Fluence function

Webb R and Carter G (1979) Diffieulties in dedueing disordering meehanisms from experimental studies of disorder - ion fluence functions in ion irradiation of semiconductors. Radiation Effects 42 159-168 Weber WJ (1983) Radiation-indueed swelling and amorphization in Ca2Nds(Si04)602. Radiation Effects 77 295-308... 

The trend curve was pieced together by P.N. Randall of the NRC using evaluations and analyses performed by others. The Revision 2 trend equation uses CF values that are tabulated chemistry factors (in UK units) for welds and base metals based on Cu and Ni content (wt%), and FF is a more complex fluence function (f is again expressed as lO n/cm, E>lMeV) ... 

In response to the development of the revised EWO embrittlement correlation method, detailed independent review was performed using both mechanistic and statistical bases. The results suggested that a more simplified version of the revised EWO correlation is also appropriate. Five parameters were removed from the mean correlation for simplification the three A parameters were reduced to a single value, the effect of P was removed from the SMD, the effect of flux-time (ft) was eliminated from the CRP fluence function and the long-time bias term was eliminated. This simplified version of the trend equation was approved in ASTM E 900-02. T e simplified version in ASTM E 900-02 follows the form of Eq. 11.4 using the terms SMD and CRP ... 

In order to revise the embrittlement correlation equation, Todeschini et al first tried to fit a simple power law neutron fluence function to the database to see the effect of some possible key parameters on the residuals. It was identified that Cu and P have a strong effect on both base and weld metals, Ni has an effect only in the presence of Cu, Mn has some effect on weld but the increase of Mn makes the degree of embrittlement smaller, and Si has a very weak effect. Among these effects, the evidence for Mn and Si effects was not sufficient to be included in the model, and thus it was decided that only Cu, P and a cross-term of Cu and Ni should be included in the new correlation. This test did not support the effects of product form and flux within the new French database. 

Wark, Whitlock, and co-workers [72]-[75] extend these ideas in shock compression of < 111 >-oriented silicon single crystals. The method of producing the shock wave differs from previous X-ray diffraction studies, but the basic concepts are the same. Higher X-ray fluences result in a time resolution of 0.05-0.1 ns. This permits a sequence of exposures at various irradiances and delay times, thus mapping the interatomic spacing of the shock-compressed surface as a function of time. 

The "add-to-memory" signal averaging method currently available to us distorts fluorescence intensity versus time plots when the fluorescence intensity is a non-linear function of incident laser energy and the laser energy varies from shot to shot. For this reason we have not attempted detailed kinetic modelling of the observed fluorescence intensity decay curves recorded at high 532 nm laser fluence. 

Fig. 10. (a) G11,j (b) C2H3 signal intensities as a function of photolysis laser fluence. 

Ne+ ion irradiation of a 0.13 nm thick film produces a metallic silvery film. A plot of the infrared COO vibrations as a function of fluence in Figure 10 shows that the intensity decreases with approximately the same functional dependence as in the He ion irradiation, but at a dose that is 17 times lower. In addition, a new band appears at 1616 cm-1, peaking at a dose of — 1.7x1012 ions/cm2, then decreasing rapidly to the same level as the original acetate bands. This may represent the formation of some monodentate acetate species as the palladium acetate trimers are cleaved. In situ infrared spectra of the He ion-irradiated films show a similar band of much smaller relative intensity. 

OL behavior is assessed simply by monitoring the transmission of a (usually solution) sample as a function of the incoming laser fluence measured in joules per square centimeter (rather than intensity in watts per square centimeter).22,23 Limiting thresholds Fth, defined as the incident fluence at which the actual transmittance falls to 50% of the corresponding linear transmittance, are then commonly quoted. Since excited-state absorption processes generally determine the OL properties of molecules, the excited-state structure and dynamics are often studied in detail. The laser pulse width is an important consideration in the study of OL effects. Compounds (1-5)58-62 are representative non-metal-containing compounds with especially large NLO and/or OL... 

Fig. 3.9. Left photoelectron intensity from TbTe3 surface as a function of energy and momentum for different time delays, showing the ultrafast closing of the CFW gap marked with a dot. Right Time-dependent binding energy of the Te band (lower trace) and the CB (upper trace), exhibiting a periodic modulation at 2.3 and 3.6 THz, respectively, under strong excitation fluence (2mJ/ cm2). From [22]...

Fig. 3.16. Left transient reflectivity changes of TTF-CA with double pulse excitation at At = 0.62 ps (=T) for various pump fluences, indicating the super-linear enhancement of the coherent phonons with increasing excitation density. The pump pulses are indicated by grey lines. Id indicates the excitation density of each pulse in the pulse pair in unit of Io = 1 x 1016 photons/cm2. Right Maximum AR/It, (open circles) and the oscillation amplitude (closed circles) as a function of Id/Io-From [44]...

Sensitivity data for 193 nm exposures were obtained by imaging 1 mm to 1 cm diameter spots in a 1.2 pm thick poly(styrene) film using a Questek ArF excimer laser. Sensitivity was found to be a function of the fluence. For example, one pulse was sufficient to result in a full thickness image after treatment with TiCU and O2 RIE when the fluence was 6 mJ/cm2/pulse (Figure 10). Considerably more dose (32 mJ/cm2) was required to obtain the same result when the fluence was 1... 

The fluorescence spectra measured just upon ablation are given in Figure 2A as a function of laser fluence. The contribution below 370 nm was suppressed, as a Hoya L37 filter was used in order to cut off the laser pulse. Fluorescence spectra of this polymer film consist of sandwich (max. 420 nm, lifetime 35 ns) and partial overlap (max. 370 nm, lifetime 16 ns) excimers (20). The latter excimer is produced from the initially excited monomer state, while the sandwich excimer from the partial overlap excimer and the monomer excited states. Since these processes compete with efficient interactions between identical and different excimers (Si - Si annihilation) (12), the sandwich excimer is quenched to a greater extent compared to the partial overlap one under a high excitation. Actually the fluence-dependent spectral change around the threshold can be interpreted in terms of Si - Si annihilation. 

Temporal characteristics at early stages were elucidated by measuring fluorescence intensity with the gate time of 1.74 ns as a function of the delay time. Compared to the laser pulse, the time where the maximum intensity is attained shifts to the early stage as the laser fluence becomes high. Of course, we could not find out any decay component with intrinsic fluorescence lifetime of 17 and 35 ns. It is concluded that an Si - Si annihilation occurs quite efficiently during the pulse width. 

The ambient temperature Tamb is ignored since T T amb. The assumption of a zeroth-order dissociation process implies that Thermal a Thus, A a A and E aE. 64 It should be noted that L thermal reaches a limiting value of A1 with increasing fluence. Fphoto increases with fluence, but as a very slow logarithmic function. 

---