It is very important to have snap estimation of energy of  incident ions flux for many technological applications especially for precision ion sputtering equipment. 

PROBE SET provides measurement and analysis of beam characteristics in the range up to 3,0 keV.  PROBE SET is designed for work under intense ions flux.

BACKGROUND

• Three-electrode electrostatic analyzer is used as ion beams probe.
• Basic sketch of three-electrode analyzer is shown below.

The main idea is to stop ions flux by applying repellent potential  UC  to COLLECTOR (C).

Only ions that have energy higher than eUC can overpass this electrostatic barrier.

It is possible to analyze energy fractions of ions by varying UC  and measuring COLLECTOR (C) current. 

The dependence of ions current from COLLECTOR  (C)  vs. potential UC  is a Stopping Characteristic of ion beam.

But it is need two additional grid electrodes for proper ions analysis. 

Input Grid (G1) has a potential  UPL  that is close to plasma potential in PROBE location as shown at figure. This electrode protects a plasma from disturbance due to high COLLECTOR (C) potential UC. 

Rejection Grid (G2) separates ions from compensated beam rejecting electrons  by  negative (relative to G1) potential  UG2.

PROBE SET  DESCRIPTION    

PROBE SET includes:

1. PROBE

General View and Overall Dimensions are presented on figure above.

Stainless Steel and Ceramics are materials for main parts of  PROBE.

Input Grid (G1) and Rejection Grid (G2) can be replaced with eases.

PROBE SET  includes spare Grids and reserve Collector to PROBE.

PROBE is fitted out by  ATTENUATOR to measure in high intensity beams.

It is easy to adjust a PROBE sensitivity by combining with reducing Attenuator Grids  (AG) and/or Diaphragms (D).

2. CABLE

Two-wire shielded flexible CABLE connects the PROBE to CONTROL UNIT.

The CABLE is equipped by VACUUM FEEDTHRU.  

The FEEDTHRU can be mount on vacuum chamber  via  18mm hole on flat vacuum wall or flange. 

• The length of vacuum-side portion of the CABLE  is approx  1 m.  
• This part has an outer armouring shield.
• The length of another portion of the CABLE  is more than 3 m.

3. CONTROL UNIT

The control unit generates analyzing voltage Uc with positive polarity that supplying to probe's collector via cable connected to unit through the coaxial HV connector. The collector voltage is varying in manual or automatic modes in the range 50-3000V.

The control unit generates DC negative voltage supplying to rejection grid of the probe via the cable connected through multipole connector.

The control unit measures ion current by amlifieramplifier with digital adjustable gain and sends current and collector voltage data through digital interface to PC-compatible computer.

The control unit is controlled be digital interface from PC-compatible computer.

The control unit provides a some levels of protection for safety and long-duration work.

Front View of UNIT is shown on figure.

4. INTERFACE CABLE

The INTERFACE CABLE connects The CONTROL UNIT to any free LPT port of PC.

Total length is 1,5 m.  DB15F to DB25M type.

5. COMPUTER

6. SOFTWARE

The program PROBE DAM provides operation of the probe set.

The software controls the process of measurement and data acquisition of stopping characteristics and provides post-processing for obtaining ions energy distribution function.

After start PROBE DAM program from Windows Start Program Menu  the main window appears as shown on figure. 

Now everything is ready to accumulate, visualize and save data. 

Push START  button.  Stopping Characteristic will be drawn on the screen as UC rises due to automatic mode CONTROL UNIT.  Working values of UC and ion current are displayed on LCD-like indicators at the left side of program window also.

Push STOP button - the data will be saved in file.

Need a Spectrum Analysis? Just Click ANALYSE button. 

In a few seconds Data Analysis Window with Normalized Energy Distribution Curve will appear.  

You can save this Curve as BMP file.

Questions? Comment? Mail to tsyg@power.bmstu.ru

PROBE SET SPECIFICATIONS

OPERATING INSTRUCTIONS : html | pdf

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