1 / 9

Advanced Gas Leak Measurement Techniques for Ionization Modules at Duke University

This document outlines the gas leak testing protocols for ionization modules, specifically detailing the required operating conditions involving xenon and carbon dioxide gases. The methodology includes procedures for measuring leak rates, monitoring pressure changes, and calculating leak measurements with considerations of temperature and pressure variations. Key highlights include a leakage threshold of <0.1 mBar/Bar/minute and strategies for minimizing measurement errors. The text emphasizes the importance of precise leak measurement for maintaining module integrity and improving testing processes.

ezra
Télécharger la présentation

Advanced Gas Leak Measurement Techniques for Ionization Modules at Duke University

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Module Gas Leak Chiho Wang Duke University

  2. Gas leak requirements • Operating condition: • ionization gas at 1 atm with 70% Xe • purging gas at 1 atm with 100% CO2 • allow 10 volume / year of Xe loss • Measurement simulates Xe loss with: • Same gas (or different gases assuming both are ideal gas) in each gas volume • Slight over pressure of ionization gas volume • monitoring pressure change over time (indifference of composition change) • Present requirement at Duke/IU: < 0.1 mBar/Bar/minute

  3. Module leak test setup

  4. Module leak test setup Reference Volume

  5. Leak Measurement • Measurement procedure: • pressurize/equalize module and reference tank pressure to ~ 20mB above room atm • isolate module from reference tank • monitor pressure change between reference tank and module over time • Leak rate is calculated = dP/P/T • dP = pressure difference Tank - Module (mBar) • P = module pressure vs room (Bar) • T = elapsed time (minute)

  6. Module 2.07 mechanical ~42 hrs, Leak rate = -0.007 mB/B/min

  7. Measurement Accuracy • Affecting factors: • Temperature may swing 2ºC during measurement. • The measurement assumes module and reference tank responds to temperature change equally. • Suppose there’s a 10% mismatch in their responses, the error in dP measurement would be ~ 10% * 2/300*1013 ~ 0.68 mB • To wash out temperature effect with time to 0.05mB/B/min would be: 0.05 = 0.68(mB) / 0.02(Bar) / T (minute) T ~ 675 minutes = 11.3 hours • Room pressure may swing 10s of mBar and affect module P used in calculating leak rate • This, however, can be corrected by taking average P or integrating P over time.

  8. Module leak measurements * measured at mechanical completion

  9. Summary • Modules built are leak tight • Continue to improve leak measurement and understand the measurement error • Added barometer to obtain absolute module pressure • Try to understand temperature dependence of dP between module and tank • Try different method of leak rate calculation, e.g. using P/T = nR/V without using reference tank.

More Related