Introduction... 3 Slits for AIR Operation... 4 Slits in Vacuum Vessels... 5 Slits for High Vacuum Operation... 6 Custom Slits... 7 Steel Slits... 10 Non-magnetic Options for Slits... 12 Slits with Passive Cooling... 13 Slits for UHV Operation... 15 Slit Blades... 18 Slit Blades Quality... 21 Water Cooled Slits... 23
Over the last two decades, JJ X-Ray has delivered high precision slit systems to neutron and x-ray facilities all over the world. During the years, our portfolio has expanded significantly, to meet our customers needs. In this catalogue, we will present the large variety of our slit systems. For more details on specific sizes or other custom needs, please contact us directly by e-mail or visit our website. Basically, our slit systems are defined by blade motion, position of aperture, maximum aperture and slit operation environment. Blade motion: Individual Blades (IB) or Aperture Translation (AT) Position of Aperture in slit body: Centered (C), Off-Center (F), Asymmetric (A) Maximum Aperture Opening in mm Slit Operation: In air (AIR), in high vacuum (HV) or in ultra-high vacuum (UHV) Using this naming convention, our slits are named according to the following system: In addition to the above functionalities, we offer a wide range of options: Cooling, drain current, non-magnetic solutions, custom blades, encoders and DEMI-slits (a 2 blade slit) etc. In other words, we will do our best to meet all you specifications. 3
The AIR-slits represent a large variety of systems that are optimized to operate in air, and the materials are carefully chosen for their mechanical and radiation resistant properties. Our classic AT-F7-AIR slit developed by ESRF engineers and scientists. Two identical houses and a off-centered aperture. ATslit blades are translated in pair by one common motor, and the aperture is controlled by another motor. Also available in a vacuum version (AT-F7- HV). IB-C120-AIR has a large centered aperture and is typically used by neutron facilities. Four independently moveable blades defines the aperture size and position. 4
Many customers need to insert their slit systems inside larger vacuum vessels. In these cases, you will not need a slit system with flange connections (see our "Vacuum Slits") but rather a modified "AIR Slit". Occasionally, a beamline has extra sensible components such as mirrors or detectors in close vicinity of the slits. In these cases, extra precautions may be needed to avoid contamination. Depending on your vacuum pressure and instrumentation, you can either go all the way and have an AIR Slit for UHV or you can replace some of the critical parts in our standard AIR Slits. This is a modified version of our standard IB-C50-AIR. All parts and surfaces are suited for UHV operation (including microswitches, motors, wiring, connectors, guides and encoders). 5
Thousands of high vacuum JJ-slit systems are operating successfully at a large variety of neutron and synchrotron beamlines all around the world. They consist of low outgassing materials and are o-ring sealed. The systems are developed for 10-5 mbar vacuum operation and a significant part of these are also prepared for operating at vacuum lower than 10-5 mbar. AT-C8-HV is our most compact vacuum slit. It has a centered aperture and KF-25 flange connections. The blades are translated in pair by one common motor, and the aperture is controlled by another motor. IB-C30-HV has a 30x30 mm 2 aperture and is fitted with KF-40 flange connections. Four independently moveable blades defines the aperture size and position. 6
Sometimes, the limited space around the beamlines and special requirements for the aperture size makes it difficult for a standard square slit to fit into a specific instrumentation. In that case, we can design and produce a customized solution which is developed from our standard slit systems. An overview of our existing custom shaped slit designs are available on our website. IB-A30x100-AIR has a 30x100 mm 2 aperture and not fully overlapping blades. The rectangular shape makes it possible to fit it into a very compact setup. 7
A custom shaped slit system (IB-A40x60-AIR) with a base and a rectangular aperture. In addition, it contains ball screws to increase operational life. 8
2 blades slit systems : IB-A50x150-AIR-DEMI. IB-A60x100-AIR 9
Our standard slit houses are made of aluminum which is easy to process and handle. In a few cases, vacuum pressure might challenge precision and therefore, the standard aluminum house is replaced by a stainless steel house to reduce strain of lead screws and linear guides. Stainless steel is also possible where shielding of higher energies is required. Stainless steel version of AT-C8-HV. A welded steel version of IB-C150-HV. To reduce strain of lead screws and linear guides due to vacuum pressure, the standard aluminum house is replaced by a steel house. 10
FE analysis of the welded chamber for IB-C150-HV to simulate the deformation of the slit housing (15 mm thick) when it is under the influence of vacuum pressure. The pressure applied to the internal walls is -1013 hpa. The elastic modulus of SS 304 is 193 GPa. The result shows the maximum total displacement vector of 89.4 um located at the central part of the slit housing. 11
If a slit system needs to be positioned in close vicinity of a magnet, or if the beam is very sensitive to the magnetic fields, there are a range of options to reduce magnetism. IB-C160-AIR with extensions moving motors and rotary encoders 100 mm further away from the beam center. The system also contains non-magnetic guides, lead screws and screws. IB-C50-AIR with non-magnetic guides, screws and lead screws. A nonmagnetic solution, we offer for several of our larger AIR og HV slit systems. The chosen materials depends on the slit operation (AIR or HV). 12
Sometimes, the total power of the beam is slightly too high for a standard slit system. In many cases, it is enough to use passive cooling to solve the heat issue. At present, we have an AIR and HV version suitable for a heat load up to 5 Watt per blade. Thermocouples can be integrated for heat monitoring. If needed, JJ X-Ray offers heat transfer analysis to calculate the temperature based on a specific heat load. IB-C50-AIR-CL contains copper braids. In addition, ventilation holes are added to improve air circulation. IB-C30-HV-CL is sligthly larger in beam direction than the classic IB-C30-HV. This version contains copper braids as well as thermo couples. Extra connectors for the thermocouples are seen on the side of the motor house. 13
IB-C50-AIR-CL. The shown copper braids conduct the absorped heat from the slit blades to the aluminum housing. Heat transfer analysis was performed on IB-C50-AIR-CL. The beam size was calculated to 200 µm 2 and the heat source of 37.5 W was applied to the edge of the slit blades. Heat was removed from the slit blades using flexible copper braid (area = 6.0 mm 2, dimensions 10 mm x 1 mm, 0.15 mm wire dia.). The temperature on the outer surfaces of the slit was set to room temperature of 22 deg C. As a result, the maximum steady-state temperature was 162 C located at the heat source. This is acceptable for shorter periods of time e.g. during alignment. 14
To accommodate market demands for a reliable compact UHV slit (10-9 mbar for monochromatic applications), we have expanded our standard individualblade slit design into a UHV compatible slit system. Like the air and vacuum IB-slits, the aperture in the UHV version is defined by four independently movable and highly polished tungsten carbide blades. These blades are controlled by a high-precision in-vacuum guiding rail system. The guides are positioned close to the blades giving the shortest distance from the guide to the blade. We recommend the option with internal linear UHV compatible encoders in order to obtain precise knowledge about the actual blade position. Accuracy for IB-C30-UHV is ± 2 µm over 3 mm in open loop and <0.5 µm in closed loop. A large number of options can be applied to this model e.g. cooling, drain current, pin diode, alignment bases, extra view ports, custom blades and motors. 15
IB-C30-UHV with options: Pindiode and alignment base. The shown alignment base has the following motions: x and y directions, roll and pitch (Phi, Chi), and yaw (Theta). IB-C30-UHV with passive cooling option. Copper braids mounted between each blade and the steel chamber (cooled for operation up to 5 Watt per blade). Typically combined with thermocouples. The assembly of IB-C30-UHV takes place in our ISO 5 cleanroom 16
partial pressure [mbar] 1,00E-08 RGA on 10938@ 1.2E-8mbar 1,00E-09 1,00E-10 1,00E-11 1,00E-12 1,00E-13 1,00E-14 1 6 11 16 21 26 31 36 41 46 51 56 61 66 71 76 81 86 91 96 amu Summary Value Turbo Pump started pump only PrismaPlus RGA probe turned on Callibration Faraday scan SEM scan Pressure at scan time 1.4E-8 mbar Highest peak is AMU=18 1.25E-10 mbar Inteval 20 to 44 are < 1E-2 of AMU(18) Passed Inteval 45 to 100 are < 1E-3 of AMU(18) Passed Pressure integral 1.80E-10 mbar Extract from our RGA Test. In addition to RGA testing, our UHV Slits go through a detailed testing sequence in closed and open loop operation. An example of a test report can be obtained. 17
Our slit blades are carefully selected and a wide range of materials as well as configurations are possible. Most common materials are Tungsten Carbide, Tantalum, Boron Carbide and single crystal blades (Si, GaAs or InP). Slit blade shapes include knife-edge, rectangular and cylindrical shapes. For single crystal blades, we normally use a 20 degree tapered angle. Standard 2 mm Tungsten Carbide blades for IB-C30-HV with a 0.5 degree knife-edge on one side and R16 cylinder shape on the other side. X-ray facilities The rectangular blade (no knife-edge): Will give a well-defined sharp blocking of the beam, but there may be a contribution of total reflectivity of the part of the blade that is parallel to the incoming beam. If the beam is very divergent, this may not be a problem. When working at higher energies and using e.g. 10 mm thick blades, we often recommend rectangular blades. Knife-edge blade: The alternative is to have a knife-edge. Here the blocking of the beam will not be as sharp, since there will be some transmission near the edge of the knife. On the other hand, you can avoid the total reflectivity from the blade. The cylindrical shape: Will also have some transmission near the edge, and there will in addition also be some total reflectivity near the tangent of the cylinder. But used for a guard slit/clean up slit, this sometimes limit the diffuse scattering from the blades. 18
Single crystal blades: are typically used for guard slits/clean up slits. Below 8-10 kev, we recommend single crystal Silicon blades. They have been tested at 8 kev at the P10 beamline, PETRA (SAXS beamline) where scattering was reduced by a factor of 100. At higher energies (above 10 kev), alternatives such as GaAs og InP are recommended. Single crystal blades can be used for high vacuum and ultra-high vacuum on request. Standard tungsten carbide blade Single crystal Si blade 19
The cylindrical super-polished blades: Are often used for beamlines with very high beam coherence such as FEL s. The blades are often configured in two successive slits. The first slit has blades with low-z cylinders (Si 3 N 4, SiC or B 4 C) and the second slit has blades high-z cylinders (WC, TaW). The first low-z slit serves as a guard for single-shot damage of the intense FEL pulses, and the second high-z slit serves as the stopping of higher energies. Tantalum (Ta90/W10) blade holder with a nano polished Si 3 N 4 cylinder and a Si 3 N 4 sheet. The cylinder is exposed to a 10-step polishing procedure to achieve an excellent surface. Best results are achived with tantalum (Ta90/W10) and Si 3 N 4. Neutron facilities: Blades used at neutron facilities are typically rectangular and our preferred material is B 4 C (natural Boron Carbide) or 10 B 4 C (enriched Boron Carbide). Blades can either be mounted by holes or clamps. 20
By using MarSurf PS1 measuring instrument, it is possible to control parameters as straightness of blade edge and surface roughness. The parallelism of slit blades may be quantified by laser interferometry. The example on next page shows a setup with a blade parallelism of 0,04mrad. Standard 2 mm tungsten carbide blades for IB-C30-HV. Straightness of polished tungsten carbide blade edge and surface roughness are measured using a MarSurf PS1 roughness measuring instrument 21
Diffraction intensity perpendicular to slit Pixels Slit-diffraction data and measurement regions Location of diffraction - minimal and fitted slit size Order Pixel location Intensity a.u. 22
Sometimes, water cooling is a necessary option for high power beams. For this purpose, we have developed a power slit with an aperture of 50 mm and a possible absorption of 400 Watt. It is suitable for ultra-high vacuum <1x10 9 mbar. For more information, please contact sales@jjxray.dk Water cooled slit blade component IB-C50-UHV-400W 23
Slit Systems (AIR,HV, UHV) Complete Beamline Solutions Spectrometers Refractive Optics Foil Collimators Positioning Contact JJ X-Ray A/S If you have any questions, concerns, request for quotations or need general advice, please feel free to contact us: JJ X-Ray A/S Scion-DTU, Dr. Neergaards Vej 5D 2970 Hoersholm Denmark Telephone: +45 4776 3000 Fax: +45 4776 3001 VAT: DK 29523215 info@jjxray.dk sales@jjxray.dk Website: www.jjxray.dk