Model 480 Pulser Operating and Service Manual
Contents
1. 2 2 2 GONTROLS E E 2 223 OURS rara TPs Mek T A A N 2 2 4 ELECTRICAL AND MECHANICAL 2 S J INSTALLATION e n a E E E E toes 2 3 GENERAL reei e a a A A T uli ul bali lalla tal ah lal hus ae 2 3 2 2 22 2 4 OPERATION E ee RRA ea ee 3 410 PANEL CONTROLS ein Wie ite ets Se ee er i es ea ee 3 4 2 INITIAL TESTING AND OBSERVATION OF PULSE WAVEFORMS 3 4 3 CONNECTOR DATA 4 407 2 3 4 4 TYPICAL OPERATING CONSIDERATIONS 4 5 MAINTENANCE 7 5 1 TESTING PERFORMANCE OF THE PULSER 7 5 2 ADJUSTMENT OF DECAY TIME OF OUTPUT PULSE 8 5 3 TABULATED TEST POINT VOLTAGES 4 8 5 4 SUGGESTIONS FOR 9 SAFETY INSTRUCTIONS AND SYMBOLS This manual contains up to three levels of safety instructions that must be observed in order to avoid personal injury and or damage to equipment or other property These are DANGER In2. less than 10 nsec the pulse fall time to one half of its maximum amplitude should be between 110 and 150 Usec 8 Adjust the Pulse Height dial for a Pulse of 800 mV at the attenuated output test point As the Attenuator switches are switched in the output pulse should be between the following limits OUTPUT PULSE Setting X2 X5 X10 X10 Original 800 800 800 800 Lower 360 144 72 72 Upper 440 176 88 88 rt 9 Set the Polarity switch to Neg There should be no change in amplitude from the Pos position Observe the output with a sweep of 5 msec cm and look for skipping or other erratic behavior of the relay 5 2 ADJUSTMENT OF DECAY TIME OF OUTPUT PULSE As the 480 is normally supplied the decay time of the output pulse is essentially fixed The output Pulse will decay with the time constant of 400 Usec if the Attenuated output only is terminated in 100Q and will decay with a time constant of approximately 200 usec if both the Direct and Atten Outputs are terminated In the event that a time constant shorter than 200 usec is desired it is necessary to parallel a fixed resistor from the normally open contact of the mercury wetted relay to ground The value of this shunting resistor will depend upon the exponential time constant desired The addition of this resistor should physically be in close proximity to the actual relay that is to say the resistor should be added directly onto the etched circuit board Decay time c
3. US DOE Report TID 20893 Rev An ORTEC 4001 4002 Series Bin and Power Supply provides all necessary power through the rear module power connector The ORTEC 400 Series is designed so that it is not possible to overload the Bin Power Supply with a full complement of modules in the Bin However this may not be true when the Bin contains modules of other than ORTEC design All signal levels and impedances are compatible with other modules in the ORTEC 400 Series 1 2 BASIC FUNCTION The 480 provides output pulses that are characterized by a fast rise time and a slow exponential decay time These pulses are generated by charging a capacitor to an internal reference voltage through a mercury relay and then discharging the capacitor through the switching action of the mercury relay into a fixed resistive load The use of mercury wetted relay contacts provides a very fast rise time typically less than 5 nsec 10 90 rise time with an absolute minimum of contact bounce or other perturbations of the waveform for the first few microseconds The output impedance of the pulse generator on both the direct and attenuated output is 100Q The direct output provides a trigger pulse that allows the stable synchronization of an oscilloscope or other timing equipment from a signal which does not vary in amplitude as the attenuators are switched in and out The attenuated output has a series of pi attenuators between the mercury wetted relay contacts and
4. applied to reduce the effective detector capacity shunting the charge sensitive preamplifier input Also with the charge terminator used simultaneously with a semiconductor detector it must be remembered that the charge terminator effectively shunts the detector with approximately 2 5 pF of shunt capacity which will correspondingly degrade the signal to noise performance of the preamplifier For voltage drive to an instrument under test use coaxial cable having an impedance of approximately 100Q RG 62 U between the pulse generator and the instrument under test Place a 100Q termination at the instrument end of the cable in shunt with the input of the instrument Calibrating the Test Pulser and Amplifier for Energy Measurements The 480 may easily be calibrated so that the maximum Pulse Height dial reading 1000 divisions is equivalent to a specific MeV loss in a radiation detector The procedure is as follows 1 Connect the detector to be used to the spectrometer system i e preamplifier main amplifier and biased amplifier 2 Allow particles from a source of known energy alpha particles for example to fall on the detector 3 Adjust the amplifier gains and the bias level of the biased amplifier to give a suitable output pulse 4 Set the pulser Pulse Height potentiometer at the energy of the alpha particles striking the detector e g for a 5 1 MeV alpha particle set the dial at 510 divisions 5 Turn on the pul
5. if perfect amplifier linearity is assumed As an example of this method assume that the amplifier under test has essentially zero output impedance Set R1 equal to 1000 and R2 equal to 2000 Let diodes D1 and D2 be 2N2048 connected as diodes Only one half of the actual amplifier output voltage can be measured directly at point A due to the superposition of the outputs of the Pulse generator via R1 and the amplifier via R2 To specify nonlinearity as a percentage of full Output voltage the calibration of 10 mV cm will be equal to 10 mV 5 V or 0 2 per cm Therefore it is seen that 0 1 is quite easily resolved In addition to linearity measurements it is obvious that this method can be quite useful in measurements of temperature stability Pulse Height Analyzer Calibration With the Pulser calibrated to read directly in terms of energy as described earlier in this section the calibration of a complete spectrometry system from preamplifier to multichannel analyzer i e analog to digital converter ADC can readily be accomplished by simply feeding into the preamplifier a calibrated energy signal and observing the corresponding channel into which it is assigned by the ADC An important consideration in this test involves ensuring that the linear system goes through zero and that the output of the pulse generator is properly terminated The attenuator switches in the 480 have an accuracy controlled by 1 metal film resistors and co
6. it The use of these switches therefore alters the pulse amplitude appearing at the attenuated output for a given setting of the Pulse Height control The attenuated output should always be terminated with 100Q The polarity of the output pulse will be determined by the Neg Pos switch TPI An oscilloscope test point is on the front panel for monitoring the signal on the Direct Output BNC connector CN1 This test point has a 470Q series resistor connecting it to CN1 TP2 An oscilloscope test point is also on the front panel for monitoring the signal on Attenuated Output BNC connector CN2 This test point has a 470Q series resistor connecting it to CN2 4 4 TYPICAL OPERATING CONSIDERATIONS Charge and Voltage Terminators A charge terminator that consists of a 100Q shunt resistor with a 2 pF series capacitor is supplied for use with ORTEC charge sensitive preamplifiers When this terminator is used the maximum output pulse is 5 V on 10 pC 220 MeV for silicon diode detectors When the charge terminator is used to drive a charge sensitive preamplifier a coaxial cable having an impedance of approximately 100Q RG 62 U should be used between the pulse generator and the charge terminator The terminator should be located at the input connector of the preamplifier The charge terminator may be used with or without a detector being applied to the input of a preamplifier If a detector is connected to the preamplifier detector bias must be
7. of quality control tests designed to expose any flaws in materials or workmanship Permanent records of these tests are maintained for use in warranty repair and as a source of statistical information for design improvements Repair Service If it becomes necessary to return this instrument for repair it is essential that Customer Services be contacted in advance of its return so that a Return Authorization Number can be assigned to the unit Also ORTEC must be informed either in writing by telephone 865 482 4411 or by facsimile transmission 865 483 2133 of the nature of the fault of the instrument being returned and of the model serial and revision on rear panel numbers Failure to do so may cause unnecessary delays in getting the unit repaired The ORTEC standard procedure requires that instruments returned for repair pass the same quality control tests that are used for new production instruments Instruments that are returned should be packed so that they will withstand normal transit handling and must be shipped PREPAID via Air Parcel Post or United Parcel Service to the designated ORTEC repair center The address label and the package should include the Return Authorization Number assigned Instruments being returned that are damaged in transit due to inadequate packing will be repaired at the sender s expense and it will be the sender s responsibility to make claim with the shipper Instruments not in warranty should follow
8. MS Noise V Bias Voltage Fig 4 4 Amplifier and Detector Noise vs Bias Voltage PULSE ENERATOR ATTENUATED 20015 AMPLIFIER ZolP R Zo A 2000 T i ee VERTICAL Fig 4 5 Measuring Linearity by the Null Balance Method 3 Then obtain the amplifier noise resolution spread by measuring the FWHM of the pulser spectrum The detector noise resolution spread for a given detector bias can be determined in the same manner by connecting a detector to the preamplifier input The amplifier noise resolution spread of course must be subtracted The detector noise will vary with detector size and bias conditions as indicated in Fig 4 4 and possibly with ambient conditions Amplifier Linearity Measurements The measurement of amplifier linearity can be quickly and simply done by utilizing the method outlined in Fig 4 5 The method consists of bucking out two voltage signals from low impedance sources and measuring the amplitude differential at a null point The following conditions of Fig 4 5 should be considered when linearity measurements are made The output impedance of the Direct Output must be 1000 The amplifier must be set in the inverting mode of operation i e for the negative input shown the amplifier must produce a positive Output Pulse The impedance seen from point A to ac or signal ground via point C should be equal to the impedance seen from p
9. Model 480 Pulser Operating and Service Manual Printed in U S A ORTEC Part No 733390 1202 Manual Revision B Advanced Measurement Technology Inc a k a ORTEC a subsidiary of AMETEK Inc WARRANTY ORTEC warrants that the items will be delivered free from defects in material or workmanship ORTEC makes no other warranties express or implied and specifically NO WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE ORTEC s exclusive liability is limited to repairing or replacing at ORTEC s option items found by ORTEC to be defective in workmanship or materials within one year from the date of delivery ORTEC s liability on any claim of any kind including negligence loss or damages arising out of connected with or from the performance or breach thereof or from the manufacture sale delivery resale repair or use of any item or services covered by this agreement or purchase order shall in no case exceed the price allocable to the item or service furnished or any part thereof that gives rise to the claim In the event ORTEC fails to manufacture or deliver items called for in this agreement or purchase order ORTEC s exclusive liability and buyer s exclusive remedy shall be release of the buyer from the obligation to pay the purchase price In no event shall ORTEC be liable for special or consequential damages Quality Control Before being approved for shipment each ORTEC instrument must pass a stringent set
10. dicates a hazard that could result in death or serious bodily harm if the safety instruction is not observed WARNING Indicates a hazard that could result in bodily harm if the safety instruction is not observed CAUTION Indicates a hazard that could result in property damage if the safety instruction is not observed Please read all safety instructions carefully and make sure you understand them fully before attempting to use this product In addition the following symbol may appear on the product ATTENTION Refer to Manual DANGER High Voltage Please read all safety instructions carefully and make sure you understand them fully before attempting to use this product SAFETY WARNINGS AND CLEANING INSTRUCTIONS DANGER Opening the cover of this instrument is likely to expose dangerous voltages Disconnect the instrument from all voltage sources while it is being opened WARNING Using this instrument in a manner not specified by the manufacturer may impair the protection provided by the instrument Cleaning Instructions To clean the instrument exterior Unplug the instrument from the ac power supply Remove loose dust on the outside of the instrument with a lint free cloth Remove remaining dirt with a lint free cloth dampened in a general purpose detergent and water solution Do not use abrasive cleaners CAUTION To prevent moisture inside of the instrument during external cleaning use only enough li
11. es have an accuracy controlled by 1 metal film resistors and depend upon the attenuated output being terminated in 100Q Off On This front panel slide switch allows the internal relay to be driven from the ac line The frequency of the ac line will be 50 to 60 Hz Neg Pos The Polarity of the output signal will be either negative or Positive as determined by the setting of this front panel slide switch 4 2 INITIAL TESTING AND OBSERVATION OF PULSE WAVEFORMS See Section 6 1 for test performance data 4 3 CONNECTOR DATA CN 1 The Direct Output BNC connector provides a dc coupled output that looks back directly at the relay and has an output impedance of 100Q The output of this connector provides a constant output voltage for a given setting of the Pulse Height control independent of the position of the Attenuator switches Output voltage range is from 0 to 5 V maximum into 100Q and 0 to 10 V into a high impedance The direct output may or may not be terminated with 1000 terminator If the direct output is terminated with a 100Q terminator the decay time of the output pulse will change from a nominal value of 400 usec to a value of 200 usec The polarity of the Direct Output pulse will be either negative or positive as determined by the Neg Pos switch CN 2 The Attenuated Output BNC connector provides a dc coupled output connector with an output impedance of 100Q The attenuated output has the Attenuators in series with
12. ield cover can be completely removed from the module to enable oscilloscope and voltmeter observations with a minimum chance of accidentally short circuiting portions of the etched board The 480 may be returned to ORTEC for repair service at nominal cost Our standard procedure requires that each repaired instrument receive the same extensive quality control tests that a new instrument receives Contact our Customer Service Department 865 483 2231 for shipping instructions before returning an instrument 10 Bin Module Connector Pin Assignments For Standard Nuclear Instrument Modules per DOE ER 0457T Pin Function 1 3 V 2 3V 3 Spare bus 4 Reserved bus 5 Coaxial 6 Coaxial 7 Coaxial 8 200Vdc 9 Spare 10 6V 11 6V 12 Reserved bus 13 Spare 14 Spare 15 Reserved 16 12V 17 12V 18 Spare bus 19 Reserved bus 20 Spare 21 Spare 22 Reserved 41 Function Reserved Reserved Reserved Spare Spare 24 V 24V Spare bus Spare Spare 117 V ac hot Power return ground Reset Scaler Gate Reset Auxiliary Coaxial Coaxial Coaxial 117 V ac neutral High quality ground Ground guide pin Pins marked are installed and wired in ORTEC s 4001A and 4001C Modular System Bins
13. l resolution spread versus external input capacitance in the RC mode is shown in Fig 4 2 Amplifier Noise and Resolution Measurements Using a Pulse Height Analyzer Probably the most convenient method of making resolution measurements is with a pulse height analyzer as shown by the setup illustrated in Fig 4 3 The amplifier noise resolution spread can be measured correctly with a pulse height analyzer and the 480 as follows Resolution FWHM 20 1 Select the energy of interest with the 480 and set the linear amplifier and biased amplifier gain and bias level controls so that the energy is ina convenient channel of the analyzer 2 Calibrate the analyzer in keV per channel using the purser Full scale on the pulser dial is 10 MeV when calibrated as described in Calibrating the Test Pulser and Amplifier for Energy Measurements PERCENT RELATIVE AMPLITUDE 20016R 40 60 100 200 400 600 1000 Input Capacitance pF Fig 4 2 Resolution Spread vs External Input Capacity ORTEC ORTEC ORTEC LINEAR AMPLIFIER BIASED AMPLIFIER PREAMP DETECTOR CAPACITOR ORTEC PULSER ORTEC MULTICHANNEL PULSE HEIGHT ANALYZER PULSE STRETCHER 500023 Fig 4 3 Measuring Resolution with a Pulse Height Analyzer A ORTEC BA 030 007 300 B ORTEC 025 050 100 C ORTEC BA 025 100 100 D ORTEC BA 030 200 100 E ORTEC BA 045 450 100 R
14. oint A to ac or signal ground via point B The diodes D should be germanium units with high g The diodes can be replaced with high frequency germanium transistors with the base connected to the collector so that the emitter base functions as the diode Transistors suitable for this test include 2N779 2N964 2N976 2N2048 The diodes serve as bipolar voltage clamps to limit the voltage swing at point A to the forward voltage drop across the diodes The diode resistor network should be constructed so as to minimize the stray capacitance around this network The network should be physically located on the oscilloscope input connector for the same reason Initially the output of the Pulser and amplifier should be set for 10 V This should be measured with cars and consideration should be given for the output impedance of both the Pulser and amplifier By observing the waveshape at point A Fig 4 5 the fine gain of the amplifier and the attenuation controls should be adjusted until a null is obtained between time and t At null the sensitivity of the oscilloscope should be set to 10 mV cm for best resolution of the null measurement The actual measurement of linearity is accomplished by dialing the Pulse Height dial to 0 resulting in the amplifier output being reduced to zero Since the Pulser supplies signals in parallel both to the bridge for null and to the amplifier varying the Pulser output will have no effect on the null
15. on the 402 The performance test consists of the following 1 Set the front panel controls on the 480 as follows a relay switch to On b polarity switch to Pos c Cal set to full clockwise and Pulse Height control to 1000 d all Attenuator switches set to X1 position e Direct Output terminated in 100Q and kept terminated in 100Q throughout the test 2 Apply power to the Bin and listen for running of the mercury relay which will be characterized by a low frequency hum 50 or 60 Hz 3 Set the relay switch to Off Measure the dc voltage from the wiper of the Pulse Height switch on the rear panel to ground It should be greater than 9 V 4 Dial the Cal control fully counterclockwise and again measure the dc voltage from the wiper of the Pulse Height switch to ground It should be less than 4 V Turn the Cal control clockwise until the voltage is 10 V 5 Set the relay switch to On 6 Measure the pulse at the direct output test point 1 pulse amplitude should be between the limits of 4 0 and 6 0 V The pulse rise time 10 90 should be less than 10 nsec the pulse fall time to one half of its maximum amplitude should be between 230 and 290 usec Do not remove the 100 terminator from the Direct Output 7 Terminate attenuated output with 100Q Measure the pulse at the attenuated Output test point The pulse amplitude should be between the limits of 4 0 and 6 0 V The pulse rise time 10 90 should be
16. onstants as short as 10 usec can be accomplished quite easily 5 3 TABULATED TEST POINT VOLTAGES The following voltages are intended to indicate the typical dc voltages measured on the etched circuit board In some cases the circuit will perform satisfactorily even though due to component variations there may be some voltages that measure outside the given limits Therefore the voltages given should not be taken as absolute values but rather are intended to serve as an aid in troubleshooting All voltages are measured from ground with dvm having input impedance of 10 MQ or greater Polarity switch set to Neg Transistor No and Element Qic 02 Lower voltage limit 6 4 12 8 Upper voltage limit 7 4 14 8 5 4 SUGGESTIONS FOR TROUBLESHOOTING In situations where the 480 is suspected of malfunction it is essential to verify such malfunction in terms of simple pulse generator impulses at the output In consideration of this the 480 must be disconnected from its position in any system and routine diagnostic analysis performed on the Pulser with a vacuum tube voltmeter and oscilloscope It is imperative that testing not be performed with any amplifier system until the Pulser performs satisfactorily by itself The testing instructions of Section 6 1 of this manual and the circuit description in Section 5 are intended to provide assistance in locating the region of trouble and repairing the malfunction The guide plate and sh
17. quid to dampen the cloth or applicator Allow the instrument dry completely before reconnecting it to the power source vi ORTEC MODEL 480 PULSER 1 DESCRIPTION 1 1 GENERAL The ORTEC 480 is a modular pulse generator designed to simulate the detection of a nuclear particle reaction in a solid state or scintillation detector The unit features good stability as a function of temperature and time 1 overall accuracy and a front panel Cal control which enables it to be calibrated to read directly in terms of equivalent energy deposited in a detector The pulses are generated with a mercury relay switch whose frequency is the frequency of the ac line The instrument has an internal stable reference voltage that is effectively independent of the modular power supply and ac line voltage changes The unit has four attenuator toggle switches for a maximum attenuation of 1000 1 The direct output precedes the attenuator switch and provides a means of stable oscilloscope triggering Two terminators are provided with the 480 a charge terminator and 1000 voltage terminator The use of a charge terminator allows the voltage output pulse of the 480 to be converted to a charge pulse for subsequent amplification by a charge sensitive preamplifier A holder is provided on the rear panel to store the charge terminator when it is not in use This instrument is designed to meet the recommended interchangeability standards of
18. ser use the Cal potentiometer and the Attenuator switches to set the output due to the pulser to the same pulse height and shape as the pulse obtained in step 3 Amplifier Noise and Resolution Measurements As shown Fig 4 1 a preamplifier amplifier pulse generator oscilloscope and wide band rms voltmeter such as the Hewlett Packard 400D are required for this measurement Connect a suitable capacitor to the input to simulate the detector capacitance desired To obtain the resolution spread due to noise 1 Measure the rms noise voltage Ems at the linear amplifier output ORTEC PREAMP DETECTOR OR ki ORTEC PULSER 20002 Fig 4 1 Measuring Amplifier and Detector Noise Resolution ORTEC OSCILLO SCOPE LINEAR AMPLIFIER RMS VOLTMETER 2 Turn on the 480 and adjust the linear amplifier output to any convenient readable voltage E as determined by the oscilloscope The full width at half maximum FWHM resolution spread due to the amplifier noise is then N FWHM 2 66 Ems Egia E where Ega is the pulser dial reading in MeV and the factor 2 66 is the correction factor for rms to full width at half maximum 2 35 and noise to rms meter correction 1 13 for average indicating voltmeters such as the Hewlett Packard 400D The resolution spread will depend upon the total input capacity since the capacitance degrades the signal to noise ratio much faster than the noise A typica
19. the output BNC connector This allows the attenuation of the signal by a fixed amount depending upon the particular switch operated in the series attenuator The primary purpose of the pulse generator is to simulate radiation detection signals Since the pulses are generated from an electromechanical device the mercury wetted relay the frequency of the pulse generator is correspondingly rather slow i e the frequency of the ac line 2 SPECIFICATIONS 2 1 PERFORMANCE Temperature Stability 0 01 C 0 to 50 C Line Voltage Stability 0 005 per 10 change in line voltage Ripple and Noise 0 003 of pulse amplitude Nonlinearity 0 25 of full scale Rise Time Exponential waveform lt 10 nsec 10 to 90 Fall Time Exponential decay with 200 or 400 usec time constant depending on whether or not the direct output is terminated 2 2 CONTROLS Cal 22 turn potentiometer on front panel covers gt 2 1 amplitude span for normalization of Pulse Height control to read directly in equivalent energy Pulse Height Front panel potentiometer controls output pulse height from zero volts to the maximum determined by the Attenuator switches the Cal control setting and the termination load Attenuator Front panel switches provide step attenuation over 1000 1 range with 1 resistors X2 X5 X10 X10 Off On Front panel slide switch allows internal relay to be driven from the ac line Front panel slide s
20. the same procedure and ORTEC will provide a quotation Damage in Transit Shipments should be examined immediately upon receipt for evidence of external or concealed damage The carrier making delivery should be notified immediately of any such damage since the carrier is normally liable for damage in shipment Packing materials waybills and other such documentation should be preserved in order to establish claims After such notification to the carrier please notify ORTEC of the circumstances so that assistance can be provided in making damage claims and in providing replacement equipment if necessary Copyright 2002 Advanced Measurement Technology Inc All rights reserved is a registered trademark of Advanced Measurement Technology Inc All other trademarks used herein are the property of their respective owners CONTENTS WARRANT Y ahaha apa a a ea Re alae ii SAFETY INSTRUCTIONS AND SYMBOLS iv SAFETY WARNINGS AND CLEANING INSTRUCTIONS 2 1 DESCRIPTION sates nck ehh ee ee ee ee a eae 1 e GENERAL i ath 1 1 2 BASIS FUNG TION sa ete ei tets octet aa TO noes 1 2 SPECIFICATIONS ele aig elgg g ele tig ei 2 2H REREFORMANGE 25656 tte ea
21. uld be used to digitally check the linearity of the spectrometer In addition to the attenuator accuracy the Pulse Height control has independent integral nonlinearity of 0 25 This control therefore allows an integral linearity curve of the ADC to be taken over the continuous range of the ADC i e from zero to the maximum address of the ADC Due to the better integral linearity control continuous scanning with the Pulse Height control is the recommended method of checking for system linearity The linearity of the ADC can therefore be determined by having previously taken the linearity curve of the amplifier and preamplifier as outlined earlier in this section 5 MAINTENANCE 5 1 TESTING PERFORMANCE OF THE PULSER The following information is intended as an aid in the installation and checkout of the 480 These instructions present information on front panel controls waveforms at test points and output connectors The following or equivalent test equipment is needed Tektronix Model 580 Series Oscilloscope 1000 BNC Terminators Vacuum Tube Voltmeter Before testing the performance of the 480 take the following preliminary steps 1 Visually check the module for possible damage due to shipment 2 Connect ac power to NIM standard Bin and Power Supply ORTEC 401 402 3 Plug module into Bin and check for proper mechanical alignment 4 Switch ac power on and check the dc Power Supply voltages at the test points
22. urn off the Bin Power Supply when inserting or removing modules The 4001 4002 has test Points on the Power Supply control Panel to monitor the dc voltages When using the 480 outside the 4001 4002 ensure that the power jumper cable used properly accounts for the Power Supply grounding circuits provided the recommended standards of US DOE TID 20893 Rev Both high quality and power return ground connections are provided to ensure proper reference voltage feedback into the Power Supply and these must be preserved remote installations Care must also be exercised to avoid ground loops when the module is operated outside the Bin If the 480 should be inserted in a bin that has no ac voltage distribution the unit will not operate since the relay is driven from the ac line on pins 33 and 41 4 OPERATION 4 1 PANEL CONTROLS Cal A 22 turn potentiometer on the front panel varies the output pulse height continuously over a 2 51 range approximately to allow for normalization of the Pulse Height dial setting Pulse Height The Pulse Height potentiometer on the front panel controls is the output pulse height from zero volts to the maximum determined by the Attenuator toggle switches and the termination load This 10 turn potentiometer has calibration linearity of 0 25 Attenuators Four toggle switches on the front panel control pi attenuators in the attenuated output line the maximum attenuation is 1000 1 These switch
23. witch determines polarity of the output signal 2 3 OUTPUTS Atten Front panel BNC connector provides positive or negative dc coupled output with an impedance of 100Q Direct Front panel BNC connector provides positive or negative dc coupled 0 to 10 V pulse into a high impedance and 0 to 5 V max pulse into 100Q This is equivalent to a range of 0 to 220 MeV energy referred to a silicon detector when used with associated charge terminator Accessories Included One 1000 voltage terminator and one charge terminator 2 4 ELECTRICAL AND MECHANICAL Power Required 24 V 60 mA 12 V 0 mA 24 V 60 mA 12 V 0 mA 115 V ac 8 mA used only to drive relay Weight Shipping 4 1 Ib 1 86 kg Weight Net 2 1 Ib 0 95 kg Dimensions NIM standard single width module 1 25 by 8 714 in Per TID 20893 Rev 3 INSTALLATION 3 1 GENERAL The 480 contains no internal power supply but is used in conjunction with an ORTEC 4001 4002 Series Bin and Power Supply which is intended for rack mounting Therefore if vacuum tube equipment is operated in the same rack with the 480 there must be sufficient cooling air circulating to prevent any localized heating of the 480 and the associated Bin and Power Supply The temperature of equipment mounted in racks can easily exceed 120 F 50 C unless precautions are taken The 480 should not be subjected to temperatures in excess of 120 F 3 2 CONNECTION TO POWER Always t
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