1. A. Lai – 18/10/2006 – L0 workshop: Muon BX Time Alignment 1 The BX Alignment in The Muon System Summary System peculiarities concerning timing issues System peculiarities concerning timing issues System features System features The test beam experience The test beam experience Alignment strategies: Alignment strategies: Without beam Without beam With beam With beam Alignment based on the beam structureAlignment based on the beam structure Interaction triggersInteraction triggers Muon haloMuon halo Muon reconstructionMuon reconstruction Commissioning and “pilot” run issues After discussions and re-discussions with Bepo, Richard, Sandro et al.

2. A. Lai – 18/10/2006 – L0 workshop: Muon BX Time Alignment 2 Muon System (MS) timing-related peculiarities The MS can be perfectly subdevided in 4 “equal” parts The MS can be perfectly subdevided in 4 “equal” parts We have 120,000 FE channels We have 120,000 FE channels Around 50,000 signal cables (LVDS) of different lengths Around 50,000 signal cables (LVDS) of different lengths 20 different types of detectors, with different time responses 20 different types of detectors, with different time responses Time spectra from detectors are relatively wide Time spectra from detectors are relatively wide We have to tag and send data to the L0  trigger before the L0 buffer We have to tag and send data to the L0  trigger before the L0 buffer

3. A. Lai – 18/10/2006 – L0 workshop: Muon BX Time Alignment 3 Time alignment system features: front-end side Knobs Coarse pitch (SYNC, ODE) TTCrx settings (per board = 192 channels) BX offset (per SYNC = 8 channels) BX preload (at BCR) (per SYNC = 8 channels) L0 buffer latency (per SYNC = 8 channels) Input pipeline (per channel) Trigger output pipeline (per channel) Fine pitch (DIALOG, on FEE) 1.6 ns x 31 steps (per single channel) Monitoring Two types of histograms: Fine time histograms Coarse time histograms (starting of the orbit). They are visible on the ODE (selecting each single channel by ECS). FTH can be built either on input hits or on L0- passed hits Pulsing system Each FE channel can be pulsed at a programmable BX (“primitive” ECS)

4. A. Lai – 18/10/2006 – L0 workshop: Muon BX Time Alignment 4 System Time Alignment Step 0, without external triggers:  Align BC counters (SYNC chip, ODE controller, TTCrx). On a given L0yes, the BX counter on the ODE controller, the TTCrx BX counter and the BX counter at the output of the L0 buffer must all be equal Data from FEE BX tag BCR, L0R preset/get BC counter via ECS To L0 trigger L0yes L0 buffer DPRAM 256 L0 derandomizer DPRAM 128 Inside SYNC: Programmable L0 buffer latency (R/W pointers) Start W_Add Start R_Add To ODE controller BXId(3:0) We fix the L0 latency on Odin, then we align playing with ODE timing parameters. The effective alignment is checked on a L0yes, looking at dedicated flags. On request, also the 4 LSB of the BX counter can be directly checked on the FIFO of the ODE controller. (BCR) The Muon FE has “to BCId” data BEFORE the L0 buffer

5. A. Lai – 18/10/2006 – L0 workshop: Muon BX Time Alignment 5 Simplified Scheme of System electronics @ SPS (Sept06) ODIN SPS signals TFC controls Transition Board ODE (x2) TELL1 30 CARDIAC Chains (48 +192 ch.s out) Service Board Optical splitter Optical data Links Tell1 ECS (CCPC) PVSS-based control system FEE setup and control program I 2 C chains (Auxiliary trigger) (L0 yes) TFC controls Eth. switch DAQ PCs L0  processor ODE setup and control program Trigger sc. and trigger logic TFC controls TELL1 TFC controls DAQ console LVDS (15m) LVDS (20m) CANbus ELMB Data Event hits (x2)

6. A. Lai – 18/10/2006 – L0 workshop: Muon BX Time Alignment 6 System Time Alignment: Coarse BX alignment in the SPS TB Known effective L0 latency of 160 cycles starting from an external trigger (no L0 processors and L0DU, of course): around 145 cycles. Known signal cable lengths: 20m Evaluated Trigger delay All channels in each chamber considered in time among themselves (small size system) The adopted procedure was the following: 1.Set an initial L0 latency = 145 cycles 2.Given a trigger, generate13 consecutive triggers (…), centering the triggered event inside the window (L0 latency = 145 – 6  event on the 7 th slot) 3.Set the Odin in such a way to issue a max number of triggers = 13 4.Look at the data on the MEP buffer (fast) or on the DAQ PC (slower). 5.Change the ODE/FEE settings until the alignment is reached Initial hints: In order to align received hits/events (readout data) and triggers The key parameter is the L0 accept latency

7. A. Lai – 18/10/2006 – L0 workshop: Muon BX Time Alignment 7 3GEMMWPC Coarse BX alignment Histograms constructed from acquired data after ~ 5-10 scintillator triggers t slot # N of events SYNC number Having the same Odin and ODE settings, the same cable lengths, the MWPC signals appeared at first as arriving two BX before the 3GEM ones (detector response) Vth = 4 fC Vth = 6.5 fC The MWPC were delayed by 2 cycles and then all the signals centered again w.r.t. the trigger reducing the L0 latency Finally an alignment was obtained within +/- 1 slot 3GEM MWPC

8. A. Lai – 18/10/2006 – L0 workshop: Muon BX Time Alignment 8 Fine Time on data: before alignemnt MWPC GEM Slot # 1 2 3 4 5 6 7 8 9 10 11 12 13 In this case, we wanted to center on the 3 rd slots

9. A. Lai – 18/10/2006 – L0 workshop: Muon BX Time Alignment 9 Fine Time on data: after alignemnt MWPC GEM

10. A. Lai – 18/10/2006 – L0 workshop: Muon BX Time Alignment 10 3GEM fine time (before fine alignment) Fine Time alignment using SYNC histograms 3GEM fine time (after fine alignment) After BX retuning X MWPC fine time

11. A. Lai – 18/10/2006 – L0 workshop: Muon BX Time Alignment 11 Different methods of time alignment 1 – Without beam

12. A. Lai – 18/10/2006 – L0 workshop: Muon BX Time Alignment 12 Scheme of the synchronous pulsing system SB FEB SB TFC The PDM issues a pulse synchronous to a given BCId Backplane distribution (<< 1 m) 1 12 FEB ECS distribution: I2C chains (LVDS cables, 10-15 m) CARIOCA DIALOG CARIOCA Pulse_In Next DIALOG can program the pulse delay to the CARIOCA input PDM TTCrx

13. A. Lai – 18/10/2006 – L0 workshop: Muon BX Time Alignment 13 Some remarks about the Pulsing System (PS) 1.The pulse distribution is not equalized “naturally”. 2.Even without perfect equalization, the PS can be used as it is for a rough alignment (+/- 1 cycle). 3.In principle, it could be perfectly equalized using the DIALOG programmable delays, compensating for the different travel distances (in primis, cable lengths and detector responses)  Cable length data base (information exist, to be built) Considering the beam conditions of the pilot run, we now plan to exploit the full potentiality of the PS in order to get a good alignment already without beam

14. A. Lai – 18/10/2006 – L0 workshop: Muon BX Time Alignment 14 Use of the pulsing system We will perform “pulsing” runs already in the commissioning phase, as soon as a good part of the detector and system electronics are installed This can be done using TFC signals emulating the nominal bunch structure The TFC can also issue triggers in correspondance with the programmed BXId on the PDM. In such a way regular data taking is possible. The aim/result of these runs would be: To test system connectivity in detail (also for debug purposes); To build and check a “time position map” of the system To realize a time system alignement at the level of +/- 1 BX (or better) TFC PDM ODE (L0 buffers) Pulse Detectors Hits DAQ L0y

15. A. Lai – 18/10/2006 – L0 workshop: Muon BX Time Alignment 15 The L0  can be added in the chain. If it is set to accept the event, we could also “measure” and align the L0  latency. We could go further Also, If we align at least some towers of the MS using Pulsing, one could also imagine to emulate (pulsed) tracks in the apparatus. Would this be useful for the L0  commissioning, before the beam ? - Also, If we align at least some towers of the MS using Pulsing, one could also imagine to emulate (pulsed) tracks in the apparatus. Would this be useful for the L0  commissioning, before the beam ? TFC PDM ODE (L0 buffers) Pulse Detectors Hits DAQ L0y Hits+BXId L0  Processor L0  answer (yes)

16. A. Lai – 18/10/2006 – L0 workshop: Muon BX Time Alignment 16 Different methods of time alignment 2 – With beam

17. A. Lai – 18/10/2006 – L0 workshop: Muon BX Time Alignment 17 One TDC histogram per logical channel is automatically filled in the SYNC chip and can be readout through ECS. The same histograms can be filled on a BX per BX basis, in such a way to reproduce the bunch structure locally, at the level of the ODE boards, where data are BX-tagged 1. SYNC histograms and bunch structure Theoretically, this method provides the exact position of the given FE channels w.r.t. the absolute BX number. This method is very effective in the highly populated stations, less in the others. It requires relatively high Luminosity and for this reason will probably not be effective in the foreseen scenario of the startup phase. But it will be there... Simulated SYNC histograms in the case of a 75 ns bunch structure

18. A. Lai – 18/10/2006 – L0 workshop: Muon BX Time Alignment 18 2) Interaction trigger from Cal(l)o(t) This method is very similar to the one used in the recent SPS TB: 1.Start from a  aligned setup 2.Trigger on very isolated MB triggers (in this case it helps !!!) from Calo, 3.generate artificially 3-5 consecutive triggers (or more, if possible) 4.In the data, look for the hits in the super-event window 5.Re-adjust the latencies consequently 6.Check alignment consistency with the other subsystems As the Calo trigger and BX is already aligned to the orbit, this method is compatible with the one using the bunch structure. Interaction trigger are generally “dirty” and not perfectly suitable for time alignment. The best, of course, would be to trigger on MIPs (  )

19. A. Lai – 18/10/2006 – L0 workshop: Muon BX Time Alignment 19 3) Muon halo with the Calorimeter...But: Not sufficient for full Muon Detector commissioning - no muon halo events in the outer regions - M1-M5 are projective from IP… Muon halo could be useful to accelerate time alignment of the inner part of Muon Detector. Triggering on muons would give clean tracks, perfectly in time

20. A. Lai – 18/10/2006 – L0 workshop: Muon BX Time Alignment 20 The TDC histogram of muon hits permits the best time alignment. This method must be used anyhow (for M2-M5) before Physics Runs to maximize trigger efficiency. We will use this method when we already have a sufficiently good prealignment and a reasonable Muon Trigger, possibly a MuonID at HLT level. The problem at low luminosity will be the available statistics in the less crowded outer regions. 4) Muon identification through a “HLT like” algorithm + DAQ, look at TDC of Muon hits

21. A. Lai – 18/10/2006 – L0 workshop: Muon BX Time Alignment 21 Program for alignment Starting from the inner regions, we foresee to reach a good pre-alignment on at least a significative part of the System (if not on the whole System), before the arrival of the beam B) When the beam is there, we will widely exploit the HCAL features, concerning both the MB and the muon (halo) triggers. The alignment will be found by reading consecutive triggers. C)When a reasonable alignement is reached, the L0  enters the game D) Meanwhile, MuonId algorithms are used to refine the alignment A) As soon as a complete tower of the MS is installed and equipped, start commissioning in the pit. In this first phase commissioning will consist in: 1. System debugging (missing channels, cabling errors...) 2. System time alignment (pulse system) 3. Possibly, combined tests with the L0  Points 2 and 3 require a working Odin in our partition. This exercise will continue on a tower basis while the MS is being installed.

22. A. Lai – 18/10/2006 – L0 workshop: Muon BX Time Alignment 22 Installation+commissioning Schedule (Sept. 06) Hardware situation is fair We will start Electronics (functional) commissioning in March

23. A. Lai – 18/10/2006 – L0 workshop: Muon BX Time Alignment 23 1.An ECS structure working at system level. We have simple panels to control FE boards (CARDIAC, ODE), but this are still inadequate at the system level (and are not in PVSS). A lot of work must be done in this direction. 2.Also, an important amount of work is to be done on System Data Base handling, which can be crucial in the pre-alignment phase. 3.Phaenomenology concerning pilot run conditions should be studied better: - Hit multiplicity per region, - statistics / distribution of μ from beam gas, - rate per channel and the needed running time with the different methods.... What is still lacking

24. A. Lai – 18/10/2006 – L0 workshop: Muon BX Time Alignment 24 Conclusions We will get a good time alignment already without beam By using Calo-generated triggers we can verify the alignment with the beam in a relatively fast way (1-2 days?) in such a way to let the Muon trigger enter the game as soon as possile This will be “easy” for the inner part of the detector (R1-R2), more problematic for the outer regions (to be studied better), where we will probably have to rely on the pulsing alignment. Work to be done on the ECS side.