Secondary electron multipliers SEM-6M and SEM-6С

Channel secondary electron multiplier SEM-6 with electrostatic electron focusing and open input is intended for charged / neutral particles, UV and X-ray radiation registration.

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Epoxy glue was excluded from manufacturing process of SEM-6M, intended for application in time-of-flight mass-spectrometry. Construction of the secondary-electron multiplier is entirely mechanical. Dark pulses are reduced. It is possible to use SEM-6М under 300ºС.

There are two modifications SEM-6:

  • SEM-6M / mechanical mounting to housing;
  • SEM-6C / glued joint to housing.
SEM-6M's view
Dimensional outlines
Electrical Characteristics





Gain at ≤ 3300 V-1×108-
Pulse height resolution at count rate up to 1×104cps and at U equal to gain 1×108--0,5
Dark count ratecps-0,5 *
Channel supply current at 4000 VµA520

* The measurements are made in integral mode at discrimination level 0.1 from average SEM pulses height, at U corresponding to the gain not less than 1×108.

Electrical Characteristics Changeable at Operational Process



Value, maximum

Pulse height resolution-0,8
Supply voltage amplification at gain 1×108%15
Absolute Maximum Ratings



Value, maximum

Supply voltageV4000*
Average output currentµA1**
Count ratecps105**

* In order to increase gain operation at supply voltage higher than 4000 V is allowed. In such cases discrepancies in some parameters mentioned in specification (dark count rate, pulse height resolution and mean time to failure) may take place.

** Within not more than 30 minutes.

SEM must be operable after vacuum baking at 200°C at residual pressure not better than 1.33 × 10–3Pa (1×10–5 Torr.) during 5 hours. Net weight mustn’t be greater than 30 grammes.

Precious metals content per one product

Silver – 0,2750 gramme contains electroconductive past composition.
SEM component parts don’t contain nonferrous metals.

Circuit diagram
SEM-6M single electron distribution


Warranty period: 4 years from the acceptance date.
Warranty life: providing specification terms and conditions, within the warranty period is 500 hrs.
SEM c-percentile storageability time at γ = 90%, providing storage conditions mentioned in specification is not less than 4 years.