Model 551 Timing Single-Channel Analyzer Operating and
Contents
1. reset trigger depends on both events having occurred The duration of the low signal from IC7 6 is the propagation time for the reset of latch IC6 13 and IC4 11 Since the reset circuit is dependent upon the lower level discriminator and since in the Normal and Integral modes it is possible to adjust the upper level threshold for a response at less than the lower level threshold this combination could result in a single response through the UL Out without its latch being reset until the lower level threshold is also exceeded by an input This condition will not exist in the Window mode since it is not possible to set the UL below the LL level 5 11 DELAY CIRCUIT When 1 7 12 goes low Section 5 9 IC8 13 goes high and triggers the delay circuit The delay circuit includes Q15 Q16 Q19 Q20 and Q21 and their associated circuitry When the trigger is furnished to 10 Q15 Q16 is cut off and held in the off state by the signal from Q21 and C45 Q16 then returns to its normally conducting condition when C45 is recharged by current through either Q19 or Q17 When Q16 is turned on again the negative output transition triggers the SCA outputs unless prevented by the external strobe circuit For internal strobe operation the emitter for Q19 can be set high with S3 set at 1 11 Us or low with 53 set at 1 1 1 Us Potentiometer R115 the Delay control on the front panel combines with the Q19E level to determine the curre2. will remain high whether the upper level discriminator is triggered or not But if the switch selects either Normal or Window for differential single channel operation a response in IC3 will furnish a low signal from 1C7 8 to inhibit a response in IC7 12 and prevent an SCA output signal from being generated 5 8 CONSTANT FRACTION CIRCUIT The input signal is furnished through R2 into a peak detect circuit formed by Q1 through 05 and C10 During the time of the input pulse the capacitor is charged The verse current path is cut off so the peak amplitude of the input pulse remains on C10 until it is discharged at a later time The peak amplitude of the input pulse is furnished through a unity gain buffer amplifier Q8 Q9 and Q10 The front panel Walk Adj control R36 provides a fine adjustment of the offset of this amplifier and is adjusted for its dynamic function to minimize walk in the time significant output pulses The output of the buffer amplifier is furnished through R33 and R31 a divide by 4 attenuator From this circuit 2596 of the peak amplitude of the signal input pulse is furnished to the inverting input of IC5 Integrated circuit IC5 is the CF discriminator The inputs at its pins 3 and 4 are indicated in Fig 4 1 During operation the ICS package is triggered at the beginning of each input pulse as soon as the 50 level at pin 4 exceeds the 25 level at pin 3 by just a few millivolts Then during decay of th
3. The delay interval can be adjusted within the range of 0 1 to 11 Us using front panel controls If the pulses of Fig 4 1 were furnished to a 551 that was set for its Normal or Window differential mode time significant SCA output pulses would be generated for each of the first two input pulses but none would be generated for the third because its amplitude was greater than the upper level threshold If the pulses were furnished to a 551 that was set for its integral mode a time significant output pulse pair would be generated for each of the three input pulses In either mode of operation an LLD and a ULD output will result when the corresponding discriminator thresholds exceeded by the input pulse amplitude The adjusted lower level threshold is furnished either from the front panel Lower Level control or from an external source through the rear panel LL Ref connector the alternate selection is made with the rear panel LL Ref toggle switch either Int for the front panel control or Ext for the rear panel BNC In either case the range is from 0 to 10 V measured from chassis ground of the input signal The adjusted upper level threshold is determined by the setting of the front panel Upper Level or Window control and by the front panel mode selector toggle switch When the switch is set at either Int or Nor the range of the variable control is from 0 to 10 V measured from chassis ground When the toggle switch is set at
4. mV 4 Remove the jumper between Q4C and R28 5 With no input signals adjust R17 as necessary to obtain O V again at the buffer amplifier output Q9C 6 3 FACTORY REPAIR This instrument can be returned to the ORTEC factory for service and repair at a nominal cost Our standard procedure for repair ensures the same quality control and checkout that are used for a new instrument Always contact the Customer Service Department at ORTEC 865 482 4411 before sending in an instrument for repair to obtain shipping instructions and so thatthe required Return Authorization Number can be assigned to the unit Write this number on the address label and on the package to ensure prompt attention when the shipment reaches the ORTEC factory 6 4 TABULATED TEST POINT VOLTAGES The following voltages are intended to indicate the typical dc voltages that can be measured on the printed circuit In some cases the circuit will perform satisfactorily even though due to component tolerances some voltages may differ slightly from those that are tabulated in Table 6 1 Therefore the voltages that are listed should not be considered absolute but rather are intended as an aid in troubleshooting All voltages were measured with no input signal and with the front panel switch set for integral mode The level at Q20B is dependent upon the setting of the delay range switch S3 Location R38 R 39 junction R43 R42 junction Q8B Q9B
5. output Delay as selected by the front panel controls LL Out Rear panel BNC connector provides positive NIM standard output nominally 5 V 500 ns wide lt 10Q output impedance Output occurs as leading edge of linear input crosses the LL threshold UL Out Rear panel BNC connector provides NIM standard output nominally 5 V 500 ns wide lt 10Q output impedance Output occurs as leading edge of linear input crosses the UL threshold 2 5 RELATED EQUIPMENT The 551 is compatible with all ORTEC amplifiers and other amplifiers having 0 to 10 V positive linear output range 2 6 ELECTRICAL AND MECHANICAL Power Required 24 V 90 mA 12 V 160 mA 24 V 50 mA 12 V 110 mA Dimensions NIM standard single width module 1 35 by 8 714 in per TID 20893 Rev 3 INSTALLATION The 551 must be used in conjunction with an ORTEC 4001 4002 Series Bin and Power Supply or equivalent which is intended for rack mounting Therefore if vacuum tube equipment or any other source of heat is operating in the same rack there must be sufficient cooling air circulating to prevent any localized heating of the transistorized and integrated circuits used throughout the 551 The temperature of equipment mounted in racks can easily exceed the maximum unless precautions are taken the 551 should not be subjected to temperatures in excess of 120 F 50 C 3 1 CONNECTION TO POWER Turn off the Bin Power Supply when inserting or remov
6. 01A and 4001C Modular System Bins
7. EFERENCE INPUT if the LL Ref toggle switch on the rear panel of the 551 is set at Ext the reference level for the lower level discriminator must be furnished through the adjacent LL Ref In BNC connector the 10 turn Lower Level control on the front panel is disconnected An input of 0 to 10 V through this connector corresponds directly to a range of 0 to 10 V for the lower level discriminator threshold If an input is connected to the LL Ref connector and the switch selects Int the signal through the connector is ignored 4 OPERATING INSTRUCTIONS After the 551 has been connected into a system according to the installation information in Section 3 the operating and strobe modes can be selected and the discriminator thresholds can be adjusted as required for each application Figure 4 1 illustrates the timing relationships that will be effective in the 551 operating with internal strobe for each of three possible input pulse amplitudes The first two pulses exceed the lower level threshold without also exceeding the upper level and the third pulse exceeds both threshold levels Superimposed in each of these input pulses in Fig 4 1 is an internally generated signal that rises to 50 of the input peak amplitude and is stretched at that level When the input pulse decays through the 50 level the CF discriminator resets and when delayed by a fixed interval triggers the SCA outputs if the analysis criteria have been satisfied
8. FRACTION CIRCUIT 9 5 9 SGA GAT Eron n ettet ete dee e e e ee ese ee bete bae bee Meta a 9 5 30 BESET CGIRGUNT RUE RU E ECL I E EE xS 10 5 11 DELAY GIRGULT ee Bee ine ee Wi de A Eee ee Ble ees 10 5d2 DG POWER ect est esse Sass ER IS BR 11 6 CALIBRATION AND 1 44 11 GENERAL see ee i eV 11 6 2 CALIBRATION teen R aeg 11 6 32 FAG LORY REPAIR excise sey sae dia ox x es ere dea oss os rs ow Qi OS dee Us deg a e 11 6 4 TABULATED TEST POINT VOLTAGES 11 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 pro
9. G OUT ay did dpa 1 1 ULD OUT l 8146 Fig 4 1 Timing Relationships for Input and Output Pulses for Operation with Internal Strobe 5 CIRCUIT DESCRIPTION 5 1 GENERAL Figure 5 1 is a simplified block diagram of the 551 Timing SCA It shows that each input pulse is furnished to three internal discriminators and also through an attenuate and peak stretch circuit The three discriminators are U L upper level LL lower level and CF constant fraction Each discriminator independently triggers a response when the amplitude of its noninverted input exceeds the amplitude of its inverted input The response of the UL and LL discriminators is latched until an internal reset occurs The CF discriminator is reset again when the input conditions are reversed Reference levels for the UL and LL discriminators set independently for either Integral or Normal mode operation For Window operation the threshold for the UL discriminator is based on the LL setting instead of ground The CF discriminator is triggered at the onset of each input pulse whether its amplitude is sufficient to trigger either of the other two discriminators or not Then the CF discriminator is reset when the amplitude of the input pulse decays through its 50 level because the attenuate and peak stretch circuit ATTENUATE and PEAK STRETCH has generated and maintained this 50 level by that time and furnished it as the discrimin
10. Model 551 Timing Single Channel Analyzer Operating and Service Manual Printed in U S A ORTEC Part No 733450 1202 Manual Revision E 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 p
11. NGE 22221 tese ede due dee bee ede ee 2 2 SPECIFICATIONS tw eese x p ala alata alsa ep 2 2 PERFORMANCE ne are e ge uoa urea Ue URS une Rud ies 2 2 2 AGONTROLS D cet cA E E t te 3 CUM II Eu 3 2 4 VOUT PUUS laces celecteteteceigtedacedgtetacaigsede ca 3 2 5 RBEEATED EQUIPMENT 5 ette nt ntt setae t level 4 2 6 ELECTRICAL AND MECHANICAL 4 TALL ATION et e de tete pte ue oe OR Ali a cA ast nae aoe 4 SA CONNECTION TO POWER bee eee eee eee nea ea eae eee tbe 4 3 2 CONNECTION FROM LINEAR AMPLIFIER D RE 4 3 3 OUTPUT CONNEGTIONS ao aca rue uc sv rv qug vp 4 3 4 LOWER LEVEL REFERENCE INPUT 2 5 4 OPERATINGINSTRUGTIONS DEBERE EU EPUM 5 b CIRCUIT DESGRIETION ceat ete ete ea ae 7 ba GENERA D 7 5 2 INTEGRATED GIRGUITS A A e Lv Ve v s 7 5 3 LOWER LEVEE BIAS rce ERREUR ERR ee eee 8 5 4 UPPER LEVEL BIAS eser re peels peste peso ee ele ee epe eee eles 8 5 5 INPUT CIRCUL rtt EE EN MES 8 5 6 LOWER LEVEL DISCRIMINATOR 2 8 5 7 UPPER LEVEE DISCRIMINATOR Ere dra dee dra RAE 9 5 8 CONSTANT
12. Q10A G Q10A S Q10B G Q11B Q12B 012 0138 0148 14 014 Q15B Q15C 0168 Q16E Q16C Te O von 0 12 Table 6 1 Typical dc Voltages 5 02 Q17B 1 4 6 5 02 Q17E 1 4 9 0 6 0188 4 11 0 6 Q20B S3 1 11 1 4 14 20 5 020 53 1 1 1 1 5 3 1 2 Q21E ICB 4 1 2 Q22B 1 5 6 0 5 022 1 5 11 0 5 023 IC6 9 1 2 Q23E 6 10 16 3 025 1 6 13 15 0 Q25C 8 0 Q26C 1C7 12 1 2 Q26E 1C8 1 0 0288 1C8 2 1 3 Q28E IC8 4 1 0 O29E IC8 10 1 7 Q29C IC8 13 0 4 Q32B IC8 14 1 3 Q338 IC9 3 1 2 IC3 1 1C9 6 0 IC3 3 9 8 1 5 1C3 6 9 11 12 IC3 11 1 10 1 0 5 1 3 14 10 4 1 1 ICA 1 D8A 0 6 4 3 Voltage 13 Table 1 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 6 11 6V 12 Reserved bus 13 Spare 14 Spare 15 Reserved 16 412V 17 12V 18 Spare bus 19 Reserved bus 20 Spare 21 Spare 22 Reserved 41 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 40
13. Win the range of the variable control is 0 to 1 V measured above the adjusted lower level threshold When the rear panel toggle switch for the Strobe source selects Ext operation of the 551 is the same as for Int except for the time at which an SCA output is generated For this mode of strobe output the external strobe must be furnished after the CF LLO CF TRIGGER Delay adjusted in range of 0 1 to 11 ps Delay trigger time and before an automatic reset and the SCA output signals are furnished promptly at the strobe time The time window during which the strobe can be accepted is measured from the CF trigger time and is either 5 or 50 Us when the front panel delay toggle switch selects 1 1 1 the time window is 5 Us or when the switch selects 1 11 the time window is 50 us If no strobe is furnished within the time window the internal logic is reset without generating an output through the SCA circuits For optimum time significant SCA output timing the front panel Walk Adj must be trimmed to the combined effects of the input shaping and its time constants and of the expected dynamic range of operation Using a duplicate of the minimum and maximum amplitudes for shaped input pulses set the control to provide the minimum walk variation of time of occurrence vs input amplitude DIFF SCA POS OUT DIFF SCA NEG OUT INT SCA POS OUT l INT SCA NE
14. acceptance intervals is made with the front panel switch that is marked for adjustable delay intervals 1 1 1 and 1 1 1 For any mode of operation a signal is furnished through the LL Out connector on the rear panel when the lower level discriminator is triggered on the leading edge of the input signal Also a signal is furnished through the UL Out connector on the rear panel when the upper level discriminator is triggered on the leading edge of the input signal Each of these outputs is a NIM standard positive signal that can be used for any desired external application 1 4 LOWER LEVEL REFERENCE A rear panel 2 position locking toggle switch selects either the front panel Lower Level control or the voltage signal applied through the rear panel LL Ref connector as the reference level for the lower level discriminator This permits flexibility in operation where an external reference source can furnish the lower level threshold from a stepped or sliding voltage source to automatically sweep the SCA response through a spectral range of 0 to 10 V The selected source for the Lower Level Reference is effective for all three operating modes 2 SPECIFICATIONS 2 1 PERFORMANCE Dynamic Range 200 1 Pulse Pair Resolving Time Output pulse width plus Delay as selected by the front panel Delay controls plus 100 ns for fast NIM output or plus 200 ns for positive NIM output Minimum resolving time for negative output 220 ns
15. ass 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 warrant
16. ator reference level The SCA gate is triggered when the CF discriminator is reset if at that time the LL discriminator has been triggered and the UL discriminator either has not been triggered for differential operation or is ignored for integral operation Thus the gate responds to both logical conditions and input pulse time significance If the SCA gate responds it strobes a delay circuit that then generates the SCA outputs at the end of the delay interval The simplified diagram does not show the use of an external strobe for this output see Section 5 11 5 2 INTEGRATED CIRCUITS The nomenclature used to identify integrated circuit pack ages in this manual is defined below for the example IC5 4 where IC integrated circuit 5 reference designation 4 pin number UL Out OUTPUT GENERATOR LL Out OUTPUT GENERATOR OUTPUT GENERATOR Pos Out Neg Out CURRENT SWITCH 8146 Fig 5 1 Simplified Block Diagram of the 551 Timing SCA Any portion of an IC package can be designated by its output pin number in this example the portion of IC5 that includes pin 4 as an output is identified uniquely 5 3 LOWER LEVEL BIAS The threshold for the lower level discriminator is adjusted with the front panel Lower Level control R43 or is furnished as a dc level through CN3 on the rear panel Switch S4 on the rear panel selects which of these sources is effective for bias control For th
17. be furnished when the discriminator returns to quiescent and the CF discriminator is also reset these conditions occur on the trailing edge of the input pulse The signal from IC4 11 is furnished through IC8 4 to generate an LL Out signal through CN8 on the rear panel when the input signal rises through the LL threshold The output generator uses Q25 Q26 and 027 to generate the positive output pulse with a width of about 500 ns Until latch 6 13 and IC4 11 is reset the high level to pin 2 of SCA gate IC7 12 arms the gate to permit response if its pins 1 and 13 go high See Section 5 9 SCA Gate 5 7 UPPER LEVEL DISCRIMINATOR Integrated circuit package IC3 is the upper level discriminator It is identical to IC4 discussed Section 5 6 above except that its output at pin 9 is not used If the amplitude at pin 3 increases above the threshold level at pin 4 IC3 triggers and switches the output at IC3 11 to its high state This output at pin 11 latches through IC6 10 until a reset is furnished from 1 7 6 The reset will be furnished when both the lower level and CF discriminators have been reset as discussed in Section 5 6 At the trigger time on the leading edge of the input signal when IC3 11 goes high an output through CN4 the UL Out connector is generated through 8 1 Q22 023 024 The positive output pulse has a width of about 500 ns if switch S1 is set at Int the output of gate IC7 8
18. cts one of three operating modes Integral LL sets a single discriminator threshold 0 to 10 V and UL response is ignored for SCA outputs Normal UL and LL are independently adjustable levels 0 to 10 V differential mode operation Window LL sets the baseline level 0 to 10 V and UL sets the window width 0 to 1 V differential mode operation Delay Range Front panel locking toggle switch selects delay ranges of 0 1 to 1 1 Us or 1 0 to 11 Us for internal strobe or automatic reset without SCA output after 5 or 50 Us for external strobe Delay Front panel 10 turn potentiometer for continuous adjustment of output delay over selected range In the external strobe mode the delay control adjusts the automatic reset time from 5 us to 50 us Walk Adjust Front panel screwdriver adjustment for precise setting of walk compensation LL Ref Mode Rear panel two position locking toggle switch selects either the front panel LL potentiometer or the voltage signal applied to the rear panel LL Ref Ext connector as the LL discriminator reference threshold Strobe Rear panel 2 position locking toggle switch selects either Internal or External source for the SCA output signal strobe function 2 3 INPUTS Signal input Front panel dc coupled BNC connector accepts positive unipolar or bipolar signal 0 to 10 V linear range 12 V maximum width gt 100 ns 1000 input impedance Rear panel ac coupled BNC connector accepts positive unipo
19. d lower level becomes effectively the base above which the upper level is added and the result is a window of 0 to V between the lo ver level and upper level thresholds referred to the input pulse amplitude The gain for the level from IC2 7 through IC 1 1 is unity 5 5 INPUT CIRCUIT This analog input signal can be furnished through either CN1 on the front panel or CN2 on the rear panel The signal is then furnished to dividers R3 R4 and R47 R48 and 50 of the input amplitude is applied to the noninverting inputs of both the UL and LL discriminators IC3 and ICA The input range of 0 to 10 V divided by two for an effective range of 0 to 5 V at the discriminator inputs is directly equivalent to the range of threshold levels described in Sections 5 2 and 5 3 above The input signal through either the front panel dc coupled circuit or the rear panel ac coupled circuit can be monitored at test point TP1 on the front panel 5 6 LOWER LEVEL DISCRIMINATOR integrated circuit package 4 is the lower level discriminator As long as the input level at its pin 3 does not exceed the level at pin 4 the output at its pin 9 is high When the amplitude of the input signal at pin 3 increases above the threshold level at pin 4 IC4 triggers and reverses the levels at its pins 9 and 11 VVhen 4 11 goes high 6 13 goes low and latches 1 4 11 in the high state until a reset is furnished from 1 7 6 The reset will
20. ds of USAEC Report TID 20893 Rev An ORTEC 4001 4002 Series Bin and Power Supply provides all the necessary power through the rear panel power connector Al signal levels and impedances are compatible with other ORTEC NIM modules The 551 has a front panel switch that selects the integral mode of operation or either of two types of differential single channel analysis modes For Normal operation each of the discriminator levels is adjusted independently through the full dynamic range of 0 to 10 V For Window operation the range of the lower level control is 0 to 10 V and the range of the upper level or window control is the adjusted lower level plus 0 to 1 V 1 2 MODES OF OPERATION Integral Mode Operation In the integral mode the 551 generates an output through the SCA connector on the rear panel and through both the Pos Out and Neg Out connectors on the front panel if the input pulse amplitude exceeds the adjusted lower level threshold the range is 0 to 10 V Normal Mode Operation In the normal mode the 551 generates an output through the SCA connector on the rear panel and through both the Pos Out and Neg Out connectors on the front panel if the input pulse amplitude exceeds the adjusted lower level but does not exceed the adjusted upper level threshold In this mode each threshold is adjusted independently in the range of 0 to 10 V and the upper level must be set higher than the lower level to permit the SCA outputs to b
21. duct 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 liquid to dampen the cloth or applicator Allow the instrument to dry completely before reconnecting it to the power source vi ORTEC MODEL 551 TIMING SINGLE CHANNEL ANALYZER 1 DESCRIPTION 1 1 PURPOSE The ORTEC 551 Timing Single Channel Analyzer provides a versatile group of related signal derivation functions It can be used as either a single channel analyzer or as integral discriminator The princi
22. e generated Window Mode Operation In the window mode the 551 generates an output through the SCA connector on the rear panel and through both the Pos Out and Neg Out connectors on the front panel if the input pulse amplitude exceeds the adjusted lower level threshold but by an amount that is less than the adjusted window width The range of the lower level control is 0 to 10 V and the range of the upper level control is 0 to 1 V above the lower level This mode is especially adapted to high resolution spectroscopy because the very narrow windows that are required can be obtained easily and reproducibly 1 3 OUTPUT PULSE TIMING The SCA Pos Out and Neg Out pulses from the 551 are generated at a delay with internal strobe following the precise constant fraction time recognition which occurs at 50 of the peak amplitude on the trailing edge of the input pulse The delay interval is adjustable through two ranges selected by a front panel switch the low range is 0 1 to 1 1 Us and the high range is 1 0 to 11 Us The front panel Delay control is a 10 turn precision potentiometer that is marked in 1000 increments that read the adjusted delay directly in the units When external strobe is used the SCA Pos Out and Neg Out pulses from the 551 are furnished promptly at the strobe time To be effective the strobe s leading edge must occur within about 5 Us or 50 Us after the constant fraction recognition The choice between the two
23. e input pulse the level at pin 4 drops down through the level at pin 3 at 5096 of the peak amplitude which is a dependable and precise time in a shaped linear pulse and IC5 is reset At reset IC5 9 goes high to drive pin 9 of IC8 low and to switch IC6 1 from low to high R77 and C34 provide a slight delay before IC6 1 reaches a high level and during this short interval ICS 10 goes high The level at 8 10 is one of the three inputs to SCA Gate IC7 12 The CF discriminator is triggered and then reset during each input pulse including noise pulses The only input pulses that will use the time significant CF reset are those that also trigger the LL discriminator 5 9 SCAGATE Integrated circuit IC7 12 is the SCA Gate When all three of its inputs are high the output switches low and this starts generation of an output through the SCA Out the Pos Out and the Neg Out connectors The signal at IC7 13 is high unless the upper level discriminator has been triggered and switch SI is set at either Nor or Win the differential mode of operation A response by the UL discriminator with differential operation will inhibit a response in IC7 12 The signal at IC7 2 is high from the time the LL discriminator is triggered until an internal reset is generated by IC7 6 and this will not occur before the reset of the CF discriminator Thus a response by the LL discriminator is a prerequisite to enable gate IC7 12 The sig
24. e input pulses decay slowly the ac coupling that is available through the rear panel AC Input BNC can be used instead Either input circuit accepts positive unipolar pulses or bipolar pulses the positive lobe will be analyzed into an input impedance of gt 1000Q When long cables more than about 4 ft are used to connect the amplifier output to the 551 input cable termination may be necessary in order to prevent reflections match the cable impedance with a terminator at the 551 input in such cases 3 3 OUTPUT CONNECTIONS The logic output pulses that are generated when input pulses satisfy the amplitude and logic requirements of the 551 are available through both front and rear panel BNC connectors NIM standard fast negative signals are available through the front panel Neg Out BNC NIM standard slow positive signals are available through both the front panel Pos Out and the rear panel SCA Out connectors When the 551 is set for either differential single channel mode normal or window the logic output pulse means that an input pulse amplitude is sufficient to trigger the lower level discriminator without also triggering the upper level discriminator When the 551 is set for its integral mode of operation the logic output means that an input pulse amplitude is sufficient to trigger the lower level discriminator triggering of the upper level discriminator does not affect the output The time when all three SCA logic output s
25. e internal bias circuit R47 is a potentiometer mounted on the printed circuit that adjusts the minimum level for the front panel control The actual range of R43 is then from a few millivolts to about 5 V The adjusted level is buffered through 2 7 and inverted through operational amplifier 2 1 with a gain of unity and furnished to the inverting input of IC4 the lower level discriminator For the external bias circuit a dc level between 0 and 10 V can be furnished through CN3 and divided by R44 and R45 The result that is selected with switch S4 is then furnished through the same buffering and coupling network to the lower level discriminator 5 4 UPPER LEVEL BIAS The threshold for the upper level discriminator is adjusted with the front panel Window or Upper Level control R38 The range for this control is 0 to 5 V The adjusted level is buffered through ICI 7 and furnished through either R55 or R52 through operational amplifier IC1 1 and to the inverting input of upper level discriminator IC3 When switch SI is set at either Integrate or Normal the gain of 1 for this adjusted bias signal is 1 0 when the switch selects Window the gain is reduced to 0 1 and the effective range of the Window control is thus reduced by a factor of 10 Also when the switch selects Window the level that is furnished frorn IC2 7 for the lower level discriminator is also furnished through R50 and IC 1 1 Thus the adjuste
26. e the outputs If Q16 is turned on by automatic reset without a strobe input gate IC9 8 prevents any output generation from occurring The base level for Q16 is very sensitive so a temperature compensating network is connected between this point and ground 5 12 DC POWER Input power from the bin and power supply is accepted through the module Connector on the rear panel The 551 operates on 90 mA through the 24 V circuit 160 mA through the 12 V source 50 mA f rom 24 V and 110 mA from 12 V 11 Internally the 12 V source is furnished to a circuit that uses Q32 and 033 to generate a regulated 5 V level The 5 V level is used in the integrated circuit packages that are in the 551 circuits 6 CALIBRATION AND MAINTENANCE 6 1 GENERAL The basic performance of the 551 Timing SCA can be inferred from its operating responses If the unit fails to respond properly at any time use the information in Section 5 to identify the probable fault 6 2 CALIBRATION There is a provision for the calibration of the CF reference circuit Potentiometer R17 mounted on the printed circuit permits this calibration Use the following procedure 1 Connect a jumper between Q4C and R28 This ties the input to the buffer amplifier at ground 2 Set potentiometer R17 fully counterclockwise as viewed from the top 3 Measure the output of the buffer amplifier at Q9C Adjust front panel Walk Adj R36 as necessary to obtain OV 1
27. for positive output 800 ns Threshold Temperature Instability lt 0 01 C of full scale 0 to 50 C using a NIM class A power supply referenced to 12 V Discriminator Nonlinearity lt 0 25 of full scale integral for both discriminators Delay Temperature Instability lt 0 03 C of full scale 0 to 50 C Delay Nonlinearity lt 2 of delay range Window Width Constancy lt 0 1 variation of full scale window width over the linear 0 to 10 V range Minimum Input Threshold 50 mV for Lower Level discriminator Time Shift vs Pulse Height Walk WALK ns Dynamic System System Range A B 10 1 1 0 2 0 50 1 2 5 4 0 100 1 3 0 8 0 System A Using an ORTEC 460 Amplifier single delay line mode integrate lt 0 1 Us with delay line 1 Us System B Using an ORTEC 471 or 472 Amplifier unipolar output with 0 5 Us shaping time Input from ORTEC 419 Pulser 2 2 CONTROLS Lower Level Front panel 10 turn potentiometer adjustable from 0 to 10 V when the rear panel LL Ref mode switch is set on Int determines the threshold setting for the Lower Level discriminator When the LL Ref mode switch on the rear panel is in the Ext position this control is ineffective Window or Upper Level Front panel 10 turn potentiometer determines the window width 0 to 1 V in the Window mode or the Upper Level 0 to 10 V threshold in the Normal and Integral modes Int Nor Win Front panel 3 position locking toggle switch sele
28. ignals are made available is the result of either an internal or an external strobe selected by a rear panel switch When the switch selects Int the strobe originates from the constant fraction trigger at 50 amplitude on the decay of the positive input pulse This strobes a delay circuit with the delay interval adjusted with front panel controls between 0 1 and 11 Us and the outputs occur at the end of the delay interval When the rear panel switch selects Ext A NIM standard positive logic pulse must be furnished through the Strobe In BNC on the rear panel and the outputs occur at the strobe time if a strobe is not furnished within 5 or 50 Us selected by front panel delay toggle at 1 1 1 or 1 11 respectively the internal logic is reset without generating an output Separate logic outputs are available through the rear panel to indicate when on the leading edge of an input pulse each of the two discriminators is triggered These responses can be used to monitor the discriminator levels during adjustment to be counted in external scalers to provide subgroup routing in a multichannel analyzer or for any other applications as desired Each logic output for LL Out and UL Out is a NIM standard slow positive pulse that is compatible with all ORTEC scalers counting rate meters and other instruments The output impedance through each output path is sufficiently low to drive as many as ten paralleled 10000 inputs 3 4 LOWER LEVEL R
29. ing modules The ORTEC NIM modules are designed so that it is not possible to overload a properly operating power supply with a full complement of modules in the bin Since however this may not be true when the bin contains modules other than those of ORTEC design power supply voltages should be checked after the modules have been inserted The 4001 4002 has test points on the power supply control panel to monitor dc voltages When using the 551 outside the 4001 4002 Bin and Power Supply be sure that the power extension cable that is used properly accounts for the power supply grounding circuits that are provided according to the recommended AEC standards outlined in 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 in remote cable installations Be careful also to avoid ground loops when the module is operated outside the bin 3 2 CONNECTION FROM LINEAR AMPLIFIER Either of two inputs in the 551 can be used for the analog signals that are furnished from a linear amplifier The BNC on the front panel accepts input signals through a dc coupled path the rear panel BNC accepts signals through an ac coupled path The circuit through the DC Input on the front panel is generally preferred However if there is any dc baseline offset if signal amplitudes exceed the 12 V maximum limit of the dc circuit or if th
30. lar or bipolar signal 0 to 10 V linear range 100 V maximum width 0 2 to 10 us 100Q input impedance LL Ref Ext When the rear panel LL Ref mode switch is on Ext the rear panel LL Ref Ext BNC connector accepts the Lower Level biasing an input of 0 to 10 V on this connector corresponds to a range of 0 to 10 V for the Lower Level discriminator setting Input protected to 24 V Ext Strobe In When the rear panel Ext int Strobe locking toggle switch is in Ext the rear panel Ext Strobe In BNC connector accepts a positive NIM standard input nominally 5 V 500 ns wide to cause an output to occur from the SCA The external strobe should be given within 5 Us or 50 Us as determined by the front panel Delay control of the linear input At the end of this period the 551 resets its internal logic without producing an output signal if no strobe has been furnished 2 4 OUTPUTS SCA Pos Out Front panel and rear panel BNC connectors provide positive NIM standard output nominally 5 V 500 ns wide 10 Q output impedance For internal strobe output occurs at the mid point of the linear input trailing edge plus the output Delay as selected by the front panel controls For external strobe output occurs at strobe time SCA Neg out Front panel BNC connector provides fast NIM standard output nominally 16 mA 800 mV on 50Q load width 20 ns rise time 5 ns Output occurs at the mid point of the linear input trailing edge plus the
31. nal at IC7 1 is furnished from IC8 10 when the CF discriminator is reset see Section 5 8 Thus for the short duration of the signal high at IC7 1 and if the single channel criteria have been met by signals at IC7 2 and IC7 13 then IC7 12 will go low 5 10 RESET CIRCUIT An internal reset circuit is furnished from IC7 6 going low when all three inputs are high When IC7 6 goes low it resets the latch for the LL discriminator through IC6 13 it resets the latch for the UL discriminator if it has been triggered through IC6 10 and it turns on QI to quickly discharge the storage capacitor CIO in the peak detect circuit At the start of an input signal at the CF trigger response the input of IC7 6 at pin 3 goes low and remains low until just after the CF discriminator is reset the signal from IC6 1 R77 and C34 The signal at pin 4 goes high at the LL discriminator trigger tirne and is latched high through 4 11 until internal reset has occurred The third input to IC7 6 is furnished from the complementary output of IC4 9 and this goes high when 4 is reset The IC4 reset occurs when the input signal amplitude decays back through the adjusted LL threshold From atiming point of view the LL trigger and reset must have both occurred and the CF discriminator must have been reset before all three inputs to IC7 6 can be high simultaneously Either the CF or the LL reset can occur before the other but the
32. nt rate that will recharge C45 and thus determine the recovery time for the delay circuit For external strobe operation the emitter level for Q19 is set in the same manner either low or high by S3 Resistor R114 then combines with the Q19E level to determine the rate that will recharge C45 and thus determine the recovery time at either 5 or 50 Us and Q16 is turned on at the end of this time if an external strobe is furnished through CN5 prior to recovery the input pulse is furnished through Q18 and Q17 to recharge C45 quickly and generate an immediate response by turning on Q16 When 52 selects internal strobe pin 9 of IC9 is held high At the start of the delay interval pin 10 of IC9 goes high and this propagates through IC9 I 1 and IC9 6 to furnish a low to pin of IC10 1 arming this gate At the negative transition from Q16C 9 8 switches high so IC9 3 goes low and triggers the current switch Q13 and Q14 for the Neg Out signal the negative transition also triggers IC10 1 to furnish a negative pulse through 10 4 and start the generation of the Pos Out and SCA Out signals Both of these triggers are terminated by the fast differentiation of R89 and C38 When switch S3 selects External strobe pin 9 of IC9 is held low until a strobe pulse is furnished When the strobe occurs gate IC9 8 initiates the response conditions that are described above and also triggers the recovery of Q16 through Q18 and Q17 to initiat
33. pal output furnished as both a NIM standard fast negative signal and a NIM standard slow positive signal can be used for accurate timing information or can be strobed by an external input In addition separate NIM standard slow positive outputs are furnished separately for each response by the lower level and upper level discriminators in the module When the output signal is internally generated its timing relative to that of the input signal is derived accurately using a time recognition technique called Constant Fraction Discrimination This technique provides unexcelled timing on either unipolar or bipolar signals which displaces less than 3 ns for an input amplitude variation as great as 100 1 This eliminates the degradation of time resolution for varying input amplitudes that is characteristic of leading edge time recognition The 551 accepts either unipolar or bipolar input pulses having either RC or delay line pulse shaping waveforms It examines the amplitude of each input pulse and generates appropriate output pulses separately for SCA LLD and ULD responses For internal strobe operation the SCA output is delayed from the time of recognition at 50 of full amplitude on the trailing edge of the input positive waveform The delay is adjusted on the front panel between 100 ns and 11 Us so that the output time can be normalized to its application The instrument is designed to meet the recommended inter changeability standar
34. y 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 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 WARRANTY eser EE ii SAFETY INSTRUCTIONS AND SYMBOLS 1 4 iv SAFETY WARNINGS AND CLEANING INSTRUCTIONS Tk DESCRIPTION ai eee tee eee i en e dte ei abetted E E ara e eae eR a I EN a Ee 1 TX PURPOSE esu ut st oe ch pt hot opt opt opto opt php ph ct ctu 1 1 2 MODES OF OPERATION eet aetate a ha t a tha ed a e de ect 1 1 3 OUTPUT POLESE TIMING ERREUR as es aS es Bs EUN CR UR 2 1 4 LOWER LEVEL REFERE
Download Pdf Manuals
Related Search