CEM Handling / Mounting
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Mounting

The channel electron multipliers Series KBL are open-ended sensors, i.e. the output ends are not closed. This means that the electron avalanche generated by a primary particle must be collected at the output end of the channel in order to be able to produce an output pulse. To collect the electron avalanche, an anode is employed that is held in place with a ceramic support. The anode is a modified M1.6 screw so that a signal cable can be connected without difficulty.

A gold layer is deposited onto both ends of the CEM for electrical contacting of the CEM input and output ends to the applied high voltage. Through holes in these metalized contact area screws must be placed to which electrical wires can be attached. All necessary screws are included in delivery. Additional holes in the ceramic body permit the CEM to be mounted in any position (Fig. 1).

The ceramic anode support is screwed on to the ceramic body and affixed tightly to the rear side of the CEM. The shape of the anode support ensures that no electrons escape from this channel output into the environment surrounding the CEM, which could then ionize neutral residual gas and generate after-pulses. The gap between the output of the CEM and the anode has a width of about 0.5 mm so that they are electrically separated from one another (Fig. 2).

 

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Please note that ceramic is a material that can break under high tensile strain. Therefore, make sure to tighten the screws carefully.

 

We deliver several models with sunk-in ceramic threads (M1.7) for the electrical contacts as well as for fastening the anode support, especially with the CEM arrays (Fig. 3). These threads also enable the CEMs to be fixed onto supports.

When possible, we equip the anode support with an anti-twist device so that the anode sits directly behind the output and cannot be changed in its position (Fig. 2).

The colored outer glaze stabilizes the already relatively unbreakable ceramic of the ceramic base body of the CEM and the anode support. It is nevertheless necessary to carefully tighten the screws, since the material is not a metallic material.

When mounting the sensors in your equipment, please make sure that the gold metalization, especially in the area of the CEM input, is not damaged. Otherwise fine particles of the metalization may enter into the funnel, triggering dark pulses due to field electron emission, leading to instable operation.

 

! When mounting the sensor into your equipment, make sure to avoid damage to the metalization of the CEM input area.

 

If damage does occur, try to clean the electron multiplier (CEM Cleaning).

Fixing of CEMs in arrays

We always deliver CEM arrays with rods that hold the array together and can be used at the same time to fasten the array on an external support. The length of these rods may be selected by the customer to ensure trouble-free installation of the array.

 

 
 

Fig. 1 A simple way of mounting

 
 
Fig. 2 Attachment of the anode support
 
 
Fig. 3 Sunk-in ceramic threads (M1.7)
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


Dr. Sjuts Optotechnik GmbH

Am Schlehdorn 1, 37077 Goettingen, Germany Tel. + 49 (0) 551 209 95 62, Fax. + 49 (0) 551 209 95 63, Email: sjuts@t-online.de