The 53.667 MHz continuous-wave heavy ion RFQ has been designed and manufactured for the SSC-LINAC project.This four-rod RFQ accelerates ions with maximum mass to charge ratio of 7 from 3.728 keV/u to 143 keV/u.Measure...The 53.667 MHz continuous-wave heavy ion RFQ has been designed and manufactured for the SSC-LINAC project.This four-rod RFQ accelerates ions with maximum mass to charge ratio of 7 from 3.728 keV/u to 143 keV/u.Measurements have been carried out to check the RF performance of the cavity and the quality of the electric field.The S11 of the power coupler is adjusted to better than-44 dB,and the Q0 of the cavity is 6440.The quality of the electric field is evaluated by the perturbation method.The measurement procedure and data analysis will be discussed in detail.The error due to gravity of the perturbation bead has been corrected by averaging the fields in different quadrants.As a result,the unflatness of the electric field is±2.5%,and the dipole field component distributes from 0%to 20%in different longitudinal positions,which indicates the asymmetry of the quadrupole field.The unflatness of the quadrupole field distribution represents a good agreement with the simulation results.High power RF test and beam commissioning of the RFQ are on schedule in early 2014.展开更多
Niobium-doped indium tin oxide （ITO：Nb） thin films are fabricated on glass substrates by radio frequency （RF） magnetron sputtering at different temperatures. Structural, electrical and optical properties of the f...Niobium-doped indium tin oxide （ITO：Nb） thin films are fabricated on glass substrates by radio frequency （RF） magnetron sputtering at different temperatures. Structural, electrical and optical properties of the films are investigated using X-ray diffraction （XRD）, atomic force microscopy （AFM）, ultraviolet-visible （UV-VIS） spectroscopy and electrical measurements. XRD patterns show that the preferential orientation ofpolycrystalline structure changes from （400） to （222） crystal plane, and the crystallite size increases with the increase of substrate temperature. AFM analyses reveal that the film is very smooth at low temperature. The root mean square （RMS） roughness and the average roughness are 2.16 nm and 1.64 nm, respectively. The obtained lowest resistivity of the films is 1.2 × 10^4 Ω-cm, and the resistivity decreases with the increase of substrate temperature. The highest Hall mobility and carrier concentration are 16.5 cmVV.s and 1.88× 10^21 cm^-3, respectively. Band gap energy of the films depends on substrate temperature, which is varied from 3.49 eV to 3.63 eV.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.11079001 and 10905003)the Linear Accelerator Center of PKU-IMPCAS
文摘The 53.667 MHz continuous-wave heavy ion RFQ has been designed and manufactured for the SSC-LINAC project.This four-rod RFQ accelerates ions with maximum mass to charge ratio of 7 from 3.728 keV/u to 143 keV/u.Measurements have been carried out to check the RF performance of the cavity and the quality of the electric field.The S11 of the power coupler is adjusted to better than-44 dB,and the Q0 of the cavity is 6440.The quality of the electric field is evaluated by the perturbation method.The measurement procedure and data analysis will be discussed in detail.The error due to gravity of the perturbation bead has been corrected by averaging the fields in different quadrants.As a result,the unflatness of the electric field is±2.5%,and the dipole field component distributes from 0%to 20%in different longitudinal positions,which indicates the asymmetry of the quadrupole field.The unflatness of the quadrupole field distribution represents a good agreement with the simulation results.High power RF test and beam commissioning of the RFQ are on schedule in early 2014.
文摘Niobium-doped indium tin oxide （ITO：Nb） thin films are fabricated on glass substrates by radio frequency （RF） magnetron sputtering at different temperatures. Structural, electrical and optical properties of the films are investigated using X-ray diffraction （XRD）, atomic force microscopy （AFM）, ultraviolet-visible （UV-VIS） spectroscopy and electrical measurements. XRD patterns show that the preferential orientation ofpolycrystalline structure changes from （400） to （222） crystal plane, and the crystallite size increases with the increase of substrate temperature. AFM analyses reveal that the film is very smooth at low temperature. The root mean square （RMS） roughness and the average roughness are 2.16 nm and 1.64 nm, respectively. The obtained lowest resistivity of the films is 1.2 × 10^4 Ω-cm, and the resistivity decreases with the increase of substrate temperature. The highest Hall mobility and carrier concentration are 16.5 cmVV.s and 1.88× 10^21 cm^-3, respectively. Band gap energy of the films depends on substrate temperature, which is varied from 3.49 eV to 3.63 eV.
