1 What I’ve been doing for many of the days you haven’t seen me here Bill Ashmanskas Nov 25, 2003

2 First things first … a shameless plug PR D physics/ But since August, when this stuff was finished, I’ve joined Bill Foster’s ongoing damper board effort for Run II

3 Bill Foster’s damper board team includes Bill Foster Dave Wildman Dennis Nicklaus Alexei Seminov Warren Shappert Sten Hansen Terry Kiper Bill Ashmanskas Eric James FNAL/BD PPD engineering ANL/CDF FNAL/CDF

4 Outline What is a “damper” anyway? What does this damper look like? How have I been able to help out so far?

5 What does a damper do?  Detect coherent bunch oscillation w.r.t. stable orbit and apply a kick to correct it  Correct for injection errors (x,x’,y,y’, ,E) before beam filaments (emittance growth)  Counteract instabilities before they grow out of control  Do this for horizontal, vertical, and longitudinal coordinates

6 Transverse motion w.r.t. stable orbit (cartoon)

7 Many particles, with their own small excursions

8 Steering error  bunch centroid oscillates

9 If coherent motion isn’t corrected, nonlinearities cause beam to decohere, fill larger phase space

10 Transverse damper at work (GWF, Lehman review)

11 Transverse damper at work (GWF, Lehman review)

12 Transverse damper at work (GWF, Lehman review)

13 Transverse damper at work (GWF, Lehman review)

14 Transverse damper at work (GWF, Lehman review)

15  You can see that damper project has merit  The longitudinal damping is now under test, and should yield results that are more impressive  Results I showed are from before I joined (except that I helped with the late-2002 prototyping)  Key point: This is work to which CDF electronics types can readily contribute (familiar hardware)  I’ve been helping Bill F to commission the second-generation damper boards, which arrived in July 2003

16 Bill Foster’s damper concept (or VME, VXI, PCI, etc.)

17 What the FPGA computes

18 Relevance of CDF experience: this isn’t so scary... once you’re used to working with this

19 Prototype damper (kludged commercial board)

20 New board being commissioned

21 In-house damper board, by A. Seminov  One Altera Stratix 1S30 (vs 5 separate older Altera chips on commercial board)   much more straightforward to program  212 MHz ADCs (vs interleaved 106 MHz pairs)  424 MHz DACs (vs 212 MHz on daughter card)  On-board CPU+ethernet for configuration and ACNET interface (vs VME + JTAG cable)

22 So far, I’ve been mainly working on the configuration & readout path for the new board (because Alexei is stuck in Russia!). Good progress: e.g. can configure stand-alone board via TCP/IP, have established communication with Dennis Nicklaus’s ACNET interface. Meanwhile, Eric (the other CDF guy) and Warren are showing that this board could work for Tevatron BPM readout.

23 Same board can do BPM readout!

24 Summary  Once I got my CDF papers out, I decided that the most useful thing I could do was to try to help Bill F with his damper board  People with HEP trigger/DAQ experience should not have much trouble finding a way to contribute  The same programmable-chip technology that has had a big impact on the CDF trigger can be readily applied to all sorts of beam measurement/feedback/control