Tevatron Ionization Profile Monitors - design, results & status Andreas Jansson K.Bowie, T.Fitzpatrick, R.Kwarciany, C.Lundberg, D.Slimmer, L.Valerio, J.Zagel Also thanks to: T.Anderson, M.Bowden, A.Bross, A. Chen, R.Dysert, S.McCormick, S. Suleimani, H.Nguyen, C.Rivetta, H.Glass, D.Harding, B.Hively, V. Kashikin, D.Miller, Z.Tang, J.Volk, T.Zimmermann, …

9/21/07IPM Review, September 21, 2007 A. Jansson 2 Talk Outline Intro Design and Implementation Measurement Results Future measurement plans Issues encountered and fixed Remaining issues Summary

9/21/07IPM Review, September 21, 2007 A. Jansson 3 Goal GOAL: Measure protons and pbar beam size turn by turn at injection and ramp during normal operation to diagnose and mitigate emittance blow-up.

DESIGN AND IMPLEMENTATION 9/21/07IPM Review, September 21, 2007 A. Jansson 4

9/21/07IPM Review, September 21, 2007 A. Jansson 5 Challenges in the Tevatron Two small beams separated by helix. Separate protons from pbars, injected from circulating beam Beam induced parasitic signals. Low vacuum pressure Fine granularity and many channels Single bunch resolution and gating Improved shielding and matched cables Local pressure bump with controlled leak Solutions: Challenge:

9/21/07IPM Review, September 21, 2007 A. Jansson 6 IPM detector 0.2T MCP 1kV 100V 0V 9.9kV 10kV All signal cables are enclosed in a Faraday cage!

9/21/07IPM Review, September 21, 2007 A. Jansson 7 Anode board and internal cabling ¼ mm strip pitch 200 channels (128 instrumented) Board mounted series resistor for back- termination and LP filtering. In-vacuum signal cabling using UHV-compatible flex-circuits High resolution area can be moved by swapping connectors

Front end cabling 40 channels in each vacuum DB50 feed- thru (flex circuit) Transition board from feed-thru. Mini-coax bundles with external shield. Custom (CMS) DB coax connector in FE board. 9/21/07IPM Review, September 21, 2007 A. Jansson 8

9/21/07IPM Review, September 21, 2007 A. Jansson 9 Microchannel plate Max gain with 36 proton bunches is ~1e4 to avoid saturation. Can be achieved with single plate With dual plates, each plate would run at a very low gain and low bias current. Use single MCP with extra-high bias current.

9/21/07IPM Review, September 21, 2007 A. Jansson 10 Microchannel plate saturation MCP output current per unit area is limited by MCP pore recharge time. If hit rate per pore exceeds recharge time, output is reduced Onset of saturation observed in MI IPMs, as expected from calculations.  For Tev, will abandon Chevron configuration since extra gain can not be utilized (allows to run at higher bias). Turn # measurement: L. Short Bull

9/21/07IPM Review, September 21, 2007 A. Jansson 11 DAQ system CMS-QIE chip digitizes signal in tunnel. Serial data uplink on optical fiber. Receiver and data buffer in upstairs PC Timing + QIE clock + QIE clock supplied from PC thru cat-5E cable Timing card (PCI) Timing fanout QIE cards (16x 8 ch) Data Buffer (2x 8 links) (PCI) Host PC (LabView) Service building Tunnel

9/21/07IPM Review, September 21, 2007 A. Jansson 12 Fermilab QIE8 ASIC Charge Integrating Encoder (QIE) developed at Fermilab. Used by KTeV, CDF, Minos, CMS… Frequency range 7-53 MHz Essentially no deadtime. LSB 2.6fC (16000e) in logarithmic mode, 0.9fC (6000e) in linear mode Dynamic range >10 4 in logarithmic mode Noise of O(1fC) Radiation “tolerant” design: T. Zimmerman

9/21/07IPM Review, September 21, 2007 A. Jansson 13 QIE card 8 channels (CMS QIE8) per board. Achieved noise ~1.8fC with 4’ cable. Data is combined with timing information, serialized by CERN GOL ASIC (rad hard) and sent thru optical fiber at 1.1Gbps data rate Timing fanout board cleans up and distributes clock and timing signals

FE board input/output format 9/21/07IPM Review, September 21, 2007 A. Jansson QIE QIE1QIE2QIE3 QIE5QIE6QIE7 QIE4 CAPID0 Timing bits TX_EN/RX_DV QIE0QIE1QIE2QIE3 QIE5QIE6QIE7 QIE4 CAPID1 Timing bits QIE0QIE1QIE2QIE3 QIE5QIE6QIE7 QIE4 CAPID2 Timing bits Proton Revolution CounterError bits QIE mode 2RF/7 Clock Counter 11000No effect 11001Proton Injection Marker 11010Antiproton Injection Marker 11011QIE Mode0 (QIE in Calibration Mode) 11100QIE Mode1 (QIE in Mode) 11101QIE Mode2 (Link test - outputs a 32-bit counter to GOL) 11110QIE Mode3 (Reset QIEs) 11111Board Reset 15MHz clock frequency Proton and pbar revolution markers Encoded signal: INPUT (Cat5 cable) OUTPUT (1.6Gbps serial link)

9/21/07IPM Review, September 21, 2007 A. Jansson 15 Data buffer card Handles 8 incoming optical links (64 channels, 1.1 GB/s of data) Can sparsify data on–the- fly based on timing masks 512MB RAM allows for – turns of continuous data – turns for 72 bunches –6 million turns for a single bunch Read out thru PCI64 bus. Two boards are used to handle 128 channels. Sync via jumper cable IPM buffer board doubled as prototype for BTeV L1 data buffer. Considered for use in MICE experiment.

Buffer memory formats 9/21/07IPM Review, September 21, 2007 A. Jansson 16

9/21/07IPM Review, September 21, 2007 A. Jansson 17 Timing card Produces the 15MHz (2/7 RF) QIE clock Decodes and transmits beamsync revolution marker + injection and trigger events Controls QIE settings. 396 ns (21 buckets) p-pbar separation ~120ns RF 2/7

Timing fanout card Timing fanout board cleans up and distributes clock and timing signals to the front end boards. 9/21/07IPM Review, September 21, 2007 A. Jansson 18

9/21/07IPM Review, September 21, 2007 A. Jansson 19 Software Both IPMs now have new software and firmware. Software/Firmware still being improved. Vertical IPM works pretty well. Horizontal IPM has some hardware problems (one dead FE board, one FE board with a sync problem, several broken channels) that require an access. NB. REAL DATA!

9/21/07IPM Review, September 21, 2007 A. Jansson 20 Tev IPMs now hooked up to ACNET Magnets –T:IPMH –T:IPMV Sweep Voltage –T:HPMCF –T:VPMCF MCP Voltage –T:HPMCP –T:VPMCP Control register –T:HPMCMD –T:VPMCMD Active PSpec –T:HPMAS –T:VPMAS Acquisition # –T:HPMTT –T:VPMTT Page T53

9/21/07IPM Review, September 21, 2007 A. Jansson 21 Output ACNET arrays T:HPMP01 T:VPMP01 T:HPMS01 T:VPMS01 T:xPMynn, x=H/V, y=P/S/C/B/E, nn=01-72 Position/Size (Sigma)/Charge/Baseline/Error (Chi-squared)

9/21/07IPM Review, September 21, 2007 A. Jansson 22 Tunnel installation Detector goes here! Magnets, stands, vacuum chambers, pumps, cables, plumbing put in place during shutdown autumn 2004

9/21/07IPM Review, September 21, 2007 A. Jansson 23 Vertical detector installation shutdown moved to 2006 Took advantage of magnet failure to install the vertical detector in Dec ‘05. Test DAQ system with 40 channels, 1cm active width, single buffer board E0 service building E0 straight section

9/21/07IPM Review, September 21, 2007 A. Jansson 24 Detector (re)installation shutdown: Vertical detector arcing and vacuum problem fixed. Horizontal detector installed. Both fitted with 40 channel reduced readout system

9/21/07IPM Review, September 21, 2007 A. Jansson 25 Beam size at IPM location By moving detector, able to fit beam in active area, except horizontal beam size at 150GeV

MEASUREMENT RESULTS 9/21/07IPM Review, September 21, 2007 A. Jansson 26

9/21/07IPM Review, September 21, 2007 A. Jansson 27 Very first beam results First data taken at 980GeV during store 4634 without magnetic field. 1cm one turn

9/21/07IPM Review, September 21, 2007 A. Jansson 28 Effect of reduced field Sparking problems prevented running at full fields (25% B, 70% E). Profile widening due to large Larmor radius of electrons Measured resolution at 50A is 0.5 mm

9/21/07IPM Review, September 21, 2007 A. Jansson 29 Protons during store Measured profile widths at 980: mm consistent with flying wires taking into account the low B-field Store #4641 Magnet at 50A (nominal 200A) Single turn profiles for 36 proton bunches!

9/21/07IPM Review, September 21, 2007 A. Jansson 30 Hint of pbars during store NOTE: Detector centered on proton orbit Store #4641 Magnet at 50A (nominal 200A)

9/21/07IPM Review, September 21, 2007 A. Jansson 31 Proton during injection Proton profiles 16 turns before injecting P36 Store #4642 Magnet at 50A Single turn profiles for 36 bunches!

9/21/07IPM Review, September 21, 2007 A. Jansson 32 Protons at injection Raw profile width Bunch #36 turn-by-turn 1 cm Store #4642Magnet at 50A Corrected for low B-field 0 35 turns

9/21/07IPM Review, September 21, 2007 A. Jansson shutdown work Vertical detector removed to fix vacuum and sparking problems. Reinstalled. Horizontal detector installed. Both systems initially instrumented with 40 out of 128 channels (1cm active width).

9/21/07IPM Review, September 21, 2007 A. Jansson 34 First profiles after shutdown Proton bunch #22 at 150GeV during store #4772. Measured beam size 1.05mm, turn-by-turn variation ~50um. Total signal per bunch ~1.7pC. 1 cm 30 turn average single turn Single bunch proton profiles Magnet at 200A

9/21/07IPM Review, September 21, 2007 A. Jansson 35 Protons at low beta Proton bunch #1 at low beta during store #4758. Measured beam size 0.55mm, turn- by-turn variation (noise) 20µm. Total signal per bunch ~1.3pC. 30 turn average single turn Magnet at 200A

9/21/07IPM Review, September 21, 2007 A. Jansson 36 Injection – Full B field Proton bunch #21 turn-by-turn 1 cm Store #4772Magnet at 200A RMS profile width [mm] FFT 0 35 turns

9/21/07IPM Review, September 21, 2007 A. Jansson 37 Effect of magnetic field strenght Measured beam size and total signal as a function of magnet current. Resolution due to Larmor radius ~0.1mm at 200A (2% effect for a 0.5mm beam). Signal increase with B- field may be due to detection efficiency (threshold is >1 primary electron per channel).

9/21/07IPM Review, September 21, 2007 A. Jansson 38 Effect of drift field strength Measured beam size and total signal as a function of drift field (voltage). Negligible effect on profile width. Maximum signal at ~7kV drift voltage (MCP sensitivity peaks at ~3keV for electrons)

9/21/07IPM Review, September 21, 2007 A. Jansson 39 Effect of alignment Measured beam size and total signal as a function of tilt angle. No observable effect within a few mrads.

9/21/07IPM Review, September 21, 2007 A. Jansson 40 Flying wire comparison Known electronics problem (cross talk from revolution marker pulse) Comparison of vertical beam size from IPM and nearby Flying Wire. Tuning of abort gap cleaner timing had caused blow-up of certain bunches. From MAD lattice file, expect a 13% wider beam at Flying Wire. See ~1%.

9/21/07IPM Review, September 21, 2007 A. Jansson turns Four injection measurements superimposed

9/21/07IPM Review, September 21, 2007 A. Jansson turns FFT of: First 100 turns Turn

9/21/07IPM Review, September 21, 2007 A. Jansson 43 P150 transfer line Plot from M. Berdnikov

9/21/07IPM Review, September 21, 2007 A. Jansson 44 Transfer tuning study September 20 th : changed selected x-fer line quads Nominal settings Q701 at -22A Q701 at -42A Q711 at -25A NB. Q711 was found to steer the beam significantly

9/21/07IPM Review, September 21, 2007 A. Jansson 45 Measured mismatch vectors Nominal settings Q701 at -22A Q701 at -42A Q711 at -25A Need to increase Q711 by ~15A (saturation?) Should result in 5-10% smaller vertical emittance Should have very little effect on horizontal plane. Should have been tested this morning…

9/21/07IPM Review, September 21, 2007 A. Jansson 46 Effect of Q711 Nominal settings Q701 at +10A Q701 at +20A Nominal settings Q701 at -25A

Outcome of matching tests… 9/21/07IPM Review, September 21, 2007 A. Jansson 47 Installing corrections appear to have made vertical worse, horizontal slightly better But, there was coupling correction done at ~ same time. Emittance blow-up

9/21/07IPM Review, September 21, 2007 A. Jansson 48 Pbars at 980 Gev Store #5172 HorizontalVertical …moved the detector towards pbar orbit, and voila, I also see it in vertical plane!

9/21/07IPM Review, September 21, 2007 A. Jansson 49 Pbars at 150 GeV Also saw coasting pbars (with vertical system) at injection Requires moving the detector to pbar orbit. Triggering did not work at first attempt (timing event found to be disabled). Fri Jan , shot #5175

9/21/07IPM Review, September 21, 2007 A. Jansson 50 Shot 5186 – vertical plane Two consecutive beam revolutions in Tevatron, just at injection of batch 9.

9/21/07IPM Review, September 21, 2007 A. Jansson 51 Vertical injection data (batch 9) Beam position gives consistent oscillation ~0.2mm. Need to look closer at beam size data, but… There is a clear frequency component at twice the tune! Beam size [mm] Beam position [mm] 100 0

Reverse protons in MI 9/21/07IPM Review, September 21, 2007 A. Jansson 52 June 11, 2007 Perhaps a hint of horizontal mismatch? horizontal vertical

9/21/07IPM Review, September 21, 2007 A. Jansson 53 Summary The Tevatron IPMs can measure single proton bunches turn-by-turn both at injection and top energy. Observed sensitivity of ~20µm at 980GeV, 50-60µm at 150GeV. Good relative agreement with Flying Wires for coasting beam. Significant vertical beam size oscillation observed at injection, correction attempted. Have measured pbars as well, although with less sensitivity.

Future plans Do full mismatch measurement, attempting to correct both planes. Measure how local coupling affecting measurement. (Re)measure the dispersion mismatch component. 9/21/07IPM Review, September 21, 2007 A. Jansson 54

ISSUES IDENTIFIED AND FIXED 9/21/07IPM Review, September 21, 2007 A. Jansson 55

9/21/07IPM Review, September 21, 2007 A. Jansson 56 Vacuum problems Poor initial vacuum traced to retro-fitted torlon flex retainer pieces. Surface area of torlon increased by x4 from pre-installation tests, but vacuum worse by x100 Contaminated un- machined surfaces? Made new parts out of teflon-glass

9/21/07IPM Review, September 21, 2007 A. Jansson 57 HV filters Bench tests showed sharp resonances related to the (electrically isolated) high voltage plate. Use filters on HV cables to damp high frequency signals

9/21/07IPM Review, September 21, 2007 A. Jansson 58 Arcing problem… Kapton coated HV wire was slightly magnetic, and had some slack With magnet at sufficiently high strength, wire was bent and arcing occurred Shortened the wire and added kapton spacers to fix problem

9/21/07IPM Review, September 21, 2007 A. Jansson 59 MCP and Vacuum A slight vacuum pressure increase was seen with the MCP on at 980V

9/21/07IPM Review, September 21, 2007 A. Jansson 60 Signal/Grounding issues Initially, inadequate grounding caused the distributed clock to get into the front end analog signal. Problem reproduced upstairs and fixed during short tunnel access.

9/21/07IPM Review, September 21, 2007 A. Jansson 61 Parasitic signals Despite very good shielding, beam related signals still present with MCP gain off. Very stable from turn to turn -> reference subtraction possible Present even on “broken” channels (where no ionization electrons are seen) 1x1 store at 980GeV ~center anode strip Timing markers Beam pulse

9/21/07IPM Review, September 21, 2007 A. Jansson 62 Timing pulse crosstalk Revolution timing pulse generating signal on QIE input. Solve by adding bypass capacitors on the timing fanout card and backplane

9/21/07IPM Review, September 21, 2007 A. Jansson 63 Slow DAQ debugging QIE front end card Timing card Data Buffer Card Some functionality could only be tested using the buffer card. Crowded FPGA on buffer card slowed turn-around time for debugging. Antifuse FPGA on front end -> hold off production until fully debugged.

PCI card poll glitching SERDES Polling card via PCI during measurement was found to glitch the SERDES reciever. “Solved” by using interrupt instead of polling, and reorganising code to minimize PCI traffic during acquisition. 9/21/07IPM Review, September 21, 2007 A. Jansson 64

Front end card spontaneous resets Occasionally, front end cards reset spontaneously –Radiation induced? Comes back up out of sync, in calibration mode. Effect limited by minimizing time between arm and trigger. 9/21/07IPM Review, September 21, 2007 A. Jansson 65

DAQ firmware bugs fixed Memory format and access Buffer board synchronisation Front end board synchronization Internal error checking and error bits … 9/21/07IPM Review, September 21, 2007 A. Jansson 66

STATUS & REMAINING ISSUES 9/21/07IPM Review, September 21, 2007 A. Jansson 67

Status New larger N2 leak installed this shutdown (now we have two). Expect to come out of shutdown with ~10 final version boards in both systems. Both systems will have 2 buffer boards Repaired and upgraded FE power supply will be able to handle 20 boards. 9/21/07IPM Review, September 21, 2007 A. Jansson 68

FE Power Supply Current power supply has overheating problem. –Need bigger heatsinks, but won’t fit without new board layout. –Temporary solution uses 4 boards instead of 2, but not optimal for airflow. Building new supply capable of handling two full crates of boards without overheating issues. 9/21/07IPM Review, September 21, 2007 A. Jansson 69

Front-end boards No know hardware/firmware bugs Need to build spares –32 built originally (28 working, 5 of which still have old firmware) –100% percent spares was planned initially, due to uncertainty about radiation environment, but no boards lost as of yet. May reconsider number. 9/21/07IPM Review, September 21, 2007 A. Jansson 70

Buffer board No know hardware/firmware bugs. Firmware update to arm slave board thru jumper cable –Avoid unsynchronized acquisition if a trigger is received when only one board has been armed. NB. Some firmware features have not been tested yet. 9/21/07IPM Review, September 21, 2007 A. Jansson 71

Software Need to figure out how to best make sequencer-driven acquisitions –Currently, the system is armed (HV turned on) by pushing a LabView button or setting an ACNET parameter, then triggered by a timing event. –May want to arm on timing event. 9/21/07IPM Review, September 21, 2007 A. Jansson 72

Summary IPMs have produced useful results. More measurements will be possible with fully functional horizontal detector Vertical system came up without much problems, horizontal more complicated due to lower signals are more channels (ie requiring dual buffer boards). Expect to come out of shutdown with close-to-final configuration. 9/21/07IPM Review, September 21, 2007 A. Jansson 73