ELENA magnetic longitudinal pickups calibration update D Gamba
ELENA magnetic longitudinal pick-ups calibration update D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 1
Where to go from here (23. 11. 20) • • • Repeat calibration measurement on LNE 00 after head amplifier change Adjust or repair recovered head amplifier Make spare boards of version 2 of the ring buffer amplifiers work done Make a calibration of the ring LPU with comparison of electrostatic BPM system done Revisit on Tuesday the cable delay required between LF and HF pick-up Check how it is done in AD extraction line • L-pad 195 Ohm, 68 Ohm is used in lab for TF measurement • Current divider 1: 1000 in operation with TRIC card • When was last calibration documented and by who? • need timing, RF trains Current divider scheme possible for ELENA, but needs to be very close to • use a filter at the output of the TRIC card Check input impedance of digitizer (50 Ohm confirmed? ) confirmed Software to be defined, also for the delay switching for the combined signal of LF and HF ring pick-up D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 2
Equivalent circuit (with attenuators) missing cable from BI racks • • 60 d. B low pass 6. 6 MHz attenuators represented as T-network low-pass filter 6. 6 MHz, 3 rd order Impedance of coil with FB amplifier from measurement discharge from 5 V, 10 n. F, 1/e: 500 ns 20 d. B cal. coil approximation R. Louwerse measured D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 3
Current in calibration loop current LNE 00: 18. 5 m. A LNE 50: 18. 7 m. A D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 4
LF Ring head amplifiers only output 1 output 2 Signal generator 5 Vpp, but loaded with 2 x 50 Ohm (T to scope); this time filter used at output of generator High gain mode, 148 m. Vpp not connected inside copper enclosure or defective D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 5
LF Ring head amplifiers only output 1 (low gain mode) output 1 (high gain mode) Signal generator 5 Vpp, but loaded with 2 x 50 Ohm (T to scope); Ratio: High gain / Low gain: 148 / 29. 8 = 4. 97 D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 6
HF Ring head amplifiers only output 1 Low gain mode, 27 m. Vpp High gain mode, 134 m. Vpp Ratio High gain / low gain: 4. 96 D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 7
HF Ring head amplifiers only output 2 Low gain mode, 26. 8 m. Vpp High gain mode, 134 m. Vpp Ratio High gain / low gain: 4. 96 D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 8
Calibration enable signal on ring PUs • V 2 of ring buffer amplifier • Erratic controls on I 2 C bus fixed (pull-up resistors changed, filters removed) • +12 V power regulator circuit not working correctly (resistor changed to draw needed minimum current) • Propagate these changes to the extraction line buffer amplifiers? • LF head amplifier calibration enable: • remote control working • local control working (this is different from the extraction crates) • This difference is in the design of the LNE and LNR buffer electronics in the crate • HF head amplifier calibration enable: • stuck in the enable position • this must be due to a fault either in the head amplifier or the filter box in the ring or in the cabling D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 9
Cross-calibration set-up ring / LNE 50 • one of the attenuators (30 d. B) used in the set-up for the calibration was found to be faulty with some internal bad contact that changed its value when touched • After this was replaced the cross calibration between ring LF PU and extraction LF PU could be made • For this cross calibration the LF ring PU signal was connected to the LNE 00 extraction buffer amplifier crate • Beam was extracted to the LNE 50 line and calibration measurements done with the ring PU on the last turn and then with the LNE 50 PU in the line ~36 d. B when faulty D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 10
Results of cross calibration 2. 12. 20 ring LNE 50 ring Ring head amplifier gain is higher than LNE 50 head amplifier gain (148/131 = 1. 13); this can explain difference here, but need to check equality of attenuators used LNE 50 • ring BPM • • ring beam signal has lower peak but sampling sufficient for this extra short bunch? data saved, can be checked D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 11
TRIC system 2. 12. 20 - ring ~1480/1210 = 1. 22 D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 12
TRIC system 2. 12. 20 - extraction 1410/1030 = 1. 36 D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 13
Where to go from here (07. 12. 20) • Repeat calibration measurement on LNE 00 after head amplifier change • to exclude temperature effect, need to switch it off for 1 day • Adjust or repair recovered head amplifier lab set-up, long lead time • Make a calibration of the ring LPU with comparison of electrostatic BPM system done, data to be analysed; fold in exact attenuator values • Check how it is done in AD extraction line • L-pad 195 Ohm, 68 Ohm is used in lab for TF measurement • Current divider 1: 1000 in operation with TRIC card • When was last calibration documented and by who? • need timing, RF trains • Current divider scheme possible for ELENA, but needs to be very close to • use a filter at the output of the TRIC card; precise 1: 10’ 000 divider • Software to be defined, also for the delay switching for the combined signal of LF and HF ring pick-up; calculate delay required between LF and HF PU • Spare extraction line crate being assembled; configure this crate with a linear power supply if possible to show full improvement of S/N with mitigations implemented so far • Ring PU LF, output 2 not working (head amplifier) follow-up D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 14
Back-up from previous presentation D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 15
Equivalent circuit (with attenuators) missing cable from BI racks • • 60 d. B low pass 6. 6 MHz attenuators represented as T-network low-pass filter 6. 6 MHz, 3 rd order Impedance of coil with FB amplifier from measurement discharge from 5 V, 10 n. F, 1/e: 500 ns 20 d. B cal. coil approximation R. Louwerse measured D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 16
Current in calibration loop current LNE 00: 18. 5 m. A LNE 50: 18. 7 m. A D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 17
Measurements with beam LNE 50 calibration pulse peak: 2800 (digital value in application) 18. 7 m. A assuming exponential decay: t=500 ns Qcal = 18. 7 m. A x 500 ns = 9. 35 x 10 -12 As Beam area: 0. 5*700*600 steps*ns = 210’ 000 steps*ns cal. pulse area: 2800*500 steps*ns = 1’ 400’ 000 steps*ns Qbeam=210/1400*9. 35 x 10 -12 As = 1. 40 x 10 -12 As 8. 75 x 106 charges New measurement required for LNE 00 after head amplifier change on 18. 11. 20 D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 18
Remote control of gain (LNE 00) low gain high gain D. Gamba ratio of gains: ~4. 8 D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 19
Remote control of gain (LNE 50) low gain high gain D. Gamba ratio of gains: ~5. 4 gain of LNE 00 PU about 2. 5 times less than LNE 50 PU follow-up: check transfer function and pre-amplifier in ring (Wednesday 18. 11. 20) D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 20
Surface crates LNE 00 and LNE 50 LNE 00 crate LNE 50 crate Signal generator 100 m. Vpp, but loaded with 2 x 50 Ohm (T to scope) Gain of 2. 02 D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 21
LNE 00 PU: head amplifier only High gain Low gain Generator at 5 V, but due to 2 x 50 Ohm: 3. 33 V attenuators and filter in place; but buffer amplifier not used High gain / low gain ratio = 5. 0 49. 2 m. V / 9. 7 m. V 18. 11. 20 D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 22
LNE 50 PU: head amplifiers only High gain Low gain Generator at 5 V, but due to 2 x 50 Ohm: 3. 33 V High gain / low gain ratio = 5. 0 (130 m. V / 26 m. V) 18. 11. 20 D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 23
LNE 00 PU: new head amplifiers only not warmed up High gain Low gain Generator at 5 V, but due to 2 x 50 Ohm: 3. 33 V High gain / low gain ratio = 4. 7 (71. 2 m. V / 15 m. V) ~factor 1. 5 increase in gain from old LNA, but more noisy 18. 11. 20 D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 24
LNE 00: new head amplifiers only after warming up High gain Low Gain Signal generator 5 Vpp, but loaded with 2 x 50 Ohm (T to scope) Gain High/Low: 134 m. V / 26. 6 m. V = 5. 0 Input 1 20. 11. 20 D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 25
LNE 50: head amplifiers only High gain Low Gain Signal generator 5 Vpp, but loaded with 2 x 50 Ohm (T to scope) Gain High/Low: 131 m. V / 26. 2 m. V = 5. 0 Input 1 20. 11. 20 D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 26
LNE 00 and LNE 50 on OASIS LNE 50 LNE 00 D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 27
LNE 00 and LNE 50 on TRIC LNE 00 LNE 50 Time domain response different, but gains are equal now Plan to fix recovered head amplifier and attempt to adjust it to be similar to LNE 50 D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 28
Ring pick-ups D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 29
LF Ring PU: head amplifiers only High gain Low gain Generator at 5 V, but due to 2 x 50 Ohm: 3. 33 V High gain / low gain ratio = 4. 7 140 m. V / 29. 6 m. V D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 30
HF Ring PU: head amplifiers only High gain Low gain Generator at 5 V, but due to 2 x 50 Ohm: 3. 33 V High gain / low gain ratio = 4. 7 D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 31
LNR crate LNR HF through Gain ~1/4 LNR LF through Gain ~1/9 Signal generator 100 m. Vpp, but loaded with 2 x 50 Ohm (T to scope) Looks strange, low gain and distortion, will need to repair this spare V 2 of this board available, to be checked in lab (recover front panel) D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 32
LNR crate + distribution amplifier LNR HF through Gain ~1/4 LNR LF through Gain ~1/9 Signal generator 100 m. Vpp, but loaded with 2 x 50 Ohm (T to scope) distribution amplifier has gain of 1 D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 33
LNR crate: combined output LNR HF in, combined out Gain ~1/7. 5 LNR LF in, combined out Gain ~1/7. 5 Signal generator 100 m. Vpp, but loaded with 2 x 50 Ohm (T to scope) D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 34
Spare Slides D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 35
Calibration coil delay of connection • • aligning between LNE 00 and LNE 50 PU the low frequency phase of S 11: 5 ns delay difference absolute length not known • estimated D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 36
No Filter and current divider at coil 1: 10’ 000 D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 37
No Filter and current divider / cable D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 38
Filter, current divider, no cable D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 39
Current divider with capacitor D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 40
Measurements with beam LNE 00 calibration pulse peak: 2800 (digital value in application) 18. 5 m. A assuming exponential decay: t = 500 ns Qcal = 18. 5 m. A x 500 ns = 9. 25 x 10 -12 As Head amplifier Beam area: 0. 5*180*600 steps*ns = 54’ 000 steps*ns with gain issue cal. pulse area: 1100*500 steps*ns = 550’ 000 steps*ns Qbeam=54/550*9. 25 x 10 -12 As = 0. 91 x 10 -12 As 1. 602 x 10 -19 5. 67 x 106 charges D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 41
Cables, to and from platform LNE 00 cables LNE 50 cables Signal generator 5 Vpp, but loaded with 2 x 50 Ohm (T to scope) Cables including 40 d. B att. and low-pass filter, connected in tunnel. No perceivable attenuation beyond 40 d. B D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 42
Attenuators LNE 00, 2 x 30 d. B Attenuation factor ~1200 LNE 50 60 d. B Attenuation factor ~1100 Signal generator 5 Vpp, but loaded with 2 x 50 Ohm (T to scope) D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 43
LNE 00: head amplifiers only (warm) High gain Low Gain Signal generator 5 Vpp, but loaded with 2 x 50 Ohm (T to scope) Gain High/Low: 134 m. V / 26. 6 m. V = 5. 0 Input 1 D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 44
LNE 00: head amplifiers only (warm) High gain Low Gain Signal generator 5 Vpp, but loaded with 2 x 50 Ohm (T to scope) Gain High/Low: 134 m. V / 26. 6 m. V = 5. 0 Input 2 D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 45
LNE 50: head amplifiers only (warm) High gain Low Gain Signal generator 5 Vpp, but loaded with 2 x 50 Ohm (T to scope) Gain High/Low: 131 m. V / 26. 2 m. V = 5. 0 Input 1 20. 11. 20 D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 46
LNE 50: head amplifiers only (warm) High gain Low Gain Signal generator 5 Vpp, but loaded with 2 x 50 Ohm (T to scope) Gain High/Low: 130 m. V / 26. 2 m. V = 5. 0 Input 2 D. Gamba, W. Hofle, R. Louwerse, V. Myklebust update 07. 12. 2020 47
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