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SPECS 2D-CCD, User Manual

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SPECS 2D-CCD User Manual Download Page 39

 

 

38 

Manual V2.docx  |  Status 10.12.2015  |  Version 1 

 

Figure 19.

 

The same situation as in Figure 2, with a 3 mm diameter entrance aperture.  

The spin detector is set to measure the polarization component directed 45° CCW 
from the energy dispersion plane in the plane normal to the PHOIBOS lens, as seen 
from the hemispherical analyzer towards the sample. 
 
In order to increase the separation between the bands, the sample was rotated 2° 
around an axis parallel to the energy dispersion plane of the analyzer. The spin resolved 
spectra obtained are shown in Figure 20. In the figure, spectra acquired after magnetization 
of the scattering target in the positive and negative direction are denoted by +μ and -μ, 
respectively. 
 
 

Summary of Contents for 2D-CCD

Page 1: ...User Manual Status 10 12 2015 Version 1 0 User Manual V1 0 October 19 2015...

Page 2: ...m SPECS User Manual 2D CCD 3D VLEED Detector Version 1 0 October 16 2015 SPECS order number reference 2100000201 2015 All rights reserved No part of this manual may be reproduced without the prior per...

Page 3: ...Conditioning the spin detector 13 3 Operation 14 3 1 Using templates to set up experiments 14 Templates for the 2D CCD 3D VLEED detector 17 3 1 3 1 1 PHOIBOS 1D Adjustment 17 3 1 2 PHOIBOS 1D DVS 17 3...

Page 4: ...range 43 6 3 Flat field correction 43 6 4 6 4 1 Bias frame or dark frame IB 44 6 4 2 Flat field frame IF 44 6 4 3 Non calibrated object exposure IR 44 Full well capacity 44 6 5 Hot pixels 45 6 6 Camer...

Page 5: ...am position of the electron gun 66 A 3 2 Adjusting the deflector rotator lens 67 A 3 3 Adjusting the beam alignment for the total intensity channel 70 A 3 4 Adjusting the beam alignment with the spin...

Page 6: ...also an Appendix that describes the initial installation of the detector This is performed by SPECS service personnel and is not a normal user task Information 1 2 The 2D CCD 3D VLEED Detector is int...

Page 7: ...t This will ensure safe transportation and speedy processing Safety 1 3 The document Safety Instructions is contained with this instrument This contains important warnings and procedures that you shou...

Page 8: ...you should ensure the following The chamber is leak free with a pressure of 10 7 mbar or lower All connection cables are removed The cameras are removed Switch off any power supplies before removing...

Page 9: ...operate the detector without a vacuum interlock If high voltage is applied to the detector while the chamber vents all CEMs and MCPs will be irreparably destroyed Electrical connections 2 3 The wirin...

Page 10: ...cus Note Exactly one of the two HSA 3500 plus units should have the 24 V switch set to on Figure 1 Connection of SPECS power supplies 2 3 2 Connecting the Focus power supplies In addition to the SPECS...

Page 11: ...me for these supplies in the context of the SPECS 2D CCD 3D VLEED Detector Caution Make sure the connectors on the rear of the spin controller power supply are all fitted to the correct outputs The ca...

Page 12: ...r 2 5 For degassing the electron multiplier in the spin detector please refer to the Focus Ferrum Spin Detector manual The following describes the procedure for degassing the CCD detector The CCD dete...

Page 13: ...e PHOIBOS CCD device and select the Calib Voltages tab 6 Open the Live Image View to observe the output from the camera during degassing Select Views Live Image View from the menu bar Click Activate i...

Page 14: ...ual V Udet target V Uscrn actual V Uscrn target V 600 0 0 0 1000 1800 0 1000 1000 0 4000 1000 1000 0 2000 4000 1000 1500 2000 2500 2 4 Conditioning the spin detector Following the bakeout you need to...

Page 15: ...other is simply a matter of selecting the analyzer in the software Note Before taking measurements you need to be sure that SpecsLab Prodigy is correctly configured to use your excitation source e g...

Page 16: ...in the Load Template section The following example shows the UPS Spin Step Profile template Figure 4 Selecting a template 8 Most of the settings in the template do not need to be changed before you st...

Page 17: ...just below the Description field and select Save As Template A dialog will open so that you can give the template a suitable name The template will appear in the main screen when you start SpecsLab P...

Page 18: ...you need to increase the detector voltage to compensate See the Focus Ferrum spin detector manual for more information about life time and ageing of the CEMs Caution Do not set the detector voltage t...

Page 19: ...vices 1 UV Dummy Provides the operating parameters for the excitation source 11 PHOIBOS Spin Controls the analyzer This includes the setting for the rotator 1 or 1 12 Magnetic Pulse Control Allows you...

Page 20: ...he Ferrum spin detector Sleep When you start the experiment the devices are initialized In particular charging the magnetic pulse controller and magnetizing the target takes some time The sleep item m...

Page 21: ...offers the means to change the appearance of the data as well as a number of data operations to process the data The following sections contain information about some features that are relevant to th...

Page 22: ...This is the same as the name shown in the Experiment Editor Summation Cycle You can leave this setting as Loop If a loop is used for a number of iterations of the experiment this is taken into accoun...

Page 23: ...u bar The Image View will open 2 Double click the spectrum in the data browser to select it A tick will appear next to the name of the spectrum 3 Click the label in the Y axis and select a parameter S...

Page 24: ...300 works correctly any problems with the channel are likely to come from the CEM To check the operation of the PCU 300 1 Disconnect the two BNC signal cables from the PCU 300 2 Start a scan in Specs...

Page 25: ...es between channels Note that the total intensity channel 1 of the Ferrum detector is read by the PHOIBOS 1D analyzer and that the spin channel 2 is read by the PHOIBOS Spin analyzer To set the discri...

Page 26: ...hat the preamplifier is working correctly as described in section 4 1 Check the grounding of the analyzer If the checks above do not solve the problem you can set a higher discriminator threshold sett...

Page 27: ...in Table 3 7 Select the Calib Settings tab 8 Set the remaining values in Table 3 9 Click Activate 10 Expand the view to see the set and actual voltages Check that the set and actual voltages agree The...

Page 28: ...ent There should flow 178 6 mA from pin 1 to pin 2 with RotL set to 1 and 178 6 mA with RotL set to 1 4 5 Capacitances In order to check the integrity of the lens system the capacitances to ground vac...

Page 29: ...tances for the 2D CCD 3D VLEED detector Pin Spin Lens Spin Adapter Spin Deflector Use Capacitance pF Use Capacitance pF Use Capacitance pF 1 SL1 58 SL4E 40 SL4B C 68 2 SL2Xp 28 SL6Xm 32 3 SL2Xm 28 SL6...

Page 30: ...zer lens and hemispherical analyzer for energy resolution At the exit of the hemispherical analyzer the electrons enter a lens system which contains a magnetic rotator lens This lens rotates the trans...

Page 31: ...hich started with different kinetic energies at the sample The software compensates for this effect so that the energy scale for each detector is correct 5 1 2 Acceleration lens The acceleration lens...

Page 32: ...g the z axis Bz is the z component of the magnetic field and g the gyromagnetic ratio g 2 00232 v is the relativistic velocity of the electrons e the electron charge and m the electron mass The kineti...

Page 33: ...al trajectories are equivalent for both 45 and 45 degrees spin rotation 90 deflector 5 2 The spin polarization vector S does not change in an electrostatic field An electrostatic 90 deflector can thus...

Page 34: ...the scattering target If the Ferrum detector is oriented as shown in Figure 13 this means that by magnetizing with coil 1 it will detect the spin polarization component normal to the sample surface T...

Page 35: ...CCD detector and the total intensity channel of the FERRUM detector The active area of the CCD detector was set to 38 48 mm2 so that it is equal to the area of the 7 mm diameter entrance of the spin...

Page 36: ...losses It serves as a counter and preamplifier The PCU 300 is a SPECS design The Focus Ferrum Spin Detector manual describes a different design You should bear this in mind when reading the Focus Fer...

Page 37: ...art of the valence band region Figure 17 The surface states of graphene on Ir 111 The sample is positioned at close to normal emission in the energy dispersion direction and about 3 6 off normal in th...

Page 38: ...mode LAD pass energy 20 eV The spin detector integrates the signal over the angle range indicated in Figure 18 By using a circular hole as entrance aperture or by using the iris aperture of the PHOIBO...

Page 39: ...plane normal to the PHOIBOS lens as seen from the hemispherical analyzer towards the sample In order to increase the separation between the bands the sample was rotated 2 around an axis parallel to t...

Page 40: ...and a pass energy of 20 eV The entrance aperture was 3 mm diameter The acquisition dwell time was 0 2 s and 10 scans were measured for each polarization direction The total acquisition time was 12 min...

Page 41: ...Figure 21 The asymmetry calculated from the spectra shown in Figure 20 The polarization P is calculated as where S is the Sherman function For the FERRUM detector S 0 29 is a typical value The compone...

Page 42: ...41 Manual V2 docx Status 10 12 2015 Version 1 Figure 22 The component spectra...

Page 43: ...e a convenient method for comparing images and data generated by different cameras This is also referred to as count and digital number Pixel voltages numbers of electrons stored during CCD integratio...

Page 44: ...the dynamic range is a function of the dwell time as well To be able to fully exploit the dynamic range the ADC has to have sufficient bit depth the number of bits in each pixel Cameras with a high dy...

Page 45: ...t for any variation in illumination over the field of the array The optical system most likely introduces some variation in the illumination pattern over the field of the array The flat fielding proce...

Page 46: ...t star like points There might be a few bright hot pixels more intermediate pixels and lots of very faint ones though an entire spectrum of brightness Faint hot pixels contribute to the noise in a pic...

Page 47: ...other radiation including UV VUV and soft X ray photons and even neutrons The MCP offers many advantages over conventional detectors compact and lightweight good timing properties due to short length...

Page 48: ...vacuum obtained from a roughing pump 10 3 mbar is sufficient The vacuum must be oil free 6 10 2 Operating voltage The test report supplied with the detector includes the correct operating voltage Exc...

Page 49: ...he MCPs Shipping containers should be opened only under class 100 laminar flow cleanroom conditions When handling MCPs always wear clean talc free class 100 clean room compatible vinyl gloves No physi...

Page 50: ...after glow the emission of photons after operating at brightness levels suitable for human vision After glow effects are reduced due to the selection of the standard phosphor type P 43 Gd2O2S Tb This...

Page 51: ...s the two photon photoemission signal of the image potential states n 1 2 and n 3 from Cu 100 at 300 K The surface was analyzed using a PHOIBOS 150 analyzer Frequency tripled pulses from a Ti Sapphire...

Page 52: ...6 shows the quantum well state of 12 monolayers of Pb on Cu 111 evaporated at 110 K and annealed afterwards The surface was measured using a PHOIBOS 100 analyzer and the TGM 4 monochromator at the BES...

Page 53: ...52 Manual V2 docx Status 10 12 2015 Version 1 Figure 26 Quantum well state of 12 ML Pb Cu 111...

Page 54: ...section describes the features on the rear panel of the HSA 3500plus Spin 7 1 1 Filter box connectors There are three large connectors that lead to the filter boxes for the lens adapter and deflector...

Page 55: ...ply is required If the 24 V switch on the other HSA 3500plus is already set to On you should set this switch to Off 7 1 4 Interlock The pinout of the connector is shown in Figure 28 The interlock is s...

Page 56: ...onfig 0_101_156 hsa if the HSA 3500plus for the PHOIBOS is hardware type 101 The table below lists the modules installed in the power supply Figure 29 shows the internal wiring of the unit For further...

Page 57: ...56 Manual V2 docx Status 10 12 2015 Version 1 Figure 29 Wiring diagram for hardware type 156...

Page 58: ...lens Power supply for the camera CCD diode box Alignment camera in camera holder Power supply HSA 3500plus PCU 300 Ferrum pulse counting unit FOCUS Ferrum spin detector control unit FOCUS magnetic pul...

Page 59: ...detector supplied by the FOCUS company A 2 Assembling the detector The detector is split into two parts for transportation as shown in Figure 30 Figure 30 The detector separated in its two parts Left...

Page 60: ...l damage the detector Caution Do not open the smaller flange which holds the Ferrum detector to the adapter flange the flange is labeled Do not open If this flange is opened rewiring of the detector i...

Page 61: ...he CCD deflector rotator part supported from the crane Check that the multi channel plate MCP is free from dust see Figure 33 Any dust must be removed with the air brush delivered with the detector Ca...

Page 62: ...top disc with its pin is in the correct position Mount a new CF 150 gasket Also note that it is necessary to put in some of the stud bolts before the detector is inserted into the detector port of th...

Page 63: ...CF 200 flange Before tightening the bolts check that the CF 200 flange is parallel with the plane defined by the detector and lens of the PHOIBOS see Figure 35 Figure 35 Checking the alignment of the...

Page 64: ...on the protective cap as shown in Figure 31 Check that the Mu metal screen in the pump port is in place It should look as in Figure 36 Figure 36 The Mu metal shield in the pump port of the Ferrum det...

Page 65: ...mponent hangs horizontally Check that the fingers of the Mu metal shield fits tightly into the housing of the CCD rotator deflector part The fingers can be bent slightly outwards if necessary The spri...

Page 66: ...m the crane Mount a fresh CF 200 gasket and carefully slide the adapter lens into the CF 200 flange of the CCD rotator deflector part Check that the pumping port is aligned correctly and tighten the b...

Page 67: ...ers used when the detector was tested at SPECS These factory optimized parameter values are stated in the Test Report Once the correct position of the excitation source relative to the PHOIBOS lens an...

Page 68: ...that the beam of the electron gun hits the sample on the electron optical axis of the PHOIBOS lens A 3 2 Adjusting the deflector rotator lens When you have aligned the electron gun correctly you can...

Page 69: ...tector Control in SpecsLab Prodigy Table 11 Typical parameter values for the Ferrum Detector when operated in total intensity mode Parameter Value V Scattering Energy 400 Lens 1 200 Lens 2 50 Lens 3 4...

Page 70: ...Also change the setting RotL from 1 to 1 and back The intensity should change at most 5 when changing rotation direction see Figure 43 Figure 43 The signal from the total intensity channel when Rot L...

Page 71: ...h measures the total intensity see the Ferrum Spin Detektor manual the beam alignment must also be done for the spin channel The procedure is similar to the beam alignment for the total intensity chan...

Page 72: ...nergy 6 5 Lens 1 220 Lens 2 21 5 Lens 3 415 Lens 4 49 5 Lens1DeflectorX 0 Lens1DeflectorY 0 Lens1Stigmator 0 Lens3DeflectorX 0 Lens3DeflectorX 0 Lens3Stigmator 0 Due to the geometry of the Ferrum dete...

Page 73: ...en With the RotL setting 0 a round blue spot should be visible as shown in Figure 45 Center this spot with SDefl1X and SDefl1Y It may be necessary to fine adjust the position of the electron beam on t...

Page 74: ...he image should rotate 45 as shown in Figure 47 This corresponds to a rotation of the spin polarization by 2x45 90 around the lens axis The blue stripe does not go exactly through the center of rotati...

Page 75: ...lectrons are deflected by 90 Use Ekin 20 eV Ep 160 eV and set RotL to 1 Set the aperture wheel to Slit5 open Use SDefl2X and SDefl2Y to center the beam on the screen at the exit of the 90 deflector Th...

Page 76: ...re difficult The overall procedure involves the following steps Rough adjustment of the camera angular setting Changing the Z setting for the focus Correcting the X Y position Fine tuning of the angle...

Page 77: ...camera holder 2 Hold the main body of the camera and rotate it gently The camera should be oriented so that the mounting plate is parallel to the angular adjustment screw Figure 50 shows PCO Pixelfly...

Page 78: ...he detector 4 Set the exit slits on the analyzer to B open 5 Switch on the HSA 3500plus 6 Switch on the electron gun and make sure that the sample is correctly aligned so that electrons find their way...

Page 79: ...sition A slits The image will show a number of lines 9 Turn the camera to get the position as good as possible The lines should be vertical It is sufficient to get the camera image nearly right you ca...

Page 80: ...ou need to make the following corrections Adjusting the focus in order to obtain a sharp image Centering the image in the x direction The line to the left should be at 0 mm Centering the image in the...

Page 81: ...s the optimum distance of the camera 5 Tighten the four hex bolts A 5 3 Set X Y The four hex adjustment bolts allow you to tilt the camera in the X Y directions until you see the correct alignment Thi...

Page 82: ...m scale For the Y position set entrance slit 6 1 mm diameter hole and exit slit open Adjust the Y hex bolts until the stripe is at 0 mm see Figure 54 Figure 54 Setting the Y position 4 Tighten the fou...

Page 83: ...the lines in the image are vertical You can only move a limited amount in each direction this is determined by elongated holes around the fixing bolts 4 Tighten the locking nuts 5 Tighten the fixing b...

Page 84: ...between the slits should be 8 mm If the slit slit distance is not correct the camera magnification needs to be changed See the Manual Software 2D 3D detectors for information on how to set the camera...

Page 85: ...84 Manual V2 docx Status 10 12 2015 Version 1 0...

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