ORTEC Model 583B User Manual 931002 Rev. C
Contents
1. 2 SPECIRIGATIONS br qm MD debes edd put ded e dr CE QUA Red ing 23 PERFORMANCE cnet ed aderat dendi dette a 2 2 CONTROLS 4 iie iex ipe ee ek Dane oe de re ger yon ele obe quede enc Rer ala dante 2 3 INIT ud ar io d em dtp Idi er qoem ur dip 2 4 OUTPUTS Sor Re RR RR UI ee p LE Fate 2 5 ELECTRICAL AND MECHANICAL 1 4 3i INSTAEDEATION s rie tuit t edu ete s Seated donas i Shae gati d aeta dats 33 GENERAL ep e ML Sn Ep CER Ce UA Net ARE Bp RR S LE 3 2 POWER CONNECTION a gaa sie ears her abe eg 3 3 INPUT ret ehe RR me E CR CREE 3 4 OUTPUT CONNECTIONS 4 4 1 3 5 CF DELAY GABLE 52 45 tis whi aetna bie Gee hee as 4 OPERATION ys ettet ese Ed bt ep ob LLL e sae ute 4 1 DIFFERENTIAL MODE a e beg Fh pa E be Fiber beue dde deed pan al vob x er 4 2 INTEGRAEB MOBE ui eee IDEE A eS eee vs 4 3 SLOW RISE TIME REJECT MODE 1 5 TYPICAL APPLICATIONS oc cece regem2. OY eee eee es ve p rq 54 GENEBALE uh ARP USELESS EAR Rd RUND elec diced dr bie FAST SYSTEM Lus ERE EOM Le C Rex 5 3 FAST SEOW SYSTEM e eet e EO ee ecce ee OUR teen e e HR eg 6 REFERENCES une pue ee ure Ur RURAL Pack p IRIS S TR y POR ee RISE IET Galata 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 Indicates 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 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
3. To clean the instrument exterior Unplug the unit from the ac power supply e Remove loose dust on the outside of the instrument with a lint free cloth e 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 liquid to dampen the cloth or applicator e Allow the instrument to dry completely before reconnecting it to the power source vi 583B CF DIFF DISC UPS LEVEL LOWER LEVEL DIFF INT SRT DELAY INPUT OI we WALK WIDTH 9 9 CF OUT s f N IK TIMING OUTPUTS ORTEC MODEL 583B CONSTANT FRACTION DIFFERENTIAL DISCRIMINATOR 1 DESCRIPTION The ORTEC Model 583B Constant Fraction Differential Discriminator Single Channel Analyzer is a single width NIM module that generates accurate timing output signals for a variety of applications It accepts input pulses in the range of 0 to 10 V and generates NIM fast negative outputs and a slow positive output that are based on the Constant Fraction time derivation The 583B can be operated as an integral discriminator or as a single channel analyzer SCA for the anode signals from fast photomultiplier tubes It provides excellent timing characteristics for a wide dynamic range of input signal amplitudes The input impedance of the 583B is 50 O
4. 4 3 SLOW RISE TIME REJECT MODE An SRT timing mode can be used to ensure that leading edge time walk is not introduced by either the LL or UL discriminator Leading edge timing can occur for input signals with exceptionally long risetimes and for amplitude and rise time compensated ARC timing with input signals that exceed the threshold of interest by only a slight amount In SRT mode an input signal that does notcross the LL threshold before the CF zero crossing time will not produce a timing output pulse In differential mode an input signal that does not cross the UL threshold before the zero crossing time will not be inhibited by the UL discriminator from producing an output pulse i i 7 CEE JANAR Cert ELCHE HEN E UE IBS USUS mV div 2 ns div b 1114 Ric ELT A 1 0 5 ns div Fig 1 a RCA 8850 PMT Anode Signal with a 1 in x 1 in KL236 Scintillator and Source b Constant Fraction Zero Crossing Monitor Signal Triggered by the Discriminator Output for the Anode Signal Shown Above c Expanded View of the Constant Fraction Zero Crossing Monitor Signal 5 TYPICAL APPLICATIONS 5 1 GENERAL The 583B can be used in a variety of applications in which precise timing information and energy selection capability are needed Both criteria can be determined for input pulses from PMTs and scintillators However the use of the 58
5. The 583B also has a connector and width adjustment potentiometer for generating and controlling a blocking one shot pulse This blocking one shot is initiated simultaneously with the timing output signals and prevents the unit from generating additional timing output signals during the selected blocking period 1 2 CONSTANT FRACTION PRINCIPLE In the Constant Fraction technique an input signal to the constant fraction CF circuitry is delayed and a fraction of the undelayed pulse is subtracted from it A bipolar signal is generated and its zero crossing is detected and used to produce an output logic pulse The CF shaping delay is controlled by the length of cable externally connected between the two DELAY connectors on the front panel This shaping delay should be optimized for each specific application Optimization requires prior knowledge of the rise time and nominal width of the input signals to the 583B 1 3 INPUT OUTPUT CHARACTERISTICS The 583B accepts negative input signals up to 10 V without saturation The primary usage of the 583B is expected to be with the anode signals from photomultiplier tubes However for integral mode applications other sources of negative signals such as timing filter amplifiers may also be used If an input signal satisfies the logic conditions established with the 583B four output pulses are simultaneously initiated e Two timing output signals from the front panel TIMING OUTPUTS connect
6. external 50 O cable must be provided for the constant fraction shaping delay SRT slow rise time reject Inhibits output signals that would be produced by leading edge timing from the LL and UL discriminators An input signal that does not cross the LL threshold before the constant fraction zero crossing time does not produce an output pulse In DIFF mode an input signal that does not cross the UL threshold before the constant fraction zero crossing time will not be inhibited by the UL discriminator from producing an output pulse DELAY pair of front panel BNC connectors that accept 50 O coaxial cable to set the required constant fraction shaping delay total delay is 0 7 ns plus the delay of the external cable WALK ADJUST Front panel 20 turn screwdriver adjustment for setting the walk compensation for each application WALK MONITOR Front panel test point adjacent to the walk adjust potentiometer permits monitoring the actual dc voltage that is set for the zero crossing reference normally set in the range of 0 5 mV to 2 mV CFMONITOR Front panel BNC connector that allows observation of the constant fraction bipolar timing signal 50 O cable and 50 O terminator required WIDTH ADJUST Front panel 20 turn screwdriver adjustment for setting the width of the pulse at the blocking output variable from 15 to 1000 ns 2 3 INPUT Front panel BNC connector accepts negative input signals from 0 to 10 V with
7. pulse width 10 ns or pulse width at the arming threshold 40 ns for input pulse width gt 10 ns 2 2 CONTROLS UPPER LEVEL Front panel 5 turn precision locking potentiometer used to determine the upper level UL discriminator threshold setting LOWER LEVEL Front panel 5 turn precision locking potentiometer used to determine the lower level LL discriminator threshold setting Also automatically adjusts the threshold level forthe constant fraction pick off arming discriminator Adjustable internally from 0 5 to 1 0 times the LL threshold factory set to 0 5 DISCRIMINATOR MODE Froni panel 2 position locking toggle switch selects one of two modes e DIFF differential Functions as an SCA The LL and UL thresholds are each independently adjustable from 30 mV to 5 V To produce an output pulse the input signal must cross the LL threshold but must not cross the UL threshold within approximately 10 ns after the constant fraction zero crossing time INT integral Functions as an integral discrimi nator The LL threshold sets the minimum input signal amplitude required to produce an output pulse The UL discriminator is not used to determine the timing response from the instrument TIMING MODE Front panel 2 position locking toggle switch selects one of two modes CF constantfraction Theinstrumentoperates in the constant fraction timing mode The constant fraction attenuation factor is internally set at 0 2 An
8. 3B as an integral discriminator is not limited to this type of detector Other sources of fast negative pulses in the range of 0 to 10 V can be used as inputs for the integral discriminator In the CF technique the time derivation is insensitive to pulse height variations for input signals with a given fixed rise time Their signal amplitudes must not exceed the operating range of the instrument There are two general system arrangements in which the 583B will be used most often 1 the fast timing coincidence or measurement system and 2 the fast slow system Each of these systems are explained in the following sections 5 2 FAST SYSTEM Figure 2 a shows the instruments required for a simplified fast timing coincidence system Each CF discriminator simultaneously generates the timing information and determines the energy range of interest If two detected events fall within the selected CF Diff Oise a energy ranges and are coincident within the resolving time selected for the coincidence unit the time to pulse height converter TPHC is gated on to accept the delayed precise timing information Thus the TPHC will process start stop signals only if these events are of the correct energy and coincident The CF discriminators are operated in differential mode for this application so they can be used for energy range selection The maximum range of coincident signals that will gate the TPHC is set by the fast coincide
9. Model 583B Constant Fraction Differential Discriminator Operating Manual Printed in U S A ORTEC Part No 931002 1209 Manual Revision D 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 mu
10. and the NIM fast logic output signals are designed for termination in 50 A slow positive SCA output is also furnished with an output impedance of 10 O Although input pulses can range from 0 to 10 V the discriminator levels range from 30 mV to 5 V This discriminator range is adequate for most applications 1 1 DISCRIMINATION AND SINGLE CHANNEL ANALYSIS The 583B has a front panel toggle switch that lets you choose between integral INT and differential DIFF discriminator When the 583B is operated as an integral discriminator integral mode each input pulse that exceeds the adjusted lower level threshold set on the 583B front panel causes a set of timing output signals to be generated To generate the timing output signals in differential mode the input signal must exceed the lower level threshold and must not exceed the upper level threshold for approximately 10 ns after the Constant Fraction zero crossing time This is the principle of fast single channel analysis NOTE In differential mode you must set the lower level threshold to a lower value than the upper level threshold or the 583B will not generate a timing output signal Other features of the 583B include slow rise time reject function e Avariable width blocking one shot The front panel SRT setting gives you a slow rise time reject feature that inhibits the discriminator response to input signals that would cause leading edge timing
11. elay is added the resulting bipolar signal at the CF MON output will cross the baseline at a time that corresponds to the peak amplitude previously observed with the attenuated and undelayed signal A useful empirical formula for the initial trial selection of the external shaping delay is t 1 1 t 0 7 ns where tis the 10 90 rise time of the anode pulses e Walk adjustmentcan then be set while observing the delayed CF MON signal on a fast oscilloscope triggered externally by a timing output signal from the 583B The WALK potentiometer should be adjusted so that the bipolar constant fraction signals for all amplitudes cross through the baseline at approximately the same time Figure 1 a illustrates the anode signals from an RCA 8850 PMT with a 1 in x 1 in KL236 scintillator and source Figures 1 b and c show the resulting delayed CF MON signal seen on a sampling oscilloscope triggered by the 583B timing output The CF shaping delay and walk adjustment have been set properly and the spread in the zero crossing time is less than 100 ps 4 OPERATION The 583B accepts negative input signals in the range of to 10 V For each input pulse that satisfies the 583B s logic criteria four output logic pulses are initiated simultaneously e Two timing output signals from the front panel TIMING OUTPUTS connectors These are separate negative NIM fast logic pulses nominally 5 ns in width A slow po
12. nce unit The histogram of timing signal differences is accumulated in the multichannel analyzer MCA 5 3 FAST SLOW SYSTEM Figure 2 b is the block diagram for a typical fast slow timing measurement system In this system the CF discriminators are operated in integral mode Output signals from these discriminators occur at the count rate associated with the single events that exceed the 583B s LL threshold setting This count rate can be an order of magnitude greater than the coincidence rate at which the TPHC is strobed Note however that the TPHC in this system is strobed not gated and the converter must handle the full singles rate In this system the energy selection and coarse coincidence criteria are determined in the slow linear side channels by the timing SCA units Datay Line Timing SCA Amp b Fig 2 Typical Fast a and Fast Slow b Timing Coincidence Systems for Gamma Gamma Measurements with Scintillators and PMTs 6 5 The following publications give more information on typical coincidence measuring systems in which the 583B can be extremely useful In addition see the reference tutorial sections ofthe ORTEC catalog which you can obtain either in print or on our website 1 Bedwell and T J Paulus New Constant Fraction Timing System with Improved Time Derivation Characteristics IEEE Trans Nucl Sci NS 23 1 234 243 1976 2 M O Bedwell and T J Paulu
13. nty should follow 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 2009 Advanced Measurement Technology Inc All rights reserved ORTEC is a registered trademark of Advanced Measurement Technology Inc other trademarks used herein are the property of their respective owners 5 ii SAFETY INSTRUCTIONS AND SYMBOLS 1 7 0 SAFETY WARNINGS AND CLEANING INSTRUCTIONS Te DESCRIPTION i dad ete ilar BA ee pure Us entrer mper SEE 1 1 DISCRIMINATION AND SINGLE CHANNEL 5 1 2 CONSTANT 1 1 3 INPUT OUTPUT CHARACTERISTICS
14. or operation is designed for rack mounting If the equipment is rack mounted there must be adequate ventilation to prevent any localized heating in the 583B above the maximum limit of 50 C 323 3 2 POWER CONNECTION Turn off the bin power supply before inserting or removing any modules To ensure proper operation check that the dc voltage levels of the power supply are correct after all modules have been installed in the bin ORTEC bins and power supplies include convenient monitoring test points on the power supply control panels 3 3 INPUT CONNECTION The 583B s front panel input connector accepts negative input pulses This input is terminated internally in 50 O Connect the negative input signal source to this connector through a 50 O coaxial cable 3 4 OUTPUT CONNECTIONS The primary outputs of the 583B are the NIM standard fast negative logic signals from the front panel TIMING OUTPUTS BNC connectors The circuits driving these two connectors are separate so each timing output can be used independently Each negative NIM output used must be terminated in 50 O and 50 O cable must be used for the interconnections Unused outputs do not need termination The rear panel SCA OUT output provides a NIM standard slow positive pulse that is initiated simultaneously with the timing outputs on the front panel This output can be used with instruments such as counters or ratemeters that require positive input signals In mo
15. ors These are separate negative NIM fast logic pulses nominally 5 ns in width A slow positive output through a rear panel BNC e The blocking output from the front panel BK OUT connector This is a negative current pulse similar to a NIM fast logic pulse except that the width is determined by the front panel WIDTH control potentiometer The width of the blocking output is set by the period of the internal blocking one shot which can range from 15 ns to 21000 ns In addition an upper level output pulse is generated when the internal upper level discriminator is triggered by an input signal This is a NIM standard fast negative logic pulse and is generated in both differential and integral modes 2 SPECIFICATIONS 2 1 PERFORMANCE INPUT PULSE Accepts negative input pulses from to 10 V without saturation input protected against overload reflections lt 10 for input risetime gt 2 ns DISCRIMINATOR RANGES Upper Level 30 mV to 5V Lower Level 30 mV to 5 V THRESHOLD INTEGRAL NONLINEARITY lt 0 5 of full scale THRESHOLD INSTABILITY lt 0 1 mV C 0 50 C TIME WALK lt 75 ps for 100 1 dynamic range integral mode with external shaping delay 2 ns input risetime lt 1 ns input pulse width 10 ns threshold 30 mV PROPAGATION DELAY Nominally 18 ns with ex ternal shaping delay 2 ns BLOCKING WIDTH Variable from 15 to 1000 ns MINIMUM PULSE PAIR RESOLUTION 50 ns for input
16. out saturation 50 direct coupled input protected against overloads reflections lt 10 for input rise time 22 ns 2 4 OUTPUTS TIMING Two front panel BNC connectors provide simultaneous NIM standard fast negative logic signals BLOCKING BK Front panel BNC connector pro vides a NIM standard fast negative logic signal that occurs simultaneously with the timing outputs inhibits further timing pulses from being generated during the blocking period variable from 15 to 1000 ns POSITIVE SCA Rear panel BNC connector provides a NIM standard slow positive logic signal Occurs simultaneously with timing outputs UPPER LEVEL UL Rear panel BNC connector provides a NIM standard fast negative logic signal Occurs as the leading edge of the input signal crosses the UL threshold 2 5 ELECTRICAL AND MECHANICAL POWER REQUIRED 12 V 120 mA 6 V 0 mA 6 V 650 mA 12 V 80 mA WEIGHT Net 0 85 kg 1 9 Ib Shipping 1 85 kg 4 1 Ib DIMENSIONS NIM standard single width module per DOE ER 0457T U S NIM Committee May 1990 Standard NIM Instrumentation System NTIS U S Department of Commerce Springfield Virginia 22161 3 INSTALLATION 3 1 GENERAL The 583B power requirements must be furnished from a NIM standard bin and power supply such as the ORTEC Model 4001A 4002D Series Note that 6 V power is required in addition to 12 V The bin and power supply into which the 583B will normally be installed f
17. s Constant Fraction Differential Discriminator for Use in Fast Timing Coincidence Systems presented atthe IEEE Nucl Sci Symposium Washington D C October 1978 3 W H Hardy II and K G Lynn A New Approach to Timing the Fast Fast System EEE Trans Nucl Sci NS 23 1 229 233 1976 BIN MODULE CONNECTOR PIN ASSIGNMENTS FOR AEC STANDARD NUCLEAR INSTRUMENT PER DOE ER 0457T Pin N 16 17 18 19 20 21 22 Function 3 V 3V Spare Bus Reserved Bus Coaxial Coaxial Coaxial 200 V dc Spare 6 V 6V Reserved Bus Spare Spare Reserved 12 V 12V Spare Bus Reserved Bus Spare Spare Reserved Pin 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 Function Reserved Reserved Reserved Spare Spare 24 V 24 V 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 Model 4001A and 4001C Modular System Bins
18. sitive NIM output through a rear panel BNC e The blocking output from the front panel BK OUT connector This is a negative current pulse similar to a NIM fast logic pulse except that the width is determined by the front panel WIDTH control potentiometer The width of the blocking output is set by the period of the internal blocking one shot which can range from 15 ns to gt 1000 ns NOTE For optimal walk and jitter performance the CF MON output should always be terminated into 50 O Either view the CF MON signal with a 50 input scope or place a 50 O terminator on the CF MON output 4 1 DIFFERENTIAL MODE The LL threshold must be set to a lower value than the UL threshold or the 583B will not generate a timing output signal In addition the input signal must not exceed the UL threshold for approximately 10 ns after the CF zero crossing time Each of the threshold controls has a range of 30 mV to 5 V Each input pulse that exceeds the UL threshold generates an UL output through the rear panel connector The UL output occurs when the leading edge of the input signal exceeds the UL threshold 4 2 INTEGRAL MODE To generate a timing output the input signal must exceed the LL threshold The UL inhibit function is not used as the criterion for a timing output pulse A UL eee 500 mV div a 20 mV div output pulse is generated when the input signal exceeds the UL threshold
19. st applications the interconnection can be made with 93 cable terminated in 100 Q or more 3 5 CF DELAY CABLE The CF time derivation circuit is not complete until an external length of 50 O cable has been connected between the two DELAY connectors on the front panel The total CF shaping delay is equal to the external CF shaping delay Lx plus approximately 0 7 ns We expect that the 583B will be used primarily in fast timing or counting experiments with scintillators and photomultiplier tubes PMTs In these applications the total CF shaping delay is selected so that the zero crossing of the bipolar timing signal occurs when the attenuated undelayed portion of the CF signal has reached its maximum amplitude Therefore the zero crossing occurs at the same fraction of the input pulse height regardless of the amplitude of the input signal Selecting the CF shaping delay for best timing performance with a given scintillator and PMT usually requires experimentation e Applythe randomly generated signals from the PMT anode to the 583B input e Each of the two DELAY connectors should be terminated with a 50 Q terminator e The CF MON signal can then be observed on a fast oscilloscope bandwidth 300 MHZ terminated in 50 O and triggered internally The CF MON signal then represents the attenuated undelayed portion of the CF signal with no delayed signal subtracted from it When the appropriate length of CF shaping d
20. st pass a stringent set 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 Rev 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 warra
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