CERN antiproton target: hydrocode analysis of its core material dynamic response under proton beam impact

TL;DR

This study uses hydrocodes to analyze the dynamic response of CERN's iridium antiproton target core under proton beam impact, identifying key phenomena and potential design improvements for durability.

Contribution

It provides a detailed numerical analysis of the target material's dynamic behavior, highlighting phenomena and proposing a cladding solution to reduce tensile stresses.

Findings

High frequency radial waves cause destructive pressure responses

End-of-pulse tensile waves significantly affect the response

Tantalum cladding reduces tensile pressure by 40%

Abstract

Antiprotons are produced at CERN by colliding a 26 GeV/c proton beam with a fixed target made of a 3 mm diameter, 55 mm length iridium core. The inherent characteristics of antiproton production involve extremely high energy depositions inside the target when impacted by each primary proton beam, making it one of the most dynamically demanding among high energy solid targets in the world, with a rise temperature above 2000 {\deg}C after each pulse impact and successive dynamic pressure waves of the order of GPa's. An optimized redesign of the current target is foreseen for the next 20 years of operation. As a first step in the design procedure, this numerical study delves into the fundamental phenomena present in the target material core under proton pulse impact and subsequent pressure wave propagation by the use of hydrocodes. Three major phenomena have been identified, (i) the dominance of a high frequency radial wave which produces destructive compressive-to-tensile pressure response (ii) The existence of end-of-pulse tensile waves and its relevance on the overall response (iii) A reduction of 40% in tensile pressure could be obtained by the use of a high density tantalum cladding.