CMB) anisotropies. A homogeneous primordial magnetic field with fixed direction induces correlations between the $a_{l-1,m}$ and $a_{l+1,m}$ multipole coefficients of the CMB temperature anisotropy field. We discuss the constraints that can be placed on the strength of such a primordial magnetic field using CMB anisotropy data from the WMAP experiment. We place 3 $\sigma$ upper limits on the strength of the magnetic field of $B < 15$ nG for vector perturbation spectral index $n=-5$ and $B<1.7$ nG for $n=-7$.
55936689
A MONITORING SYSTEM FOR CSR POWER SUPPLY
This article elaborated the monitoring system which has applied in the CSR power supply. This system is composed of the hardware and the software. The hardware is composed of PS6040-PXI-18 PXI engine case +PXI-3800 the master controller +PXI-6133 the ADC card. The software uses NI Corporation's LABVIEW to carry on the data demonstration and the analysis. This monitoring system in the CSR debugging, in the acceptance and the running has played the influential role. At the same time, it provided the data for the physical person. This monitoring system has run four years in the CSR. OVERVIEW CSR, a new ion Cooler-Storage-Ring (CSR) project, is the post-acceleration system of the Heavy Ion Research Facility in Lanzhou (HIRFL). Figure 1 show an Overall Layout of HIRFL-CSR. CSR is a multi-purpose CSR system that consists of a main ring (CSRm), an experimental ring (CSRe), and a radioactive beam line (RIBLL II) to connect the two rings. The two existing cyclotrons SFC (K = 69) and SSC (K = 450) of the HIRFL will be used as its injector system. The heavy ion beams with the energy range of 8–30 MeV/u from the HIRFL will be accumulated, cooled and accelerated to the high-energy range of 100–400 MeV/u in the main ring, and then extracted fast to produce RIB or highly charged heavy ions. The secondary beams (RIB or highly charged heavy ions) will be accepted and stored by the experimental ring for many internal-target experiments or high-precision spectroscopy with beam cooling. On the other hand, the beams with the energy range of 100–900 MeV/u will also be extracted from CSRm by using slow extraction or fast extraction for many external-target experiments.
119629879
Study of a prototype water Cherenkov detector for the Daya Bay neutrino experiment
The Daya Bay reactor neutrino experiment is designed to precisely measure the neutrino mixing angle theta(13). The anti-neutrino detectors are shielded by highly purified water against radioactivity and spallation neutrons from surrounding rocks. The water also serves as a Cherenkov detector to tag cosmic-ray muons, which induce main backgrounds. In order to study water purification and details of the detector response, a prototype water Cherenkov detector is constructed at the Institute of High Energy Physics (IHEP), Beijing. The detector is divided by Tyvek into two sections and viewed by two 8 in. photomultipliers. Cosmic-ray muons are used for detector response studies and a Monte Carlo simulation based on the Geant4 package shows good agreement with the experimental data. (C) 2012 Elsevier B.V. All rights reserved.
10034711
The beam energy calibration system for the BEPC-II collider
This document contains a proposal of the BEPC-II collider beam energy calibration system (IHEP, Beijing). The system is based on Compton backscattering of carbon dioxide laser radiation, producing a beam of high energy photons. Their energy spectrum is then accurately measured by HPGe detector. The high-energy spectrum edge will allow to determine the average electron or positron beam energy with relative accuracy about 3x10^-5.