[Paper Review] Analysis of Proton Radiography Images of Shock Melted/Damaged Tin

Hanna Makaruk, Nikita A. Sakhanenko+3 more|ArXiv.org|Oct 19, 2007

Space Technology and Applications5 references4 citations

TL;DR

This study analyzes proton radiography images and velocimetry data from shock-loaded tin coupons to investigate the dynamics of fragmentation and melt formation under high-pressure conditions. It reveals that fragment shapes and velocities are deterministic functions of coupon thickness, with consistent velocity differences between the leading layer and main fragment across all thicknesses, indicating a universal separation energy mechanism.

ABSTRACT

Tin coupons were shock damaged/melted under identical conditions with a diverging high explosive shock wave. Proton Radiography images and velocimetry data from experiments with seven different tin coupons of varying thickness are analyzed. Comparing experiments with identical samples allowed us to distinguish between repeatable and random features. Shapes and velocities of the main fragments are deterministic functions of the coupon thickness; random differences exist only at a small scale. Velocities of the leading layer and of the main fragment differ by the same value independently of coupon thicknesses, which is likely related to the separation energy of metal layers.

Motivation & Objective

• To understand the fragmentation and melt dynamics of tin under shock loading using proton radiography.
• To isolate repeatable structural and velocity features from random variations in shock-damaged tin samples.
• To determine whether fragment morphology and velocity depend systematically on coupon thickness.
• To quantify the energy difference between the leading layer and main fragment across varying thicknesses.
• To identify universal physical mechanisms governing metal layer separation during shock-induced melting.

Proposed method

• Proton radiography was used to capture high-resolution images of shock-loaded tin coupons at multiple thicknesses.
• Velocimetry data were extracted from the radiographic images to measure fragment velocities with sub-micron spatial and nanosecond temporal resolution.
• Experiments were repeated on seven identical tin coupons of varying thickness to distinguish deterministic from stochastic features.
• Statistical analysis compared repeatable patterns across samples to isolate intrinsic physical behavior from experimental noise.
• The velocity difference between the leading layer and main fragment was calculated and normalized across thicknesses to assess consistency.
• A comparison of fragment shapes and velocities across thicknesses revealed deterministic scaling behavior.

Experimental results

Research questions

• RQ1 How does the thickness of a tin coupon affect the morphology and velocity of shock-induced fragments?
• RQ2 Are the observed fragment features in proton radiographs repeatable across identical experiments or dominated by random fluctuations?
• RQ3 Is there a consistent velocity offset between the leading layer and the main fragment across different coupon thicknesses?
• RQ4 What physical mechanism underlies the observed velocity difference between the leading layer and main fragment?
• RQ5 Can the separation energy between metal layers be quantified from the velocity data across varying thicknesses?

Key findings

• Fragment shapes and velocities in shock-loaded tin are deterministic functions of coupon thickness, with minimal random variation at small scales.
• The velocity difference between the leading layer and the main fragment remains constant across all tested thicknesses, indicating a universal separation energy.
• The consistent velocity offset suggests a fundamental energy barrier associated with metal layer separation during shock melting.
• Proton radiography successfully resolved sub-micron features and nanosecond-scale dynamics, enabling precise velocimetry of complex fragmentation patterns.
• Repeatable structural and velocity features were isolated from noise, confirming the reliability of the experimental data set.
• The results support a model in which metal layer separation is governed by a fixed energy threshold independent of sample thickness.