Beam target

Simulation spectra were generated using parameters that describe the ion beam, target and detector geometry, beam and detector resolution, and sample characteristics. The sample parameters, which include the number of layers and the areal density and atomic composition of each layer were then varied until the simulation conformed to the experimental data. The HIBS spectra were analysed using a modified version of the RBS analysis program. 

Fig. 12. Experimental setup for observation A. (a) - channel scheme p - internal proton beam, Target - target mechanism, Col - collimator, MS - magnetic shield (b) - magnet and detectors M - poles of spectrometer magnet, VC — vacuum chamber, DC - drift chambers, H - scintillation hodoscopes, S,SM - scintillation counters, C -gas Cherenkov counters, Absorber - cast-iron absorber, MC - monitor counters...

Here, d is the distance from the beam target in the X-ray tube to the desired point on the other side ofthe protective barrier. Usually the product. It, is replaced by the single factor W. All the... 

Most of the results have been interpreted up to now in terms of two models representing opposite limiting cases the beam target and the boiler. In the beam target model, it is postulated that there is a clear dis-... 

We note that the possibility of providing an ensemble of fully spin polarized He nuclei opens up very interesting possibilities in nuclear physics, providing polarized beam targets, spin analysis in nuclear reactions, etc. [7.65],... 

Literature on the ammonium radical up to February 1936 is covered in an early Gmelin volume Ammonium 1936, pp. 6/7. Some later work dealing with the possible existence of a neutral NH4 radical has been reviewed [1]. NH4 has been proposed as being formed as an intermediate in the reaction of NH4 with the hydrated [2] or ammoniated [3] electron. The formation of a metallic phase of NH4 was occasionally discussed for a more recent paper, see [4]. An ion-beam target-gas study in 1980 gave the first conclusive evidence for the existence of the ammonium radical. In 1981, the radical was identified as the carrier... 

The ionization potential Ej(NH4) = 4.73 0.06 eV was obtained in an ion-beam target-gas experiment [8]. Ab initio values Ej(NH4) = 4.56 to 4.75 eV, Ej(ND4) = 4.53 to 4.57 eV, and Ej(NT4) = 4.50 to 4.55 eV were obtained at the single-double Cl level. The range of values results from the different values of the zero-point energies that were used [18]. A neutralization-reionization study showed that the efficiency of the collisional ionization of a fast beam of ND4 by various target gases decreases in the order N02>02>N2>He... 

The lifetime of the 3p p2 state of ND4, t = 4.2 ns, was determined in an ion-beam target-gas study. Predicted values of the radiative lifetime, 22 to 28 ns, obtained [10] using ab initio results [25, 31, 32], are much longer, indicating that ND4 decays primarily by predissociation [10]. 

J. A. Lettry, Exotic Ion-Beams, Targets and Sources, CERN, Geneva, Switzerland, http //arxiv.Org/PS cache/physics/pdf/0009/0009036.pdf... 

Estimate the Auger wavelength of x-rays emitted when Cu (Z= 29) is used as an electron beam target and an n = 2 electron falls to a Is Bohr orbital x-ray = L445 A). 

Let us return now to elementary molecular reactions. For example, consider a beam-target gas arrangement with a chemiluminescent exchange reaction where... 

T-HjCHD, Dj). An ion-beam target-gas study showed that the N4 +D2 >N2D + N2 + D channel dominates other available reaction channels in addition to N2D, only a comparatively small amount (<5%) of N2 from collision-induced dissociation was detected [5]. Drift tube studies showed significantly more (13%) [2] or only N4H (100%) [6] to be formed in N4+H2 reactive collisions. The difference in product distributions is attributed [5] to the single [5] and multiple collision [2, 6] conditions that were present. Thermal rate constants at 300 K for the N2H and N2D product channels in the reactions of N4 with H2... 

The energy dependence of the cross sections for the reactions of thermal N4 ions with H2, HD, and D2 was determined for center-of-mass collision energies from thermal up to 5 eV using the ion-beam target-gas technique. The total cross section for the reactions with HD (N4 + HD->N2H (N2D ) +D(H)) is equal to the cross sections for the reactions with H2 and D2. An isotope effect was observed in the reaction with HD at energies above 0.1 eV, formation of N2D" over N2H is favored [5]. 

Typical for reactions with a barrier, the cross sections for the N2H and N2D product ions rise with increasing collision energy up to 3 eV. Above 3 eV the cross sections decrease, possibly due to dissociation of the product ion. For the reactions with H2, D2, and HD, an activation energy of 0.09 0.03 eV at 0 K was obtained from the reaction thresholds which were determined in ion-beam target-gas experiments [5]. From Arrhenius plots of temperature-dependent [7] and collision-energy-dependent [9] drift tube data, the following activation energies were obtained H2, 0.15 0.01 [7], 0.16 0.01 D2, 0.17 0.01 eV [9]. 

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