APA-Crossing Muons, Shower Recon Mike Wallbank University of She ffi eld 20/7/16
Update A few weeks ago, I started looking at through-going muons which pass through the APA frames • as a ‘way in’ to some 35ton data analysis — gave initial talk at this meeting on 8th June. Been a bit lot busy recently so little progress! I’m back working full-time now. • Two points from last talk: • The 35t was the first LArTPC with readout planes within an active volume so this is the first • time we can test these particular detector e ff ects. Initially, I am looking at validating the T0 given by the counters using these through-going • tracks. Will possibly lead to more studies… Not sure how well this method will work — but it’s giving some interesting results… • Also have my wild dream of trying to reconstruct some showers… • 2 M Wallbank (She ffi eld)
What I’ve Done/Doing Sliced and filtered on events with a NS/EW trigger such that the track passes through the APAs. • Runs 14427-14428, 14435-14470 (Alex’s good runs). • Note last talk I was only using NS triggers. However, I had an issue with track length in the • SDV — if using EW counters close to the frames I’m guaranteed a good amount of hits. Initial look at the T0: • Take tracks which pass through APAs and find the T0 as given by the counters; • Try varying the T0 within a range around the counter T0 to see if the tracks line up any • better; Use this to determine if the counter T0 is systematically o ff set in some way. • 3 M Wallbank (She ffi eld)
Idea: The T0 has the e ff ect of • making tracks from the di ff erent drift volumes misaligned. Correcting for T0 will join • the segments into a single straight line. In this first instance, this is • what I’m attempting to do! T0 4 M Wallbank (She ffi eld)
Hit Selection • Using a similar method to Dom and probably many others! T0 ‘correction’ 5 M Wallbank (She ffi eld)
‘Correct’ T0 Determination • Fit a straight line through all the points; • Determine the distance of each hit from this central axis; • chi-square: nhits ⌘ 2 ⇣ o i − e i X σ i i • distance of hit from axis is taken as observed — expected; • RMS of these distances taken as error. • Vary the T0 over a range and determine chi- sq for each: Split with 300 pre-trigger ticks 6 M Wallbank (She ffi eld)
T0 Distribution • I’ve attempted to automate this process so a distribution of T0 can be considered… My jobs are still running though :( • I’ll update next week (by which time they will have hopefully finished!). • Gut feeling is this method appears reliable enough to make some conclusions… but the initial results are quite a way o ff suspected. 7 M Wallbank (She ffi eld)
Finding Systematics? • Split with 300 pre-trigger ticks —> expect a T0 of ~300. • From the chi squared, it appears to favour ~365, and in the range 355 — 398 (+-1 chi-square). • I feel there’s something biasing the result more than the method… fair? • (I know we need more events! I’m working on it…) • Ghost triggers are discounted, varying the drift velocity (Tingjun suggested this could be a large source of systematic uncertainty) doesn’t seem to make huge di ff erences… 8 M Wallbank (She ffi eld)
Drift Velocity Uncertainty • I’ve tried varying the drift velocity to see what e ff ect this has on the uncertainty… • Here’s +- 20%… -20% +20% 389 358 375—422 348—363 • Even 2x nominal 250V/cm drift velocity converges around 350 ticks. 9 M Wallbank (She ffi eld)
Where From Here? • Obviously I’ll have to wait to run this over more events to see if this is the general trend. • I can’t see any immediate issues with the method however… Happy to be disagreed with though! • Any other ideas of things that can be a ff ecting these results? 10 M Wallbank (She ffi eld)
Aside: Standard Reconstruction • In my attempts to reconstruct some showers over the past few days I’ve run into a few issues with the reconstruction. • The main problem concerned the code unsticker and the waveform filter configurations: • The module label used by the filterwf module is Raw DigitModuleLabel (and also accepts the instance as a separate parameter) • Unless some configuration was happening that I’ve completely missed, this meant that the standard reco file used the default RawDigitModuleLabel configured in dunetpc (SplitterInput:TPC) so ignored the unsticker completely. I’d really like to remove this parameter • I changed the standard files in develop yesterday. for consistency… thoughts? 11 M Wallbank (She ffi eld)
Summary • Was hoping to have a lot more to show today but jobs are running, the problems with the shower reconstruction are taking a while to understand. • Hopefully next week I’ll have all this! … :) 12 M Wallbank (She ffi eld)
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