To the positive miscut influence on the crystal collimation efficiency

TL;DR

This paper investigates how positive miscut angles in crystal collimators can significantly reduce efficiency and increase nuclear reaction rates, impacting the Large Hadron Collider's collimation system performance.

Contribution

It is the first to demonstrate the detrimental effect of positive miscut on crystal collimation efficiency and provides estimates for its impact on future LHC operations.

Findings

Positive miscut can increase nuclear reaction rate by 4.5 times.

Positive miscut deteriorates channeling collimation efficiency.

Discusses implications for future LHC crystal collimation systems.

Abstract

The paper concerns the crystal based collimation suggested to upgrade the Large Hadron Collider collimation system. The issue of collimation efficiency dependence on the muscut angle characterizing nonparallelity of the channeling planes and crystal surface is mainly addressed. It is shown for the first time that even the preferable positive miscut could severely deteriorate the channeling collimation efficiency in the crystal collimation UA9 experiment. We demonstrate that the positive miscut influence can increase the nuclear reaction rate in the perfectly aligned crystal collimator by a factor of 4.5. We also discuss the possible miscut influence on the future LHC crystal collimation system performance as well as suggest simple estimates for the beam diffusion step, average impact parameter of particle collisions with the collimator and angular divergence of the colliding particle beam portion.