Errors in the field reconstruction using CR-39 proton radiographs with high fluence variation.

Autor:	Foo BC; MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA., Buschmann BI; MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA., Cufari M; MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA., Dannhoff SG; MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA., DeVault A; MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA., Evans TE; MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA., Johnson TM; MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA., Kunimune JH; MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA., Lawrence Y; MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA., Pearcy JA; MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA., Reichelt BL; MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA., Russell L; MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA., Vanderloo N; MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA., Vargas J; MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA., Wink CW; MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA., Johnson MG; MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA., Séguin FH; MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA., Petrasso RD; MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA., Frenje JA; MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA.
Jazyk:	angličtina
Zdroj:	The Review of scientific instruments [Rev Sci Instrum] 2024 Oct 01; Vol. 95 (10).
DOI:	10.1063/5.0219510
Abstrakt:	CR-39 proton radiography is an experimental charged-particle backlighter platform fielded and used at OMEGA and the NIF to image electric and magnetic fields in a subject plasma. Processing a piece of CR-39 involves etching it in hot NaOH, and the etch time can greatly impact the background-to-signal ratio (BSR) in low-fluence (≲4 × 104 cm-2) regions and detection efficiency in high-fluence regions (≳7 × 105 cm-2). For CR-39 data with high fluence variation, these effects mean that any single etch time will result in ≳15% error in the measured signal in either the high- or low-fluence regions. This study aims to quantify the impact of the etch time on the BSR and efficiency losses and how these affect the field reconstruction. Experiments at the MIT Linear Electrostatic Ion Accelerator provided empirical values of the BSR and efficiency losses as a function of the fluence and etch time for fluences ranging from 3 × 103 to 7 × 105 cm-2. Synthetic radiographs were generated with known fields and modulated based on empirical values of BSR and efficiency losses. The fields were reconstructed using a Monge-Ampère code with the modulated radiographs as input. The results indicate that combining short and long etches allows for more accurate analysis of radiographs with high fluence variation, with the mean squared error of the reconstructed fields decreasing by factors of 1.2-7 compared to the reconstructions using only one etch time. (© 2024 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).)
Databáze:	MEDLINE
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