Secondary electron mutiplier SEM-7M

As a part of scientific or industrial equipment, SEM-7M is intended to detect corpuscular and electromagnetic radiation. Secondary electron multiplier (SEM-7M) is used as a part of time-of-flight spectrometers. SEM-7M consists of two microchannel plates stacked with gap in chevron configuration. SEM body is metal-ceramic, soldered.

PDF SEM-7M
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Secondary-electron multiplier SEM-7, intended for application in time-of-flight mass-spectrometry, is modernized. MCP 25-12F was replaced with MCP 25-10F, which allowed providing improved resolution and gain uniformity. Single electron amplitude resolution is 60%.

  • Rise time 1,3÷1,4 ns.
  • Time of flight 3÷3,2 ns.
SEM-7M's view
 

 
Circuit diagram
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Physical Characteristics

Parameter

Dimension

Value

Maximum diametermm50
Heightmm10
Input window areacm25
Key Characteristics

Parameter

Dimension

Maximum

Minimum

Gain--×107
Operating voltageV2800-
Amplitude resolution%70-
Dark count rate densitypulse/s-1× cm-23-
MCP currentµA251
Weightgrammes25-

Used types of MCP:

  • 25-10 F with figured evaporated contact electrode;
  • 25-12 F with figured evaporated contact electrode.
MCP Parameters

Parameter

Dimension

Value

Active diametermm25
Channel diameterum10; 12
Bias angledegree7; 13

MTTF not less than 1000 hrs.

There are 8 SEM modifications:

with MCP 25-10 F:

  1. with a grid in controlling electrode and with metal anode;
  2. with controlling electrode and with metal anode;
  3. with a grid in controlling electrode (without anode);
  4. with controlling electrode (without anode);

    5. with MCP 25-12 F:

  5. with a grid in controlling electrode and with metal anode;
  6. with controlling electrode and with metal anode;
  7. with a grid in controlling electrode (without anode);
  8. with controlling electrode (without anode).
SEM-7M single electron distribution
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