New Ideas on long-term DCT upgrade: conceptual design for DOCAZ Ted Liu (Fermilab, thliu@fnal.gov) Related material can be found: For DOCAD: see http://www.slac.stanford.edu/~thliu/trigger_oct_final.pdf http://babar-hn.slac.stanford.edu:5090/HyperNews/get/TrigOper/221.html For BLTz: see http://babar-hn.slac.stanford.edu:5090/HyperNews/get/TrigOper/245.html This talk contains some more details on what I have talked about at the end of the first upgrade meeting on July 5th. Ted Liu, July 18,00, idea on Ztrigger

Ted Liu, July 18,00, idea on Ztrigger What kind of background we are dealing with? B1 HER LER Lost particle interact with beampipe flange real collision due to a step in the synchrotron mask Track z distribution for L1 passthrough events Ted Liu, July 18,00, idea on Ztrigger

The Drift Chamber ( DCH ) L1 Long term strategy: cut in Z using TSF fine position info from stereo superlayers Cell size: 1.2 cm x 1.8 cm The Drift Chamber ( DCH ) 10 superlayers of 4 layers each Axial and stereo alternate Ted Liu, July 18,00, idea on Ztrigger

Ted Liu, July 18,00, idea on Ztrigger L1 long-term strategy: Can we cut in Z using TSF position info from stereo SLs? Stereo SLs --> Z Axial SLs --> DOCA DOCAZD Close to IP in z Cosmic ray events Off IP in z Ted Liu, July 18,00, idea on Ztrigger

Ted Liu, July 18,00, idea on Ztrigger What has been discussed in the past: Long ago, Anders Ryd and I talked about one possible hardware implementation using a large( or huge) LUT approach in r-phi view. In other words: move some L3 DCH algorithm upstream to L1. Curent L3 first stage DCH Track finding algorithm involves slicing in phi in 120 bins. Without track fitting, z resolution is rather poor. Hardly surprising as each bin size is on the order of ~ few cm even for the inner most SLs (TSF fine phi resolution ~ 1 mm). To make more slices (> x10), could involve huge LUTs … Ted Liu, July 18,00, idea on Ztrigger L3 Event Display Here is an new (simpler) idea … next

Ted Liu, July 18,00, idea on Ztrigger Use the simple fact: tracks are straight lines projected in r-z plane r-z view r-phi view Ted Liu, July 18,00, idea on Ztrigger

Ted Liu, July 18,00, idea on Ztrigger Basic idea (have many slices in theta) Off Z track 40~50 or so slices in theta ~ 2 cm in z for SL2 TSF phi resolution ~ 1 mm Z resolution ~ 2 cm Ted Liu, July 18,00, idea on Ztrigger

Ted Liu, July 18,00, idea on Ztrigger Simplest case: high Pt tracks Use Axial&Stereo SL segments fine phi to calculate z: total 6 points  slices x A10 x U9 x U8 x A7 Convert phi separation into z separation x V6 x U5 tracks from IP will leave hits in one  slice, tracks off IP in z will leave hits in many  slices x A4 Z (i) track finding algorithm: for ith  slice,  hits >= 4 (out of 6) x V3 x U2 (same idea as in DOCAD) x A1 Ted Liu, July 18,00, idea on Ztrigger programmable Could even try weighted (by resolution) sum

Ted Liu, July 18,00, idea on Ztrigger when low Pt tracks involved: need corrections (Pt dependent) for example: phi separation for A1&U2:  = 2 - 1c, not 2 - 1 A10 seed x A10 then convert  into Z A7 this is because  is wrt the pivot cell for each SL 2 A4 1c x if  is wrt the top and bottom cells, may not need corrections. but too much change in TSF? x U2 A1 1 this can be naturally done in Pt slices: i.e. in DOCAD  what is DOCAD? Ted Liu, July 18,00, idea on Ztrigger

Ted Liu, July 18,00, idea on Ztrigger Current PTD algorithm New DOCAD algorithm (baseline design: simple algo.) A10 seed x x Pt threshold (800MeV) Pt slices SL7 SL7 … … SL4 SL4 SL1 SL1 x x IP IP Tracks (above threshold) coming from IP should leave all the hits in one of the slices 4 hits on one track with ~1mm, should be able to tell whether the track is from IP Tracks not coming from IP will most likely leave hits in different slices Ted Liu, July 18,00, idea on Ztrigger for details on DOCAD, see http://www.slac.stanford.edu/~thliu/trigger_oct_final.pdf http://babar-hn.slac.stanford.edu:5090/HyperNews/get/TrigOper/221.html

Ted Liu, July 18,00, idea on Ztrigger Thus a possible DOCAZD algorithm could be: For each seed (as in current PTD): use DOCAD algorithm locate axial SL hits for each Pt slice for a given axial SL hit in a given Pt slice, look for nearby U or V SL hits in a certain range (max range&sign is SL dependent) (3) apply the correction in  to get  (4) convert  into Z (5) then in r-z plane, for each  slice, apply z track finding algorithm:  hits >= 4 (out of 6) Note: as in PTD, DOCAZD seeds can be in SL10 or SL7. if one axial SL hit is missing, the correction can still be made for each Pt slice DOCAZ requires a track coming from IP in both x-y & z view Ted Liu, July 18,00, idea on Ztrigger Each board should receive enough neighbor data to cover low Pt tracks (at least ~200 MeV)

Ted Liu, July 18,00, idea on Ztrigger Drift Chamber One possible scenario keep BLT path the same (many advantages!) All track segments found Trigger data Supercell hits 24 Gbits/s B &/or A GLT Fine phi info for all SLs DOCA&Z? DOCAD in r- plane Axial SLs  -> Z DOCAZD X 16 ? Z track finding in r-z plane Stereo SLs Ted Liu, July 18,00, idea on Ztrigger Track Segment Finder (x24)

Ted Liu, July 18,00, idea on Ztrigger Basic DOCAZ engine unit (for a given seed): 3D problem  2d problem in r-z & r-phi planes a given seed 9 x 8 x 6 x … 5 …. x in r-phi plane … 3 x 2 x project into r-z plane IP If no GLT modification: Z(i) can be ORed to give one Z for a given seed, then converted into 16 bits phi map (passed to GLT , as in A’) Or only keep B from BLT, and have DOCA and Z output to GLT. Ted Liu, July 18,00, idea on Ztrigger detailed information saved in trigger DAQ data

Ted Liu, July 18,00, idea on Ztrigger Basic DOCAZ engine unit: possible improvement (1) a given seed 9 x 8 x 6 x … 5 …. x …. in r-phi plane … 3 x 2 x IP project into r-z plane Overlapping slices in both r-z and r-phi planes (only shown in r-z plane) Ted Liu, July 18,00, idea on Ztrigger

Ted Liu, July 18,00, idea on Ztrigger Basic DOCAZ engine unit: possible improvement (2) a given seed 9 x 8 x 6 x … 5 …. x …. in r-phi plane … 3 x 2 x IP project into r-z plane finer slices in outer SLs (take advantage of the ~2cm Z resolution) outer good SL hits may provide enough constraint in z Ted Liu, July 18,00, idea on Ztrigger Prefer configurable for robustness

Ted Liu, July 18,00, idea on Ztrigger This is just a conceptual design Probably a good starting point, but needs lots of studies: How many slices in r-z and r-phi planes? What’s the lower limit in Pt? Can we go below 200 MeV? (limited by hardware?) (3) Impact on physics? (tau & 2-photon) Very high multiplicity B decays will likely only have low Pt tracks, define >= 4 A&B trigger line to save these events, no requirement on DOCAZ? How much can be save this way? How much bkg? (4) how much background can be rejected? (5) Performance vs Chamber cell ineff.? Robustness? (6) Performance vs high background (occupancy)? (7) Hardware implementation details… The devil is in the details. But most of them (if not all) can be studied with existing TSF data! Well defined problems… Ted Liu, July 18,00, idea on Ztrigger CAREFUL calibration of TSF LUTs is very important!

Ted Liu, July 18,00, idea on Ztrigger L1 long-term strategy: (a slide from my previous talk, Oct. 99) Can we cut in Z using TSF position info from stereo SLs? Stereo SLs --> Z Axial SLs --> DOCA DOCAZD Current “trigger volume” Possible improved “trigger volume”?? What to expect? The answer is in the TSF data we already have! Ted Liu, July 18,00, idea on Ztrigger

Ted Liu, July 18,00, idea on Ztrigger Other related issues: Drift Chamber How to bring the fine phi information for stereo SLs? First look at how current TSF pass the information to downstream (BLT&PTD). TSF engine for axial SLs To backplane hits from axial layers Trigger data 24 Gbits/s PTD data formatter 16 bits @clk30 Input formatters what’s missing BLT data formatter 4 bits @clk30 hits from stereo layers TSF engine for Stereo layers Ted Liu, July 18,00, idea on Ztrigger Track Segment Finder (x24)

Ted Liu, July 18,00, idea on Ztrigger Drift Chamber If we remake all TSFs, then it is straight forward: add traces from TSF stereo engine FPGA to PTD formatter FPGA(use bigger component, more pins), and use more pins on backplane TSF engine for axial SLs To backplane hits from axial layers Trigger data 24 Gbits/s PTD data formatter 16 bits @clk30 Input formatters Add traces BLT data formatter 4 bits @clk30 hits from stereo layers TSF engine for Stereo layers Pros: well defined simple hardware modifications Cons: have to remake all TSFs Ted Liu, July 18,00, idea on Ztrigger Track Segment Finder (x24)

Ted Liu, July 18,00, idea on Ztrigger Drift Chamber If we DON”T remake all TSFs, then life is more complicated: One possibility (as I mentioned long ago) is to give up some fine phi info for axial SLs and pass fine phi info for stereo layers. This can be done in Input Formatters (VHDL code change). TSF engine VHDL code needs some modification as well. TSF engine for axial SLs To backplane hits from stereo layers Trigger data 24 Gbits/s PTD data formatter 16 bits @clk30 Input formatters BLT data formatter 4 bits @clk30 hits from axial layers TSF engine for Stereo layers Pros: can use all existing TSF hardware Cons: need new simpler algorithm, performance issues? Uncertainties…. Ted Liu, July 18,00, idea on Ztrigger Track Segment Finder (x24)

Ted Liu, July 18,00, idea on Ztrigger A possible simpler algorithm: with only stereo SL fine phi info available This means no more DOCAD, but one can try to improve the current BLTz algorithm. With much finer information on SL2&3, one should be able to do much (?) better than current BLTz. Maybe outer stereo SLs fine phi info can also be helpful. Close to IP in z Cosmic ray events use SL2&3 separation in fine phi I haven’t thought much along this line, need more investigation… Off IP in z Ted Liu, July 18,00, idea on Ztrigger For details on BLTz, see http://babar-hn.slac.stanford.edu:5090/HyperNews/get/TrigOper/245.html

Ted Liu, July 18,00, idea on Ztrigger Summary of what I have said a new algorithm for a possible DOCAZ, assuming fine phi information for all SLs are available to the DOCAZ boards; (2) one possible way to modify TSF hardware to make fine phi information available for all SLs (3) Some thoughts on a possible simpler algorithm (improved BLTz) … Personal view: (1) + (2) is most promising Note: I came up with the idea (1) shown here on 4th of July while watching fireworks. Since then I have been busy with moving, so by no means this is a detailed design. Just some random thoughts in a few hours. Hopefully you will find them useful… I wish I had the time to do the TSF data analysis to finalize the new algorithm, but I am now paid to do other things….. I will be more than happy to help if someone is willing to give a try… Ted Liu, July 18,00, idea on Ztrigger

Ted Liu, July 18,00, idea on Ztrigger Drift Chamber One possible scenario DAQ Level 3 Filter DAQ All track segments found Trigger data 24 Gbits/s A,B Supercell hits GLT DZ? Fine phi info for all(?) SLs DOCAZD ?? Ted Liu, July 18,00, idea on Ztrigger Track Segment Finder (x24)

Ted Liu, July 18,00, idea on Ztrigger LER Ted Liu, July 18,00, idea on Ztrigger HER

Ted Liu, July 18,00, idea on Ztrigger Drift Chamber Upon a L1 Accept ... DAQ Using segments found by TSFs as seeds, fast algorithm applied to DCH data to further reject background... reduce the rate from 2 kHz to 100 hz. Level 3 Filter DAQ Trigger data Track segments found 24 Gbits/s Ted Liu, July 18,00, idea on Ztrigger L3 Event Display Track Segment Finder (x24)

Ted Liu, July 18,00, idea on Ztrigger

Ted Liu, July 18,00, idea on Ztrigger

The Drift Chamber ( DCH ) 10 superlayers of 4 layers each Axial and stereo alternate Ted Liu, July 18,00, idea on Ztrigger

Ted Liu, July 18,00, idea on Ztrigger Trigger Line Definition/Convention DCT Objects: B: short track reaching SL5, Pt ~120 MeV A: long track reaching SL10, Pt ~180 MeV A’: high Pt track reaching SL10, Pt > 800 MeV EMT Objects: M: minimal ionizing cluster, E >100 MeV G: intermediate energy cluster, E >300 MeV E: high energy cluster, E >700 MeV Y: backward barrel cluster, E >1 GeV IFT Objects: 1U: 1 high P muon in backward endcap o B*,M*...* means back-to-back objects(>120 ) D2 = 2B&1A, D2* = B*&1A D2*+ = B*&1A&1A’ , A+ = A&A’ Ted Liu, July 18,00, idea on Ztrigger

Ted Liu, July 18,00, idea on Ztrigger Drift Chamber Upon a L1 Accept ... DAQ Using segments found by TSFs as seeds, fast algorithm applied to DCH data to further reject background... reduce the rate from 2 kHz to 100 hz. Level 3 Filter DAQ Fine position info for segments found for all superlayers Trigger data 24 Gbits/s Currently TSF provides fine position info for all SuperLayers to L3, only axial SLs info passed to PTD. Ted Liu, July 18,00, idea on Ztrigger Track Segment Finder (x24)

Ted Liu, July 18,00, idea on Ztrigger Trigger Lines for Hadronic Events run9304 Requirements: B Physics Pure DCT CP Channels: high eff. Non-CP channels: high + precise eff. DCT + EMT Continuum High & precise eff. for background sub. Pure EMT Strategy for eff. Measurements: orthogonal lines redundant lines record all trigger DAQ data prescaled lines Ted Liu, July 18,00, idea on Ztrigger

Ted Liu, July 18,00, idea on Ztrigger Use orthogonal DCT-EMT lines to study eff. From Su Dong Total eff for hadron skim: (EMT OR DCT) > 99.3% Ted Liu, July 18,00, idea on Ztrigger

Ted Liu, July 18,00, idea on Ztrigger run9304 Trigger Lines for non-physics Events Requirements: Luminosity, calibration: 2-prong ee, High + precise eff. Pure DCT Calibration, beam monitor: 1-prong ee, DCT + EMT  only Pure EMT Background monitoring Background&Trigger studies Ted Liu, July 18,00, idea on Ztrigger

Ted Liu, July 18,00, idea on Ztrigger Trigger Lines for  and 2 Events Requirements:  Physics Pure DCT Rare & Asy.: high eff. Branch Ratios: precise eff. DCT + EMT 2 Physics precise eff. Pure EMT Shortcomings: All unprescaled lines have high Pt cut (800MeV) and with back-to-back requirement. No unprescaled orthogonal lines. All high eff. Lines have to be prescaled. Expected @ high background rate, will try to improve… add 2BM+1AM, lower Pt cut? Ted Liu, July 18,00, idea on Ztrigger

Ted Liu, July 18,00, idea on Ztrigger L1 Strategy to improve performance Better Combination of trigger lines: DCT+EMT phi matching Give up some orthogonal lines ... Improve trigger objects: Short-term: PTD ---> DOCAD Long-term: DOCAD --> DOCAZD? Need good understanding of background --> next Ted Liu, July 18,00, idea on Ztrigger

Ted Liu, July 18,00, idea on Ztrigger LER HER Single beam LER HER L1 pass thr. events Z distribution From S. Petrak Ted Liu, July 18,00, idea on Ztrigger

Ted Liu, July 18,00, idea on Ztrigger LER HER LER HER Single beam L1 pass thr. events x-z view Ted Liu, July 18,00, idea on Ztrigger Many tracks from beampipe: off Z --> off IP in x-y

Ted Liu, July 18,00, idea on Ztrigger Drift Chamber DCT Trigger Hardware Binary Track Linker (BLT x1) Coarse data for all supercell hits Trigger data 24 Gbits/s A, B 16 GLT 16 A’ Fine position data for segments found for axial SLs PT Discriminator PTD (x8) New idea Ted Liu, July 18,00, idea on Ztrigger DOCAD Track Segment Finder (x24) (only firmware change)

Ted Liu, July 18,00, idea on Ztrigger Drift Chamber Trigger ( DCT ) The heart of DCT is the Track Segment Finder TSF continuously live image processor A novel method: using both occupancy and drift-time information, to find track segments continuously with: time resolution of ~ 100 ns, event-time jitter window ~ 100 ns spatial resolution ~ 1 mm used for track Pt Discrimination (1) send segment patterns downstream for L1 trigger decision making Upon a L1 accept: (2) send segment patterns to the DAQ system for use in Level 3 ... Track Segment Finder Ted Liu, July 18,00, idea on Ztrigger Use 24 TSF modules

Ted Liu, July 18,00, idea on Ztrigger

Ted Liu, July 18,00, idea on Ztrigger

Ted Liu, July 18,00, idea on Ztrigger Current PTD algorithm New DOCAD algorithm (baseline design: simple algo.) A10 seed x x 800MeV Pt threshold (800MeV) 850MeV SL7 900MeV SL7 1 GeV SL4 SL4 SL1 SL1 x x IP IP 4 hits on one track with ~1mm, should be able to tell whether the track is from IP Tracks (above threshold) coming from IP should leave all the hits in one of the slices Tracks not coming from IP will most likely leave hits in different slices Ted Liu, July 18,00, idea on Ztrigger

Ted Liu, July 18,00, idea on Ztrigger Apply DOCAD algorithm to TSF data Hadron skim: signal Effect on Signal: PTD on Use hadron skim (~10% bkg) ~ 4% loss at turn on DOCAD on Effect on Background: Use single beam run L1 pass thr events Max Pt in the event 40% rejection on A’ line with simple algorithm PTD on Background rejection: 40% The goal here is not to find the best algorithm possible, but one which is easy to be implemented and with good performance DOCAD on Ted Liu, July 18,00, idea on Ztrigger LER single beam run: background

Ted Liu, July 18,00, idea on Ztrigger Require 3/3 in ALL slices DOCAD algorithm: possible improvement TSF can determine segment location with 1 mm resolution only for 4/4 patterns But 20% signal loss The resolution is degraded for 3/4 patterns: Due to cell ineff.  1 2 x x x x x = x x + x x x x 3/4 4/4 4/4 1 <  < 2 calibrating 3/4 patterns should help 70% bkg rejection! using the  information should help (baseline design ignored ) Ted Liu, July 18,00, idea on Ztrigger Currently 3/4 pattern LUT is derived from 4/4 patterns