On the spur lifetime and its temperature dependence in the low linear energy transfer radiolysis of water
Bibliographic record
Abstract
In the spirit of the radiation chemical "spur model", the lifetime of a spur (τ(s)) is an important indicator of overlapping spurs and the establishment of homogeneity in the distribution of reactive species created by the action of low linear energy transfer (LET) radiation (such as fast electrons or γ irradiation). In fact, τ(s) gives the time required for the changeover from nonhomogeneous spur kinetics to homogeneous kinetics in the bulk solution, thus defining the so-called primary (or "escape") radical and molecular yields of radiolysis, which are obviously basic to the quantitative understanding of any irradiated chemical system. In this work, τ(s) and its temperature dependence have been determined for the low-LET radiolysis of deaerated 0.4 M aqueous solutions of H(2)SO(4) and pure liquid water up to 350 °C using a simple model of energy deposition initially in spurs, followed by random diffusion of the species of the spur during track expansion until spur overlap is complete. Unlike our previous τ(s) calculations, based on irradiated Fricke dosimeter simulations, the current model is free from any effects due to the presence of oxygen or the use of scavengers. In acidic solutions, the spur lifetime values thus obtained are in very good agreement with our previous calculations (after making appropriate corrections, however, to account for the possibility of competition between oxygen and Fe(2+) ions for H˙ atoms in the Fricke dosimeter, an effect which was not included in our original simulations). In this way, we confirm the validity of our previous approach. As expected, in the case of pure, oxygen-free water, our calculated times required to reach complete spur overlap are essentially the same (within uncertainty limits) as those found in acidic solutions. This explicitly reflects the fact that the diffusion coefficients for the hydrated electron and the H˙ atom that are involved in the overall calculation of the lifetime of spurs in neutral or acidic media, respectively, are of similar magnitude over the 25-350 °C temperature range studied.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".