[Aiden, Cao]

1. Helium leak test

• 2:00 pm: Uninstall regulator from nitrogen gas tank and move to helium gas tank. Place helium onto cart and move to the rear door of the clean tent. With the tank remaining outside, feed hose through the flexible wall to use in clean tent - See attached image
• 2:25 pm: Start Helium leak test: At each CF connection, He gas is sprayed while its level is monitored with the RGA in leak detection mode. A constant flow of helium is maintained until the level of helium detected by the RGA plateaus out.
  • All connections show low helium leak detected (< 3e-11 Amp)
  • The connections with highest leak detected are from reducing cross to flex hose and cross to RGA. They are on 2 - 3e-11 Amps. All other connections are less than 8e-12 Amps. We verified tightness of these two connection but they cannot be tighten any further

2. Argon calibrated leak test

• We opened the Ar calibrated leak. Upon opening the valve to allow Ar to flow through, we can see a surge in pressure measured by the gauges from 6.7e-7 mbar to 1.2e-6 mbar. This is then drop down and stabilised around 8.9e-7 after 5 minutes.
• Upon the the equilibrium is reached, we ran RGA scan twice in Analog mode with the following settings:
  • Points Per AMU: 10
  • Start Mass : 1
  • End Mass : 100
  • Focus Voltage: 90 V
  • Channel Electron Multiplier (CEM) : On
  • CEM Voltage: 1060 V
  • Unit: Amps (ion current)
  The settings is saved as rga100amu_scan.rga RGA application file in C:/Users/controls/Documents/Vacuum/VacuumChamber/RGA. The data file is saved in Data folder as ArLeak_230512.txt. This file contains the current values for corresponding AMUs. Using this dataset, we can obtain our chamber outgassing rate.
• Using RGA_scan_process.py , which is adapted from Mike Zucker's Matlab code E2000071, and the Ar calibrated leak posted in elog 95 we can compute the outgassing rate to be 150.5E-10 Torr l/s . Our outgassing rate is 37.5 times higher than the required (4.00E-10 Torr L/s per E080177)
• See image attached for the spectrum and the hydrocarbon (HC) tracer masses used to evaluate outgassing
• All codes and data are stored in Vacuum git repo . I'll qrite up an instruction to use the code and post it on our wiki page.

After finishing with Ar cal leak test, we close Ar valve, disconnect and turn off RGA. The He tank is moved back to the wall mount. The chamber is ready for baking installation