1. TEVATRON IONIZATION PROFILE MONITOR Andreas Jansson Fermilab

2. 11/11/2004Tevatron Ionization Profile MonitorA. Jansson 2 People AD: C. Rivetta L. Valerio J. Zagel B. Dysert … CD: M. Bowden R. Kwarciany PD: A.Bross K. Bowie H. Nguyen T. Fitzpatrick … Also help from: D. Harding (TD), V. Kashikin (TD), T. Zimmerman (PD), Z. Tang (PD) and the Tev Techs

3. 11/11/2004Tevatron Ionization Profile MonitorA. Jansson 3 Talk outline Motivation for IPMs Challenges in Tevatron Design of Tevatron IPMs Tests Pictures from the tunnel

4. 11/11/2004Tevatron Ionization Profile MonitorA. Jansson 4 Motivation

5. 11/11/2004Tevatron Ionization Profile MonitorA. Jansson 5 IPM working principle Measure distribution of rest gas ionization by: –Drifting ions onto a detector using an electric field, or –Drifting ionization electrons onto a detector using a E||B field. Beam - B - E -

6. 11/11/2004Tevatron Ionization Profile MonitorA. Jansson 6 Challenge I – Small beam size Small beam size Low gas pressure

7. 11/11/2004Tevatron Ionization Profile MonitorA. Jansson 7 Challenge II – Beam separation  = 20  mm mrad  p/p = 7.5 10 -4 X [mm] Y [mm] Inj. old helix Inj. new helix Flattop One and three sigma contours

8. 11/11/2004Tevatron Ionization Profile MonitorA. Jansson 8 Challenge III – Residual gas pressure Gas pressure at E0 before 2004 shutdown was in low 10 -8 ’s, slated to be improved Based on estimated gas composition, expect about 1000e/bunch for a ¼ mm  10 cm detector at 3 10 8 torr and 2.7 10 11 protons/bunch. Need for a local vacuum bump after vacuum inprovements.

9. 11/11/2004Tevatron Ionization Profile MonitorA. Jansson 9 Challenge IV – Parasitic signals

10. 11/11/2004Tevatron Ionization Profile MonitorA. Jansson 10 Simulations Injection is most difficult (fewer counts per channel). Signal per bunch is small, but gain limited by MCP saturation effects from total (proton) signal. Need about 300 primaries (per bunch) for 10% beam width accuracy (requires gas injection). Higher accuracy can be obtained by averaging many turns (ramp measurement).

11. 11/11/2004Tevatron Ionization Profile MonitorA. Jansson 11 Fermilab QIE8 ASIC Charge Integrating Encoder (QIE) Developed at Fermilab Used by KTeV, CDF, Minos, CMS… Frequency range 7-53 MHz No deadtime. LSB 2.6fC in logarithmic mode, 0.9fC in linear mode Dynamic range >10 4 in logarithmic mode Can achieve noise of O(1fC)

12. 11/11/2004Tevatron Ionization Profile MonitorA. Jansson 12 MCP test stand

13. 11/11/2004Tevatron Ionization Profile MonitorA. Jansson 13 MCP saturation MCP output current per unit area is limited by MCP pore recharge time. Onset of saturation observed in MI IPMs, as expected from calculations.  Will abandon Chevron configuration since extra gain can not be utilized (allows to run at higher bias). Measured emittance vs MCP voltage in MI IPM at different points in the acceleration cycle Turn #

14. 11/11/2004Tevatron Ionization Profile MonitorA. Jansson 14 QIE test stand Using laser based PMT test setup in Lab6 KTeV test board modified with CMS- QIE Observed good linearity and insensitivity to clock phase

15. 11/11/2004Tevatron Ionization Profile MonitorA. Jansson 15 Tracking – transverse displacement B=0.2 T, E=100kV/m

16. 11/11/2004Tevatron Ionization Profile MonitorA. Jansson 16 Cable tests Stepping QIE clock phase w.r.t the incoming pulse, can improve time resolution Derivation of composite signal yields the original pulse Used to study reflections due to connectors in front-end cabling

17. 11/11/2004Tevatron Ionization Profile MonitorA. Jansson 17 Rad level measurements Reading 125 mrad/h during normal running at ~4.5 feet 18 years to 20 krad!

18. 11/11/2004Tevatron Ionization Profile MonitorA. Jansson 18 Component rad tests Tested commercial TI serializer in Tevatron tunnel for >200 days. Previously tested (by others) for total dose ~Mrad. Only handful of link errors seen. One latchup candidate, cleared by cycling power. Observed error rate should not affect operation.

19. 11/11/2004Tevatron Ionization Profile MonitorA. Jansson 19 Detector design Based on MI eIPM prototype –Flange-mounted detector for quick installation Many modifications –Better screening –Provisions for calibration device

20. 11/11/2004Tevatron Ionization Profile MonitorA. Jansson 20 Anode board

21. 11/11/2004Tevatron Ionization Profile MonitorA. Jansson 21 Magnets Single corrector for simplicity. Electromagnets chosen. Can be turned off to verify effect on measurement and machine. Bought from outside manufacturer.

22. 11/11/2004Tevatron Ionization Profile MonitorA. Jansson 22 Field quality E-field is not perfect longitudinally E×B component produces a small transverse drift velocity To first order, this generates a rotation of the beam “image”, removed by beam-based alignment Higher order terms distort the beam image, expect order ~30 nm rms effect on beam size.

23. 11/11/2004Tevatron Ionization Profile MonitorA. Jansson 23 DAQ system CMS-QIE front end in tunnel. Serial data uplink on optical fiber Receiver and data buffer in upstairs PC Timing + clock + QIE settings supplied from PC thru cat-5E cable Timing card (PCI) Timing fanout QIE cards (16x 8 ch) Data Buffer (PCI) Host PC (LabView)

24. 11/11/2004Tevatron Ionization Profile MonitorA. Jansson 24 Timing card Produces the 15MHz (2/7 RF) FE clock Decodes and transmits beamsync clock (p & pbar) injection events Transmits QIE settings Separate version of card will decode TCLK/MDAT

25. 11/11/2004Tevatron Ionization Profile MonitorA. Jansson 25 396 ns (21 buckets) p/pbar separation RF 2/7 1/7 Timing scheme

26. 11/11/2004Tevatron Ionization Profile MonitorA. Jansson 26 Front end card 8 channels (CMS QIE) per board. Data is serialized by CERN GOL ASIC (rad hard) and sent thru fiber Timing fanout board cleans up and distributes clock and timing signals timing fanout QIE card

27. 11/11/2004Tevatron Ionization Profile MonitorA. Jansson 27 Data buffer card Doubles as BTeV L1 data buffer prototype.

28. 11/11/2004Tevatron Ionization Profile MonitorA. Jansson 28 Controlled N 2 leak system Leak 1 Leak 2 Ion pump Isolation valve

29. 11/11/2004Tevatron Ionization Profile MonitorA. Jansson 29 Differential pumping scheme ion pump gauge shut-off valve sector valve sector valve leak (remote, manual or fixed) orifice ipm regulator N2N2 pipe radius reduction pipe radius reduction

30. 11/11/2004Tevatron Ionization Profile MonitorA. Jansson 30 Controlled N 2 leak tests at E4R Red traces: IP and IG in leak chamber Green, Blue and Cyan: IPs and IG in main chamber 6 hours 3 decades leak on

31. 11/11/2004Tevatron Ionization Profile MonitorA. Jansson 31 Tunnel installation

32. 11/11/2004Tevatron Ionization Profile MonitorA. Jansson 32 Conclusions and outlook