“Physics Trigger” in protoDUNE: Function and Performance David Last, David Rivera, and Jonathan Sensenig June 6, 2019 Physics Performance Meeting 0
Outline Overall Trigger Structure Our “Physics” Trigger for protoDUNE Offline Algorithm Efficiency Current Status/Developments Discussion: How to measure online physics performance 1
Overall Structure for DUNE Trigger Candidate Algorithms Our efforts have been focused on Module the process of Trigger making these decisions in the last two stages. 2
Our Basis for Candidate Decisions 50 microsecond Clustering Window (D. Rivera: DUNE-doc-9808-v1 ): Unlikely to get high pile-up from 39 𝐵𝑠 TPC Summed ADC (TADC): Total Sum of primitive Summed ADC over all ticks above threshold in one TPC Utilize maximum between two TPCs per Clustering Window Adjacency/Clustering* : Two different methods for Counting Wires hit in a time window Time Over Threshold in ticks (TOT): Single-wire, single-primitive maximum per Clustering Window Wire ADC (WADC): Single-wire, single-primitive Summed ADC maximum per Clustering *- Focus on Adjacency for Window now due to computation speed. 3
Our Basis (Visually) Modified (due to chosen nomenclature) from WADC David Rivera’s talk on y the Data Selection Call on February 15, 2019. z x 4
Our “Module” Level Trigger for Horizontal Cosmics Define “horizontal”: Crossing all APAs on the same side of the TPC which have online hit-finding/trigger primitive geneartion Take Candidates with high adjacency (threshold discussed in later slides) When a Candidate is issued, the end points (channel and time points) of the largest adjacency (cluster size) of wires are saved as part of the candidate “Stitch” together the tracks, and issue trigger if “sufficiently” crosses all APAs 5
Simulated Events 54,000 100 GeV Horizontal Muons (Crossing APAs instrumented with FELIX), with SCE. This is a top-down view with left as upstream. Cathode in the center. 6
Simulated Events Collection Wire Tick 7
Simulated Events Collection Wire 50 us Tick 8
Adjacency Distribution (Threshold 15 ADC) Distribution of all non-empty APA*windows for APAs instrumented with FELIX 9
Selection, in Detail Take All Candidates in an Event where Adjacency Exceeds (or equals) 50 Call two Adjacent-In- Time Candidates “stitched” if the following are true: Up to gap of 1 in channels hit Gap of no larger than 2 ticks in time (10 ticks if across APAs) Slope of “track” different from previous slope by no less than 5% of largest possible slope If total “stitched track” has at least 450 wires hit in both APAs (presently instrumented), issue trigger 10
Implicit Assumptions/Details Current allowed channel gap sizes are a bit unrealistic, but tunable as necessary The stitching is done in increasing time order of candidates: The direction of successful tracks is monotonic in the channel-tick plane on large scales Could lose horizontal muons to small scatter Could lose horizontal muons due to large scale space charge effects 11
Performance Present Efficiency for triggering: Primitive Threshold ADC 15: ~10% Primitive Threshold ADC 18: same order, about 1% more efficient that threshold 15 Above, unexpected (more efficient higher threshold) result being sorted out: There is a possible physics explanation. Magnitude of efficiency likely due to being stringent conditions chosen to avoid fake triggers Trigger Candidate Output is generally as expected: ~54% of all non-empty windows (many in that tail near 0) 12
Offline To-Do for protoDUNE DAQ Tests Sort out the source of the efficiency differences between thresholds Test algorithm on random trigger data to get an idea of overall trigger rates/Limit rates as necessary 13
Integration Status/Schedule for protoDUNE DAQ Test Structure of first-implementation MLT exists, is listening to hits In progress confirmation that correct TPC data is being requested Structure of TCBR in development Hit sets need to be windowed into physically meaningful chunks, in development Once windowed, implement physics-based selection: Start with basic (e.g. nhits) and work up to more complete implementation of discussed horizontal muon trigger Unknown if other physics triggers in development 14
Discussion: Physics Performance Metrics Compare percentage of “offline triggers” in random trigger data to horizontal muon-triggered data (very basic test) Look at event displays of horizontal muon-triggered data (time- consuming, arguably more rigorous) Utilize CRT information independently tag events (Need to be careful about geometries): Could be used similar to point 1 on this slide Could be used to measure expected rate to compare to trigger rate Other Suggestions/Ideas? 15
A Pitch A Test that, if possible, I would want to do in protoDUNE while the beam is off. See what the current trigger candidate algorithms calculate in terms of its decision variables for windows that don’t contain cosmics. Essentially, issue a candidate for every window with a random trigger turned on so that all the calculated information is output, and then offline determine which windows had cosmics in them, so that we have a characterization of how the trigger candidate algorithms see noise/radiological backgrounds. Only concern is that there will be bleed in from cosmogenic neutrons, but all that does is give a more conservative estimate. 16
BACKUP 17
TADC for Horizontal Muons in protoDUNE MOST IS IN OVERFLOW… 18
WADC for Horizontal Muons in protoDUNE 19
TOT for Horizontal Muons in protoDUNE 20
Recommend
More recommend
