The instrument is primarily useful for the vacuum leak testing of UHV components, chambers, enclosures, vacuum sealings, large experimental facilities etc. The basic principle involves three different components viz., an ionization source along with suitable ion-optics, mass analyzer and ion detector- all supported by suitable electronics and vacuum. The job under investigation for leak is connected with the leak detector. Helium is sprayed on the suspected parts and enters through the leak into the detector spectrometer. The helium ions are generated by electron impact which are accelerated, focused and deflected by a magnet analyser to the Faraday collector. The ion current so collected is measured and calibrated to indicate the leak rate of Helium to establish the presence and also level of the leak. It is a highly reliable and widely used method for leak testing applications.

1. Measurement range : 10(-4) torr-l/s to 10(-10) torr-l/s & 10(-7) torr-l/s(sniffer)
2. Response time: ~ 1sec
3. Modes of operation: Vacuum, Sniffer
4. Fully automatic operation

1. For leak measurement of vacuum components used in accelerators, analytical instruments, various plants using gaseous system, pressure chambers etc.

GENERAL

Dimension	700 mm (L) x 500 mm (W) x 1000 (H)
Dimension	700 mm (L) x 500 mm (W) x 1000 (H)
Test Connection	25 ISO KF
Main Voltage	220 V
Mains Frequency	50 Hz
Mains Current	< 10 A
Power	< 1 kW

Ion Source

Type	Electron bombardment
Filament	Tungsten Wire (5 mil diameter)
Accelerating Potential	450 volt
Geometry	Nier Type
Electron beam focusing	by permanent magnet (Field : ~ 100 gauss)

Analyser

Type	Permanent Magnet (Ferrite)
Geometry	Normal
Bending Angle	180 deg
Radius	5 cm
Magnetic Field	1500 gauss

Collector

Type	Faraday
Opening Size	3mm width x 10 mm height
Measurement system	Electrometer amplifier
Gain Resistance/th>	1 x 10(12) ohm<
Time constant	1 sec

Vacuum system

Vacuum pump (MS)	TMP with pumping speed 30 L/s
Vacuum pump (backing)	Rotary pump (Pumping speed: 5 m3/h)
Valve manifold	Aluminium make with 7 ports
Valve type	Electromagnetic
Valve leak tightness	< 1x 10(-8) torr L/s
Modes	Counter flow, Main flow, sniffer

Software

Operation	Auto start/stop, leak measurement
Mode selection	Semi automatic

RAW MATERIAL

1. Most of the components are available within the country and some components (Tungsten wire, vacuum pumps etc.) need to be imported through local agents.

INFRASTRUCTURE REQUIRED

1. Mechanical fabrication workshop with lathe machine, Milling machine, TIG welding, Insulation and HV tester.

Electronic Lab Facility for Testing Purpose

1. PCB assembly & instrument rack wiring facility.
2. Measuring instruments like 6 and 1/2 digit precision digital multimeter & Oscilloscope, Function Generator