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Vacuum Test Facilities

MSSL have comprehensive thermal vacuum and cryogenic vacuum facilites used for qualification and acceptance testing of flight hardware. Details of these facilities can be obtained by clicking on the relevant tabs below.

MSSL 1 meter thermal vacuum test chamber

The MSSL thermal vacuum test facility can also be configured as a low energy electron calibration chamber. The latter configuration is for sole use by MSSL projects. When configured for thermal vacuum tests the facility is available to other research groups and commercial establishments.

The system is housed in a cylindrical stainless steel vacuum chamber which is 1.1m long and 1.0m in diameter manufactured by Leybold. The chamber is pumped to pressures below 5x10-7 mBar by a combination of a rotary pump, a turbopump and a helium cryopump. The electron calibration facility is housed inside a grounded mu-metal shroud inside the chamber, enclosed at both ends. This ensures that the residual magnetic field inside the chamber is less than one tenth of the Earth’s magnetic field, which results in an electron beam divergence of less than 1o at 1keV. The mu-metal shroud is 0.7m long, 0.6m wide and ~0.6m in height.

Specifications

Dimensions: 1m diameter by 1.1m long.

Electron beam diameter: 110 mm

Electron beam energies: 30 eV to 20 KeV

Base vacuum pressure: 5 x 10-6 mBar.
Temperature range (shroud): -40o C to +80o C.

Temperature range (platen): -140o C to +100o C.

Temperature control: Closed loop PID control, +0.5o C -0.5o C.

Temperature measurement: 4 wire 1/10 DIN PT100 sensors, 8 sensors total.

Temperature and pressure logging: 8 channel plus pressure logging, user set logging interval.

Electrical feedthroughs: Various D-Sub connectors and high voltage connectors (contact us for more detail)

Status

Nominal, in use by ChaPS for TechDemoSat.

20 kelvin cryostat with the outer top hat removed exposing the inner top hat and 15 layer multi layer insulation

The MSSL 20 Kelvin vacuum cryostat is a multi shroud design. The vacuum cryostat is 900 mm long by 600 mm diameter and comprises of:

  • Outer stainless steel (type 304) chamber
  • An outer electroless nickel plated aluminium chamber
  • An outer G10 chamber
  • An inner electroless nickel plated aluminium chamber
  • An inner G10 chamber
  • An electroless nickel coated aluminium chamber which houses the flight hardware
  • A pulse cooler with extended cold head
  • A single piece construction gold coated copper strap which acts as an interface between the pulse cooler cold head and the instrument mounting base
  • An inner and outer beam CaF2 input/output window system designed to minimise the external environment influences
NIRSpec CAA being installed in the 20 Kelvin vacuum cryostat

This type of chamber design allows for efficient thermal de-coupling of the external environment to the flight harware instrument mounted in the cryostat.

Specification

Dimensions: 1m diameter by 1.1m long.

Hardware mounting area: 0.4m diameter by 0.6m height
Base vacuum pressure: 5 x 10-5 mBar.
Temperature range: 20K to 360K

Temperature control: Closed loop PID control, +0.2K -0.2K.

Temperature measurement: Eight Cernox sensors.

Temperature and pressure logging: 8 channel plus pressure logging, user set logging interval.

Electrical feedthroughs: Various Micro D-Sub connectors

77 Kelvin vacuum cryostats

77K cryostat upper chamber being installed

The MSSL vacuum cryostat is mainly used for testing/characterisation of flight CCDs. The cryostat consists of an outer stainless steel vacuum vessel with an inner stainless steel liquid nitrogen (LN2) vessel mounted within the outer vessel. Thermal isolation between the inner and outer vessels is achieved by using Torlon 5030 thermal stand off spacers.This configuration ensures minimal external environment impact on the boil off rate of the liquid nitrogen and instrument under test. With CCDs and associated electronics mounted in the cryostat the liquid nitrogen vessel will allow for continuous instrument testing for twelve hours without the need to refill. Re-fill of the liquid nitrogen vessel can be performed at any time during testing which makes it possible to carry out lengthy test runs without the need to stop or re-configure the chamber.

Specifications

Dimensions: 0.45m diameter by 0.8m (H).

Hardware mounting area: 0.4m diameter by 0.6m height
Base vacuum pressure: 5 x 10-5 mBar.
Temperature range: -150oC  to +80oC

Temperature control: Closed loop PID control, +0.2o C -0.2o C.

Temperature measurement: 8 x 4 wire PT100 sensors.

Temperature and pressure logging: 8 channel plus pressure logging, user set logging interval.

Electrical feedthroughs: Various D-Sub connectors

Status

Nominal, under vacuum

Vacuum bakeout facilty and control system

The MSSL vacuum bakeout facility is a stainless steel construction chamber with oil free vacuum pumping systems. The bake out chamber has both radiative and conductive heating elements to ensure even heating of hardware in the vacuum volume.

Specification

Dimensions: 390 mm (Dia) x 750mm (H)
Max temperature: 150°C
Base Vacuum pressure: 5 x 10-7 mBar
Temperature control accuracy: ± 2°C
# of temperature sensors: 4 chamber + 2 shroud
Temperature ramp rate: 0.10 to 5 °C per minute
Temperature logging: Yes, 8 channel plus vacuum pressure
Turbo pump: Seiko Seiki STP400 MagLev

Backing pump: Scroll pump
Vent gas: Zero Grade Nitrogen (0.5 micron filtered)

Outgassing monitoring

RGA: 1 to 200 AMU, MKS Spectra Microvision plus
TQCM: 15 MHz faraday + controller and logging

Page last modified on 09 sep 11 11:29