Speaker
Description
Particle Deposition Measurements in the Cleanroom of the ETPathfinder
Research into the influence of the Beamsplitter assembly process on particle deposition
Author:
Levon Mnoyan
Affiliations:
1. Zuyd University of Applied Sciences, Heerlen
2. SAC-Nederland, Kerkrade
3. ETPathfinder, Maastricht (Maastricht University)
Topic: Particle deposition measurements during construction of the beamsplitter
Keywords: Particle deposition, cleanliness, beamsplitter, contamination risk.
Referred presentation type: No preference
Particle deposition is a fundamental factor for the performance of optical components within the Einstein Telescope, as contamination can reduce optical accuracy and disrupt the ultra-high vacuum (UHV). This work focuses on the question: What is the effect of the mechanical, electrical, and optical assembly phases of a beamsplitter on particle deposition in the cleanroom of the ETPathfinder in Maastricht, in accordance with the ISO 14644 standard? The standard emphasizes the classification of air purity; specifically, ISO 14644-17: Particle deposition rate applications is examined.
The research itself was conducted in collaboration with SAC-Netherlands and the ETPathfinder facility, an R&D environment in preparation for the Einstein Telescope, and focuses on the beamsplitter assembly process. Measurements were performed in the cleanroom within the Faculty of Science and Engineering (FSE, Maastricht) using a Particle Deposition Monitor (PDM), in which particle counts, size distributions, and the Particle Deposition Rate (PDR) were analyzed for various assembly phases. Furthermore, it measures particle counts per unit area (PAC). The PDM is an optical instrument that analyzes particles; it was developed, manufactured, and supplied by SAC-Nederland.
The results show that the mechanical and electrical assembly phases, in particular, contribute the most to particle deposition, with a maximum PDR of 51,500 particles/m²/hour and dominant particle sizes between 15 µm and 40 µm. Important sources of contamination are human activity, material movement, and inconsistent adherence to cleanroom protocols.
Although all measurements comply with the ISO Class 8 standard, they prove insufficient for UHV applications such as beam splitters. The results emphasize the need for stricter contamination control to ensure the performance and reliability of optical components within the Einstein Telescope and Einstein Telescope Pathfinder.