UHV Slit (SLT-300)

This unit consists of vertical and horizontal slit mechanisms, a double-sided flange which houses them, stepper motors, limit switches, and electrical connections for beam monitoring. Each of the four blades are individually controlled and motorized. The range of travel for each blade is from –3 mm to +30 mm depending on the size of the configuration (3 mm overlap to 60 mm opening). With modification, the blades can withstand a heat load of 5 watts. This modification precludes beam monitoring.

All models use cross-roller bearing technology for exceptional straightness of travel. All of these slits use standard micro stepped stepper motors that can be controlled with a wide array of controllers/drivers available on the market. The design incorporates limit switches. All the models come with linear encoder option. All blades can travel past each other without interference (Overlapping/Zero Beam).

• Micron precision
• Linear encoder option (see page 25 & 26)
  
• Beam monitoring option
  
• Blades can go "past closed" without clashing (Overlapping/Zero Beam)
  
• Blade material;
• Synchrotron Application:
  
  • Tungsten (TU) 95%W, 2.5%Ni, 2.5%Cu
    
  • Tantalum (TA) ASTM-B-708 RO5200

A spring-extended linear encoder with built-in home position is provided for each individual blade. The accuracy of the linear encoder is +/-1 micron. An easily visible linear scale for each blade is attached to its translation system to provide an alternate way of reading the blade position. Limit switches and hard stops prevent damage by over-travel. The four blades are electrically conducting and insulated from the vacuum vessel. Each such blade is connected to a feedthrough with a standard BNC connector. The signal current resulting from the beam hitting the blades is in the milli- to micro-amp range per blade. The drive assembly uses stepper motor actuation and crossed-roller bearings. All UHV sections are vacuum tested to better than 5x10^-9 with an option of 10^-10 torr and have a leak rate of less than 2x10^-10 mbar 1^-1s^-1.

 

Beam Monitoring (Option)

The blades of these slits are independently, electrically isolated and have a connector and wire to enable beam monitoring. This is used to determine the position of the beam. Four independent electrical connections are used. The minimum DC resistance between the blade and earth is >10¹⁰ ohms.

 

Fiducial Marks

For beamline component alignment ADC provides fiducial marks on precision surfaces. UHV Slits, for example are shipped with precision tooling balls for component alignment.

 

Linear Encoders

The UHV Slits use the Heidenhein linear incremental encoder.

Encoders are mounted outside the UHV. Each encoder will have 1 meter cable length. The Stepper motors that drive the blades are size 23, 6 wire motors. They are EAD Motors PN LA23GCKJ-210-4. 4 volt, 1.54 amps. These are linear actuator motors which means the lead screw nut is integral to the motor and is driven directly, there is no coupling between motor and lead screw.

Two limits are provided on each axis for +/- limits, wired normally closed. A plastic CPC connector is provided with each axis for motor and limit connection. Pin outs are available on request. Linear encoders have a separate connector.

Encoders (If Specified) for SLT-300-10 and SLT-300-20

 

Encoders (If Specified) for SLT-300-30 and SLT-300-40

 

ORDERING INSTRUCTIONS:

UHV Slits can be ordered with different options. Please use the following chart for ordering.

 

For example: To order an SLT-300-10 Slit with encoders, tungsten blade, with the ability to monitor the beam and RGA, the model number would be - SLT-300-10-E-TU-B-R

Note #1: Custom/Neutron application blades are available in boron carbide, cadmium, boron nitride or a sandwich combination structure.