SPECS 2D-CCD Manuel utilisateur
User Manual | Status 10.12.2015 | Version 1.0
User Manual V1.0 | October 19, 2015
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User Manual | Status 10.12.2015 | Version 1.0
SPECS Surface Nano nalysis GmbH
Voltastrasse 5
13355 Berlin
Germany
Tel: +49 30 46 78 24-0
Fax: +49 30 46 42 08-3
Email: [email protected]
Web: http://www.specs.com
SPECS User Manual
2D-CCD / 3D-VLEED Detector, Version 1.0
October 16, 2015
SPECS order number reference: 2100000201
©2015. ll rights reserved. No part of this manual may be reproduced without the prior
permission of SPECS GmbH. Other product and company names mentioned in this
document may be the trademarks or registered trademarks of their respective owners and
are used for identification purposes only.
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Table of contents
1
Introduction ....................................................................................................................... 5
bout .................................................................................................................................. 5
1.1
Information ........................................................................................................................ 5
1.2
Safety .................................................................................................................................. 6
1.3
2
Preliminary tasks ............................................................................................................... 7
Baking out .......................................................................................................................... 7
2.1
Vacuum conditions ............................................................................................................ 8
2.2
Electrical connections ........................................................................................................ 8
2.3
2.3.1
Connecting the SPECS power supplies ............................................................................. 9
2.3.2
Connecting the Focus power supplies ............................................................................. 9
2.2
Degassing the Ferrum detector ...................................................................................... 11
2.3
Fitting the CCD camera.................................................................................................... 11
Fitting the alignment camera .......................................................................................... 11
2.4
Degassing the detector ................................................................................................... 11
2.5
2.4
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 djustment ................................................................................................ 17
3.1.2
PHOIBOS 1D DVS ............................................................................................................. 17
3.1.3
Scattering Energy Scan .................................................................................................... 18
3.1.4
PHOIBOS Spin djustment ............................................................................................. 18
3.1.5
UPS Spin Step Profile ....................................................................................................... 19
Performing CCD measurements ..................................................................................... 19
3.2
Viewing results ................................................................................................................. 20
3.3
3.3.1
Calculating the spin asymmetry ..................................................................................... 20
Using the Image View to display results ........................................................................ 22
3.4
4
Troubleshooting............................................................................................................... 23
4.1
mplifier check ................................................................................................................ 23
4.2
Discriminator threshold .................................................................................................. 24
4.3
Noise ................................................................................................................................. 25
4.4
Checking the voltages ...................................................................................................... 25
4.1.1
Detector settings .............................................................................................................. 25
4.1.2
Voltages ............................................................................................................................ 26
4.1.3
Rotator .............................................................................................................................. 27
4.5
Capacitances .................................................................................................................... 27
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Spin Detector Principles .................................................................................................. 29
Electron optics ................................................................................................................. 29
5.1
5.1.1
nalyzer ............................................................................................................................ 30
5.1.2
cceleration lens ............................................................................................................. 30
5.1.3
Rotator lens ...................................................................................................................... 31
90° deflector .................................................................................................................... 32
5.2
5.2.1
Retardation stage ............................................................................................................ 33
3D spin polarization detection ....................................................................................... 33
5.3
Spin detector lens transmission ..................................................................................... 34
5.4
VLEED spin detector ........................................................................................................ 35
5.5
PCU 300 Electronics ......................................................................................................... 35
5.6
Example of experimental results .................................................................................... 35
5.7
6
Principles of the CCD Detector ....................................................................................... 42
Camera ............................................................................................................................. 42
6.1
Linearity ............................................................................................................................ 42
6.2
Dynamic 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
Camera specifications ..................................................................................................... 46
6.7
Micro channel plates ....................................................................................................... 46
6.8
Care of MCPs .................................................................................................................... 46
6.9
Maximizing the lifetime of MCPs .................................................................................... 47
6.10
6.10.1
Storage ............................................................................................................................. 47
6.10.2
Operating voltage ............................................................................................................ 47
6.10.3
Bakeout ............................................................................................................................ 47
6.10.4
Degassing the detector ................................................................................................... 48
6.10.5
Measurements ................................................................................................................. 48
Handling MCPs ................................................................................................................. 48
6.11
Phosphor screen .............................................................................................................. 49
6.12
pplication data ............................................................................................................... 49
6.13
7
Power Supplies ................................................................................................................ 53
HS 3500plus Spin rear panel ........................................................................................ 53
7.1
7.1.1
Filter box connectors ....................................................................................................... 53
7.1.2
Rotator connector ............................................................................................................ 54
7.1.3
24 V switch ....................................................................................................................... 54
7.1.4
Interlock ........................................................................................................................... 54
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7.1.5
Other specifications......................................................................................................... 54
HS 3500plus Spin hardware type ................................................................................. 55
7.2
ppendix - Installation ................................................................................................................. 57
.1 Packing list ............................................................................................................................... 57
.2 ssembling the detector ........................................................................................................ 58
.2.1 Mounting the CCD/rotator/deflector part .......................................................................... 59
.2.2 Mounting the Ferrum detector part ................................................................................... 63
.3 Optimizing the signal .............................................................................................................. 66
.3.1 djusting the beam position of the electron gun.............................................................. 66
.3.2 djusting the deflector/rotator lens ................................................................................... 67
.3.3 djusting the beam alignment for the total intensity channel ........................................ 70
.3.4 djusting the beam alignment with the spin channel ...................................................... 70
.4 lignment with phosphor screens ......................................................................................... 71
.4.1 lignment of spin deflector 1 and the rotator lens with the alignment camera ............ 72
.4.2 lignment of spin deflector 2 with a phosphorous screen .............................................. 74
.5 Camera alignment .................................................................................................................. 75
.5.1 Rough angle adjustment ..................................................................................................... 75
.5.2 Setting the focus .................................................................................................................. 79
.5.3 Set X–Y .................................................................................................................................. 80
.5.4 Fine angle adjustment ......................................................................................................... 81
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User Manual | Status 10.12.2015 | Version 1.0
1 Introduction
Welcome to the user manual for the SPECS 2D-CCD / 3D-VLEED Detector. This detector is suitable
for performing measurements in a wide range of spin-dependent studies.
This chapter explains briefly how to use the manual and points you toward further sources of
information.
Most importantly, it contains safety notices that you should read before operating the equipment.
About
1.1
The manual is divided into the following chapters:
1. Introduction
2. Preliminary tasks
3. Operation
4. Troubleshooting
5. Spin detector principles
6. Principles of the CCD Detector
7. Power supplies
There is also an ppendix 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 intended for use with PHOIBOS 150 and 225 electron energy
analyzers. Manuals describing the operation of the PHOIBOS analyzer and its power supplies are
available as separate documents. You should consult these manuals in addition to this document
in order to achieve safe and reliable operation.
Note that mounting the 2D-CCD / 3D-VLEED Detector imposes the following limitations to the
performance of the PHOIBOS analyzer:
• The maximum kinetic energy, E
kin
is 1500 eV.
• The maximum pass energy, E
p
, is 200 eV
• Ions cannot be detected
For further advice and assistance, please also contact SPECS support:
Tel. +49 30 46 78 24-0
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User Manual | Status 10.12.2015 | Version 1.0
If you need to return this SPECS product for repair, service or upgrade, please first contact SPECS
support. We will provide you with an RM as well as details for correct packaging and shipment of
the instrument. 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 should adopt when using SPECS equipment.
Danger—High Voltages Present!
Do not operate the instrument without cables correctly connected. Ensure that cables are not
worn or damaged. Only qualified personnel using appropriate equipment should perform repair
work.
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2 Preliminary tasks
Before using the detector, you need to perform standard procedures so that the detector is ready
for use.
Note
Initial installation and alignment is performed by SPECS engineers on delivery of the instrument.
These procedures are provided for reference in the ppendix of this manual.
This chapter describes the following:
• Bakeout.
• Suitable vacuum conditions for operation.
• Conditioning the Spin detector .
• Electrical connections.
• Fitting the camera for the CCD detector.
• Degassing the detector.
aking out
2.1
In order to achieve UHV, you need to bake out the chamber. Before baking out, you should ensure
the following:
• The chamber is leak-free with a pressure of 10
−7
mbar or lower.
• ll connection cables are removed.
• The cameras are removed.
Switch off any power supplies before removing cables.
The maximum bakeout temperature for the 2D-CCD / 3D-VLEED Detector is 150°C. You should
attach a thermocouple to the detector flange to monitor the temperature during bakeout.
Note
Remember to observe the maximum bakeout temperature for all other instruments on the
chamber!
fter baking out, the analyzer needs two days to cool down in order to protect the working
surfaces of the detector. The interior parts of the PHOIBOS will cool down significantly more
slowly than the casing. You should wait until the detector assembly has cooled down completely—
this takes approximately 2–3 days.
Caution!
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Even if the analyzer casing just feels warm, any internal parts seated on insulators may still be too
hot for safe operation. ll users should be aware of this issue and take the necessary precautions.
Vacuum conditions
2.2
lways observe the following points in order to protect the detector:
• void backstreaming from oil diffusion pumps or roughing pumps at all costs. When
using such pumps, you should use cold traps and molecular sieve traps. Make sure these
are correctly maintained.
• Operate the detector in a clean vacuum environment of 5 × 10
−8
mbar or better in order
to ensure the longevity of the detecting surfaces. The detector can be degraded by
exposure to various types of hydrocarbon gases which raises the work function of the
surface and hence causes gain degradation.
• Do not allow gases containing F, S and Cl to enter the detector area, as they may
decompose under electron bombardment.
Caution!
Do not 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 wiring scheme for the 2D-CCD / 3D-VLEED Detector is complex and involves several power
supplies. To make the wiring scheme easier to understand, it is divided into two parts, which are
described in the following sections.
Please note these general points for the electrical connections and power supplies:
• There is a ground screw on the rear of the power supplies which should be attached to a
central earthing point by a low resistance earthing strap.
• The power supplies should be fitted into a rack or installed on a flat, stable surface.
• Make sure the equipment is protected against high pressures by interlocks. Do not
defeat the interlocks during operation.
The 2D-CCD / 3D-VLEED Detector requires several power supplies for its operation:
• Two SPECS HS 3500plus units for the CCD detector and the rotator.
• Three Focus units for the spin detector, evaporator and coil magnetization.
The following figures show all electrical connections for the 2D-CCD / 3D-VLEED Detector.
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2.3.1 Connecting the SPECS power supplies
Figure 1 shows the connection diagram for the SPECS electronics. With the exception of the
detector output signals, all connections for the Ferrum detector are provided by power supplies
from Focus.
Note
Exactly one of the two HS 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 power supplies, there are also three power supplies from Focus, which
are used for operating the spin detector and its accessories:
• Ferrum Spin Detector Control Unit — supplies the voltages for the Ferrum spin detector
L4E
Ref
Ferrum Spin
Detector Controller
Ref in
Slit in
Diode box
Ce manuel convient aux modèles suivants
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Table des matières
