Application of E×B Field to a Side-Extracting PIG Ion Source

Results are given of a preliminary experiment on the application of an E×B field to the side-extraction PIG ion source. With an E×B field a significant increase in the extracted ion current was obtained even at a constant PIG discharge current

Back-scattering Energy Spectra near the Critical Angle for Proton Channeling

Back-scattering energy spectra of 1.0 and 1.5 MeV protons from Si single crystals have been studied. At the shoulder of the dipshoulder pattern of the scattering yield around {110} channeling direction, the energy spectrum shows a conspicuous hump in the high energy part. The simple model is proposed for the origin of this hump

Neutral Fractions in Proton Beams Passing through Solids

Neutral fractions of proton beams backscattered from thick C and Au targets and transmitted through thin C, Si, and Au foils were measured in the energy range 100-310 keV. Proton was more neutralized in the case of the Au target than the C and Si targets. An emergence angle dependence was not found within the experimental uncertainty. Effects of the surface contamination were discussed and the thickness of the surface contamination was estimated to be about 10 A

Transmission of Fast Protons through Si Single Crystals

Transmission of 3.0 MeV protons through Si single crystal foil has been studied. From the energy spectra of transmitted protons, stopping powers of Si along ＜111＞ axis and {110} plane have been found to be 0.54 and 0.65 times that of random direction, respectively. Photographs of the transmission patterns observed on a ZnS screen are shown, and some interesting features are pointed out

Some Characteristics of the End-Extraction PIG Heavy Ion Source with Cold Cathode

Intensity, emittance, and brightness of the extracted argon beam from the end-extraction PIG ion source were measured as a function of gap-length between the cathode and the extraction electrode. From these data the optimum gap-length was determined. Cathode sputterings of Ta, Al, Cu, and C cathodes were compared. For argon gas the graphite cathode was found to have the longest life-time

Excitation of the n=4 Levels of He⁺ by the Impact of H⁺, He⁺ and He²⁺ Ions

The emission cross sections of Hell (4→3) 4686 Å line by the incident beams of 0.5-1.5 MeV H⁺, 1.0-2.5 MeV He⁺ and 1.0-2.0 MeV He²⁺ are studied. By measuring the lateral distribution of the light intensity, the excitation of He⁺ (n＝4) levels is found to be caused by direct collision. The emission cross section by the proton impact is due to the ″ionization process″ and shows an E⁻¹ dependence, while that by the helium ion impact is due to the “charge transfer process” as well as the “ionization process” and shows a steeper energy dependence

Excitation Process of Helium Atoms by the Impact of 100-200 keV Protons

Excitation cross sections of some states of helium by the impact of 100-200 keV protons were studied under various excitation conditions. The lateral distributions of light source were also measured. In the higher target gas pressure region, the excitation of n¹P(n＝3, 4) levels are greatly increased by the effect of the imprisonment of resonance radiations, and the 4¹, ³D and 3³P levels are also influenced by the effect of a collisional transfer. The 4¹S state is mainly excited by a direct collision with incident protons even at the higher gas pressure

Back-scattering of Fast Protons from Silicon Single Crystals

The axial and (110) planar channeling of 200 keV protons in silicon have been studied by measuring the yield of back-scattering (scattering angle : 135°). The results are in good agreement with the theory of Lindhard and Erginsoy. The observed critical angles and the minimum scattering yield agree with the theoretical values with decreasing depth below the crystal surface. The analysis of the energy spectra of backscattered protons indicates that the axial and planar channeling probabilities of the protons at the clean surface are 0.93 and 0.66, respectively, and that the shoulder parts of the yield curves are mainly due to back-scattering from the surface layer of the crystal rather than to some imperfections of its surface

Excitation of Nitrogen Molecule by the Impact of 80-160 kev Proton

Light emission from nitrogen molecules excited by the impact of 80-160 kev protons was studied over a wave length ranging from 3300 to 5400 Å. The lateral distributions of the light intensities were also measured. From the target gas pressure dependence of the light intensities and their lateral distributions, it was shown that the state B²Σ⁺ᴜ of N⁺₂ was excited by a direct proton collision, and that the state C³IIᵤ of N₂, having a singlet-triplet mixing, was excited by secondary processes

Heavy-Ion Rutherford Backscattering Spectrometry : A Comparison of ¹¹B with ⁴He Ions

The Rutherford backscattering spectrometry was examined with ¹¹B and ⁴He ions. Backscattering spectra improve in the mass resolution, the depth resolution and the channeling minimum yield when 6 MeV ¹¹B ions are used instead of 2 MeV ⁴He ions, which have been used commonly. Then the terminal voltage of a 1.7 MV tandem Cockcroft-Walton accelerator was calibrated by means of a combination of the ²⁷Al(p, γ)²⁸Si resonance method and a new iterative method using ¹H and ⁴He ions. The true terminal voltage of the accelerator is lower than the corresponding nominal values, and the deviation quadratically increases with increasing voltage