摘要:

In the considered method of the H−beam diagnostics the information on beam parameters is taken out via the fast H° atoms which are produced in definite quantum states at the charge‐exchanging area of the transport line. The beam parameters are determined in the convenient area outside the transport line by means of a compact magnetic analyzer and electrons produced from a selective photoionization of the useful quantum state of the H° atoms. The realization of such diagnostics at the area of the charge‐exchanging H−→P injection of the meson factory storage rings is considered. If the information on the H−beam parameters is taken out via the fast H° atoms in metastable 2s‐quantum state the accuracies of correspondence between electron and ion distributions ≊10−2% in energy and ≊3×10−5rad in angle coordinate can be obtained.

ISSN:0094-243X    

DOI:10.1063/1.44767

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

A correlation method of nonperturbative control on energy spectra of negative (H−,D−) ions, profile, and transverse beam emittance at a bending transport line area, is suggested. The method is based on measurements of the cross correlation function between a photon flux from laser radiation, pseudorandomly modulated in time, and that of the fast (H°,D°) neutrals produced at a photon target and recorded on a drift distance. Characteristics of the apparatus for realization of the proposed diagnostical method at a source of H−(D−) ions by means of the time‐integrated correlators based on the charge‐coupled devices is considered.

ISSN:0094-243X    

DOI:10.1063/1.44768

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

The previously proposed method of nonperturbative diagnostics for negative ion beams based on electrons produced from near‐threshold photodetachment of ions, is considered. A compact multifunctional apparatus for realization of this method at a meson factory linacs (MFL) and measuring various beam parameters of high‐energy H−ions, is proposed. For the H−beam at the Moscow MFL can be obtained the accuracies of correspondence between electron and ion distributions ≊3×10−2% in energy and ≊5×10−5rad in angular coordinate.

ISSN:0094-243X    

DOI:10.1063/1.44769

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

The Fulcher band emission spectrum is used to determine rotational temperatures in the FOMSCE plasma setup. The measured temperatures are found to vary from 500 to 700 K, whereas usually in this kind of plasmas they are very close to room temperature. In this paper the interpretation of the spectra will be discussed. The influence of some plasma settings on the measured temperature will be presented.

ISSN:0094-243X    

DOI:10.1063/1.44770

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

A photodetachment technique has been used to measure the negative ion densities in both the driver and extraction regions of a tandem, multicusp ion source operating with H2and D2. The measurements have been made at electron densities of up to 2×1018m−3by using time resolved measurement techniques while operating the source in a pulsed mode. This also allows a study of the afterglow (post discharge). Of particular interest has been the comparison between operation in hydrogen and deuterium. Under the same operating conditions, the negative ion density in deuterium is consistently found to be about 75% of that in hydrogen. An increase in H−and D−densities in the early post discharge has been observed in both the extraction and driver regions.

ISSN:0094-243X    

DOI:10.1063/1.44835

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

We have examined angular distributions of hydrogen atoms with energies of 20−200 KeV resulting from photoneutralization of H−beam ions by linearly polarized laser radiation. (AIP)

ISSN:0094-243X    

DOI:10.1063/1.44771

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

Measurements of negative ion density after initial laser photodetachment show good agreement with a ballistic theory of negative ion return early in time, but show a much slower return than predicted by theory late in time. Here we develop an explanation based on the establishment of a hole in the negative ion velocity space, which would then be filled in by collisions on a slower time scale.

ISSN:0094-243X    

DOI:10.1063/1.44772

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

The possibility of measuring divergence of high intensity atomic and ionic beams by using the method of Doppler laser spectroscopy, proposed by the author, is considered. This method, which is based on the detection of induced atomic radiation, allows for increased efficiency of detecting primary levels in comparison with passive Doppler spectroscopy which uses detection of spontaneous radiation.

ISSN:0094-243X    

DOI:10.1063/1.44773

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

The experimentally measured dependence upon the acceleration voltage of the negative ion current intercepted on a Faraday Cup is compared to theoretical computations. It is shown that the secondary positive ions generated within the electron suppression electrode and accelerated into the plasma source, have a significant effect on the plasma extraction sheath and presheath potentials and explain the experimental data.

ISSN:0094-243X    

DOI:10.1063/1.44808

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

Two dimensional electrostatic particle simulation was done to simulate the extraction of negative ions from the plasma including electrons, ions, and negative ions. The simulation system consists of walls, plasma region, vacuum region, various electrostatic grids such as plasma grid, extraction grid, and acceleration grid. There is a external magnetic field in the extraction grid region. Full dynamics of charge particles are followed. It is shown that the modeling of source region is crucial to approach the stationary state. Only negative ions are successfully accelerated to the acceleration grid if the various parameters are properly chosen. Selfconsistent effects such as sheath formation, space charge effect, the shape of plasma‐vacuum boundary are found to be important for the extraction of negative ions.

ISSN:0094-243X    

DOI:10.1063/1.44809

出版商:AIP    

年代:1992

数据来源: AIP