CPC 125/65 M Channeltron Pulse Counting Electronics

Transcription

1 CPC 125/65 M Channeltron Pulse Counting Electronics for EA 125 and AR 65 Version 2.0 March15, 2000 M Limburger Straße 75, Taunusstein, Germany Tel.: +49 (0) , Fax: +49 (0)

2 Preface 2 CPC 125/65 M Copyright The information in this document is subject to change without notice and does not represent a commitment on the part of OMICRON Vakuumphysik GmbH. No liability shall be accepted for any damages resulting from the use of this documentation and the related product. Please note: Some components described in this manual may be optional. The delivery volume depends on the ordered configuration. No part of this manual may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying and recording, for any purpose without the express written permission of OMICRON Vakuumphysik GmbH. Channeltron is a registered trademark of Galileo Electro-Optics Corporation. Other product names mentioned herein may also be trademarks and/or registered trademarks of their respective companies. Please note: This documentation is available in English only. Attention: Please read the safety information on pages 6 and 7 before using the instrument. Related Manuals EA 125 Analyser or AR 65 Analyser EAC (-65) Control Unit EAC (-65) Control Unit EIS Software Manual ComputerBoards GPIB Manual Table 1: Related manuals.

3 Preface 3 CPC 125/65 M Contents List of Figures... 3 List of Tables... 3 Conditions of CE Compliance Introduction... 5 Normal Use Safety Information Preamplifier Multiplier Supplies Optical Receiver Trouble Shooting Service Procedure Useful OMICRON Contacts Index List of Figures Figure 1: Preamplifier schematic circuit diagram... 8 Figure 2: Multichannel preamplifier with cover removed, example Figure 3: Multiplier supplies unit, multi-channel version Figure 4: Location of the HV adjustment potentiometers Figure 5: Fibre optic receiver. Block diagram of one channel Figure 6: Receiver with 5 channels fitted, schematic diagram List of Tables Table 1: Related manuals Table 2: Preamplifier jumper settings... 8 Table 3: Optical receiver jumper settings

4 Preface 4 CPC 125/65 M Conditions of CE Compliance OMICRON instruments are designed for use in an indoor laboratory environment. For further specification of environmental requirements and proper use please refer to your quotation and the product related documentation (i.e. all manuals, see individual packing list). The OMICRON Channeltron Pulse Counting Electronics complies with CE directives as stated in your individual delivery documentation if used unaltered and according to the guidelines in the relevant manuals. Limits of CE Compliance This compliance stays valid if repair work is performed according to the guidelines in the relevant manual and using original OMICRON spare parts and replacements. This compliance also stays valid if original OMICRON upgrades or extensions are installed to original OMICRON systems following the attached installation guidelines. Exceptions OMICRON cannot guarantee compliance with CE directives for components in case of changes to the instrument not authorised by OMICRON, e.g. modifications, add-on's, or the addition of circuit boards or interfaces to computers supplied by OMICRON. The customer is responsible for CE compliance of entire experimental setups according to the relevant CE directives in case of installation of OMICRON components to an on-site system or device (e.g. vacuum vessel), installation of OMICRON supplied circuit boards to an on-site computer, alterations and additions to the experimental setup not explicitly approved by OMICRON even if performed by an OMICRON service representative. Spare Parts OMICRON spare parts, accessories and replacements are not individually CE labelled since they can only be used in conjunction with other pieces of equipment. Please note: CE compliance for a combination of certified products can only be guaranteed with respect to the lowest level of certification. Example: when combining a CE-compliant instrument with a CE 96-compliant set of electronics, the combination can only be guaranteed CE 96 compliance.

5 1. Introduction 5 CPC 125/65 M 1. Introduction The CPC electronics has been designed for driving Channeltron systems in pulse counting mode. It comprises 3 discrete units. Pulse counting pre-amplifier with electronic-to-optical signal conversion Electron multiplier HV power supply unit Receiver with optical-to-electronic (TTL) signal conversion. These units together provide a complete pulse detection facility for use with electron spectrometers. Depending on the ordered configuration the number of channels and/or boards may differ. The receiver provides two output signals: TTL pulses for digital pulse counting equipment and an analogue signal suitable for ratemeter indication. This manual serves as a technical reference only. For details of the setup please refer to the relevant User's Guide. Normal Use The CPC electronics consists of a preamplifier, a high voltage supply and a receiver, to be used in conjunction with Channeltron analysers for electron spectroscopy such as the OMICRON EA 125 hemispherical analyser or AR 65 angle resolved hemispherical analyser. The CPC electronics shall always be used in combination with an EA 125 system consisting of EA 125 analyser U7/1, U7/5 or U7/7 AR 65 analyser, MCD1 or MCD3 EAC or EAC EAC or EAC PC PEN EA (or succeeding models) including EIS software package, SAC and IEEE interface board PC PEN AR (or succeeding models) including EIS software package, SAC and IEEE interface board The CPC Electronics shall always be used with original cable sets which are explicitly specified for this purpose with all cabling connected and secured, if applicable with all electronics equipment switched on in an indoor research laboratory environment by personnel qualified for operating delicate scientific equipment in accordance with all related manuals. Attention: Please read the safety information in all related manuals before using the instrument.

6 2. Safety Information 6 CPC 125/65 M 2. Safety Information Important: Please read this manual and the safety information in all related manuals before installing or using the electronics equipment. The safety notes and regulations given in this and related documentation have to be observed at all times. Check for correct mains voltage before connecting any equipment. Do not cover any ventilation slits/holes so as to avoid overheating. The CPC electronics may only be handled by authorised personnel. Warning: Lethal Voltages!! Adjustments and fault finding measurements may only be carried out by authorised personnel qualified to handle lethal voltages. Lethal voltages are present at or near the connectors of the preamplifier. Extreme caution should be exercised when carrying out any test measurements at this part of the circuit. Lethal voltages are present inside the preamplifier and the high voltage supply units. Always All connectors which were originally supplied with fixing screws must always be used with their fixing screws attached and tightly secured. Always disconnect the mains supplies of all electrically connected units before - opening the vacuum chamber or a control unit case, - touching any cable cores or open connectors. Leave for a few minutes after switching off for any stored energy to discharge.

7 2. Safety Information 7 CPC 125/65 M Never Never have in-vacuum components connected to their electronics in the corona pressure region, i.e. between 10 mbar and 10-3 mbar, so as to avoid damage due to corona discharge. This product is only to be used: indoors, in laboratories meeting the following requirements: altitude up to 2000 m, temperatures between 5 C / 41 F and 40 C / 104 F (specifications guaranteed between 20 C / 68 F and 25 C / 77 F) relative humidity less than 80% for temperatures up to 31 C / 88 F (decreasing linearly to 50% relative humidity at 40 C / 104 F) pollution degree 1 or better (according to IEC 664), overvoltage category II or better (according to IEC 664) mains supply voltage fluctuations not to exceed ±10% of the nominal voltage

8 3. Preamplifier 8 CPC 125/65 M 3. Preamplifier The preamplifier connects to the Channeltron feedthrough of the EA 125 or AR 65 analyser. It receives a high voltage supply and DC power supplies from the multiplier supplies unit. The high voltage Channeltron bias supply (max. 3.6 kv) is ripple filtered and connected to the Channeltron output. Capacitor C1 isolates the high voltage between the multiplier output and sensing amplifier U1. Test point TP2 is used to measure the output pulse from U1 using an oscilloscope. Here the pulse height is in the region of 300 mv to 1.3 V, 25 ns to 30 ns wide. Amplifier U2 is a high speed comparator which detects the pulses which exceed the threshold level set by RV1. The threshold level is usually set in the region of 50 mv and can be measured between TP3 and TP4. channeltron output RV LK LK3 C1 25 ns U1 1.3V U2 70 ns input protection wideband pulse amplifier threshold level control high speed comparator dead time control fibre optic driver LED1 VR1 TP2 TP3 TP7 U8 / U9 U3 pulse stretcher U4 Oscilloscope 5 ms TP9 TP1 TP4 LED2 pulse display indicator Figure 1. Preamplifier schematic circuit diagram. Typical DC level at TP3 is 50 mv; adjust according to system noise. The combination of U8 + U9 produces pulse widths depending on the settings of LK2 and LK3 (default setting: 35 ns pulse width, 70 ns dead time). The output of this is used to trigger a monostable pulse stretcher U4, the optical fibre driver U3, Q1,2,3,4 and the optical fibre LED1. Note that the optical fibre LED is always on. Link 2 Link 3 Pulse Width Dead Time ns 70 ns ns 80 ns ns 130 ns invalid setting invalid setting Table 2. Preamplifier jumper settings, see also figure 1.

9 3. Preamplifier 9 CPC 125/65 M MULTICHANNEL PRE-AMP TP1 (GND) TP2 PREAMP OUTPUT RV1 TRESHOLD ADJUST THRESHOLD ( MONITORING) TP4 TP3 (0V) OPTICAL SIGNAL OUTPUT (top view) LED MONITOR (cover removed)... Figure 2. EA 125 multichannel preamplifier top view and with cover removed, example. Note that the number of channels varies according to the ordered configuration. General Information Operating Principle voltage amplification Linear Gain 100 Signal Input Impedance Protection 100 Ω Si diode + gas arrestor Monitor Output Threshold Monitor discriminator voltage, level adjustable 0 to +800 mv Specifications Pre-Amplifier EA 125 AR 65 weight one channel version 4.5 kg 2.2 kg weight three channel version kg weight five channel version 5.1 kg - weight seven channel version 5.4 kg - dimensions 28 cm 23 cm 11 cm 20 cm 14 cm 9 cm Please note: The multi-channel preamplifier case varies according to the number of channels. Panel Elements

10 3. Preamplifier 10 CPC 125/65 M CEM SUPPLIES DC SUPPLIES pin male socket for Channeltron rear bias supplies. For the pinout please refer to page pin twist lock DIN, female. Power requirements: ±9 V to ±13 V DC unregulated. Pin assignments: pin 1: GND pin 2: + V pin 3: - V pin 4: GND - V + V LEDs indicate normal functioning when lit.

11 4. Multiplier Supplies 11 CPC 125/65 M 4. Multiplier Supplies Figure 3. Multiplier supplies unit. Schematic diagram. Rear Panel FRINGE FIELD SHV connector FRONT BIAS SHV connector FRINGE FIELD ISS SHV connector only fitted in ISS versions, blanked otherwise. FRONT BIAS ISS SHV connector only fitted in ISS versions, blanked otherwise. DC SUPPLIES pin twist lock DIN, female. Power requirements: ±9 V to ±13 V DC unregulated. Pin assignments: pin 1: GND pin 2: + V pin 3: - V pin 4: GND F. B. ADJUST Trimmer potentiometer for Channeltron front bias

12 4. Multiplier Supplies 12 CPC 125/65 M CEM SUPPLIES CEM ON/OFF 15-pin female socket for Channeltron rear bias supplies (high voltage). Pin assignments: pin A: CH1 HV pin B: CH2 HV pin C: CH3 HV pin D: CH4 HV pin E: CH5 HV pin F: CH6 HV pin H: CH7 HV pin P: HV PROTECT pin R: HV PROTECT pin S: SCREENS Please note: HV will not be switched on unless pins P + R are linked. 3-pin MINI DIN for Channeltron ON/OFF control. Attention: upon connecting pins "1" and "2" the multiplier high voltage is on. - V + V LEDs indicate normal functioning when lit. -70V -15V +70V +15V LEDs indicate normal functioning when lit. Fan. MAINS INPUT This unit is supplied with a 3-pin standard European mains socket for AC input of 100, 110, 120, 200, 220, 240 volts ±5% and 50 or 60 Hz, set to customer specification. The wire insulations of the standard 3-lead mains cable are coloured in accordance with the following code: FUSE Brown: Green/Yellow: Blue: Live Earth Neutral Mains fuse(s): use 5 mm, 20 mm long 1 A ("T") for V AC 2 A ("T") for V AC To change the fuse disconnect mains lift the flap using a screw driver for leverage replace the fuse as indicated above re-fit the fuse holder.

13 4. Multiplier Supplies 13 CPC 125/65 M Front Panel OUTPUT ADJUST MULT ON 10-turn potentiometer for Channeltron output adjustment. Range: 250 V to 3.6 kv max. LED warning that multiplier HV is on Top panel H.V. ADJUST Channeltron HV ADJUST: each supply individually adjustable by 20-turn trimmer potentiometers accessible by removing the top panel. Figure 4. Location of the HV adjustment potentiometers. Multiplier HV Supply Specifications Range Stability Dimensions and weight 250 V to 3.6 kv 1%/week, 0.2%/hour 2 U rackmount case. Weight 5.6 kg

14 5. Optical Receiver 14 CPC 125/65 M 5. Optical Receiver The optical receiver detects the low level pulses transmitted by the preamplifier. These are then differentially amplified by U1 to remove noise and to define the pulses. The output U1 is then shaped using a differential line receiver (U2) and inverted by a programmable slew rate driver (U3). The polarity of the pulses transferred to the computer counting board is selected by link LK2. The F/V converter (U5) is connected to produce an analogue output which is proportional to the count rate with a sensitivity of 10 V per 1 Mcps or 10 V per 100 kcps dependent on the setting of link LK1. This voltage is then passed through a filter and ripple rejection stage. The polarity of the output signal is selected by link LK3. LK1 LK2 LK3 Function 1-2 Positive pulse 2-3 Negative pulse 1-2 Ratemeter 100 khz full scale 2-3 Ratemeter 1 MHz full scale 1-2 F-V output FSD-10 V 2-3 F-V output FSD+10 V Table 3. Optical receiver jumper settings, see also figure 5. Connecting a multimeter to the analogue output makes a simple ratemeter. to computer optical detector U1 U2 U3 differential amplifier pulse shaper inverter LK U5 LK1 1 F / V converter 3 2 divide by 10 U4 R LED DISPLAY Note: visible only at high cps. LK3 U6 filter / ripple reduction TP6 analogue output 0 to +/-10 V = 100 khz / 1 MHz Figure 5. Fibre optic receiver. Block diagram of one channel.

15 5. Optical Receiver 15 CPC 125/65 M 0 1 rear panel optical signal inputs front panel LEDs analogue voltage outputs Figure 6. Receiver with 5 channels fitted, schematic diagram. Note that the number of channels varies according to the ordered configuration. Panel Elements pin D-sub connector for 3-channel TTL count output to the computer. Pin assignments: pin 8 counter 1 pin 15 counter 2 pin 7 counter 3 pin 5 counter 4 pin 13 counter 5 pin 6 counter 6 pin 10 counter 7 pin 12 SCREEN -15V +15V +5V LEDs indicate normal functioning when lit Clip socket with internal photo-diode for optical signal input. The related plug contains a fibre optic cable. It should be oriented correctly, i.e. with the press-on clip towards the open part of the socket. LEDs indicate counts present (brightness indicates count rate). 3-pin MINI-DIN socket for analogue voltage output. Pin assignments: pin 1: signal pin 2: (not connected) pin 3: GND

16 5. Optical Receiver 16 CPC 125/65 M MAINS INPUT This unit is supplied with a 3-pin standard European mains socket for AC input of 100/200 or 110/120/220/240 volts ±5% and 50 Hz or 60 Hz, set to customer specification. The wire insulations of the standard 3-lead mains cable are coloured in accordance with the following code: FUSE 0 1 Brown: Green/Yellow: Blue: Live Earth Neutral Mains fuse(s): 5 mm, 20 mm long use 1 A ("T") for V AC 2 A ("T") for V AC To change the fuse disconnect mains lift the flap using a screw driver for leverage replace the fuse as indicated above re-fit the fuse holder. Receiver Specifications Size and weight Range F-V output 280 mm 280 mm 60 mm, 3.4 kg 0 to 14 MHz 0 to ±10 V for 0 to 100 khz / 1 MHz

17 6. Trouble Shooting 17 CPC 125/65 M 6. Trouble Shooting If the system shows a malfunction and you suspect the preamplifier is faulty, follow the procedure below. Warning: Lethal Voltages!! Adjustments and fault finding measurements as well as installation procedures and repair work may only be carried out by authorised personnel qualified to handle lethal voltages. Caution: Never remove the front panel on the preamplifier unit with the multiplier HV switched on. Up to 3.6 kv are present inside the unit. Attention: Please replace any panels or covers after work has been carried out on any electrical unit. General Operational Test of the Preamplifier Switch the Channeltron high voltage off. Switch the mains supply off to the multiplier unit. Remove the front panel on the preamplifier unit. Switch the mains to the multiplier unit on, making sure the red multiplier LED on the front panel of the EAC 300 or the EAC 2000 is not lit. Disconnect the input of the preamplifier from the Channeltron and turn the level trimmer "Discr. Level Adjust" RV1 fully anticlockwise for maximum sensitivity. Attention: never use a bare wire or non-insulated screw driver as there may still be high voltage present due to charged capacitors. Touch the inner contact of the SHV-connector "Channeltron Signal Input" with an insulated screw driver. The ratemeter in the receiver should show a high count rate. Alternatively observe the count indicator LED.

18 6. Trouble Shooting 18 CPC 125/65 M If the preamplifier shows no output signal the supply voltage has to be checked. Are the power indicator LEDs illuminated? If yes, continue with the operational test on the following page. If the power indicator LEDs are not illuminated then open the lid of the box and measure the voltages at test points TP10 (+V) and TP9 (-V) with respect to TP8. The voltmeter should show the following voltages: Test Point Voltages TP8 0 V TP9-9 V to -13 V DC unregulated TP10 +9 V to +13 V DC unregulated If one of these voltages is incorrect or missing, check the voltages at the preamplifier power outlet at the Channeltron power supply unit. The supply voltage for the preamplifier should be ±9 V to ±13 V unregulated. Operational Test (Multiplier and Preamp) Caution: The multiplier high voltage must only be switched on after all electrical connections have been made. Connect an oscilloscope (minimum bandwidth 40 MHz) to the "Signal Monitor" output of the preamplifier (TP2 = signal, TP1 = GND) using a 10:1 probe. The oscilloscope shows pulses with a positive polarity if the system has been set to produce output pulses and the Channeltron works properly. Note that the polarity of the pulses at TP2 is inverted compared to the polarity of the input pulses. If the oscilloscope is set to the correct trigger level the first trigger pulse appears on the screen, followed by an evenly illuminated band because the pulses appear at statistically distributed intervals. Periodical interference caused for example by turbo molecular pumps can be clearly made out as brighter regions in this band. The output pulses have a pulse width of 10 ns to 25 ns and an amplitude about 200 mv to 1.3 V at "Signal Monitor", depending on the Channeltron type and voltage. If you still suspect a fault within the preamplifier or detection system please contact the OMICRON service department, preferably using the FAX form provided on page 20

19 Service at Omicron Should your equipment require service Please contact Omicron headquarters or your local Omicron representative to discuss the problem. An up-to-date address list is available on our website under or via reply service under Make sure all necessary information is supplied. Always note the serial number(s) of your instrument and related equipment (e.g. head, electronics, preamp ) or have it at hand when calling. If you have to send any equipment back to Omicron Please contact Omicron headquarters before shipping any equipment. Place the instrument in a polythene bag. Reuse the original packaging and transport locks. Take out a transport insurance policy. For ALL vacuum equipment: Include a filled-in and signed copy of the "Declaration of Decontamination" form which can be found at the back of the equipment manual. No repair of vacuum equipment without a legally binding signed deconta tami mination declaration! Wear suitable cotton or polythene gloves when handling the equipment. Re-insert all transport locks (if ( applicable). Cover the instrument with aluminium foil and/or place it in a polythene bag. Make sure no dust or packaging materials can contaminate the instrument Make sure the plastic transport cylinder (if ( applicable) is clean. Fix the instrument to its plastic cylinder (if applicable). Omicron NanoTechnology GmbH February 2002

20 Service FAX Reply To OMICRON NanoTechnology GmbH Test and Service Department Limburger Straße Taunusstein Germany Tel: FAX: From Tel:... FAX:... Type of Instrument... Serial Number... Purchasing Date... (Last Service Date... ) Problem: Date: Signature: Omicron NanoTechnology GmbH February 2002

21 Useful OMICRON Contacts An up-to-date address list is available on our website under or via reply service under Omicron NanoTechnology GmbH February 2002

22 Index 22 CPC 125/65 M Index A adjustments...6; 17 analyser, hemispherical...5 application, field of...5 C CE compliance, conditions of...4 Channeltron...18 circuit diagram optical receiver pre-amp... 8 copyright...2 D dead time jumper settings...8 E EAC EAC F fault finding...6; 17 fuses...12; 16 H hemispherical analyser...5 J jumper settings optical receiver pre-amp... 8 L lethal voltages...6; 17 limitations...7 M malfunction...17 measurements, fault finding...6; 17 multiplier supplies...11 N normal use...5 O optical receiver...14 oscilloscope...18 P power connector...10; 11 preamplifier...8 preamplifier schematic diagram...8 pulse counting...5 R ratemeter...14 receiver jumper settings...14 receiver, optical...14 S safety information...6; 17; 18 service procedure...19 specifications multiplier supplies optical receiver pre-amp... 9 T trouble shooting...17 V voltage, lethal...6; 17