Measuring electronic latencies in MINOS with Auxiliary Detector
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This document discusses measuring electronic latencies in the MINOS experiment using an auxiliary detector (AD). It first provides an overview of the MINOS experiment and its goals. It then explains the time-of-flight principle for measuring latencies and describes how an AD was set up at both the Near and Far detectors to timestamp events. The ADs allow cancellation of systematic errors from differing readout systems. Finally, it discusses how AD and detector timestamps are matched to measure relative electronic latencies and improve the time-of-flight measurement.
Measuring electronic latencies in MINOS with Auxiliary Detector
- 1. Measuring electronic latencies in MINOS with Auxiliary Detector Son V. Cao University of Texas at Aus@n (on behalf of the MINOS collabora@on) June 14th 2012 MINOS overview TOF principle AD setup Measurement Summary FNAL2012 New Perspec@ves
- 2. 2 MINOS overview TOF principle AD setup Measurement Summary Main Injector Neutrino Oscilla@on Search (MINOS) 734 km Near det. 1.0 kton Far det. 5.4 kton ü High intensity muon neutrino beam produced at Fermilab ü Two detectors: reduce systema@c errors, magne@zed to dis@nguish interac@ons ü Near Detector to measure ini@al beam composi@on, predict no-‐oscilla@on spectrum at Far Detector ü Long baseline (734km) Time of Flight (TOF) (1st measurement in 2007) We revisit TOF with more staDsDcs and refined understanding of system ⌫µ and ¯⌫µ
- 3. 3 MINOS overview TOF principle AD setup Measurement Summary v = d21 (t2 t1) Basic principle: Real measurement: P1(t1) P2(t2) Distance d21 t1 t2 Find to minimize the likelihood between and In 2007, used 473 FD events: 2. Time of Flight (TOF) principle t21 P2(t2)P1(t1) Need to understand the Dming system beNer!!! Time shiP by TOFv Baseline à TOFc t = 126 ± 32(stat.) ± 64(syst.) ns (68% C.L. ) (v/c 1) = 5.1 ± 2.9 ⇥ 10 5 (68% C.L.) Source of latency Uncertainty 2007 ND electronic latencies 32ns FD electronic latencies 3ns F/N detector rela@ve latencies 9ns
- 4. 4 3. Auxiliary Detector (AD) MINOS overview TOF principle AD setup Measurement Summary Auxiliary Detector at the back end of Near Detector Auxiliary Detector in the middle of two Super-‐Modules at Far Detector ⌫ beam Auxiliary Detector Dmestamps muon, resultant parDcle of neutrino interacDon, and matches with events recorded in real detector
- 5. ü Readout system has complicated latency, not easy to measure ü Two readout systems of MINOS detector are not the same systema@c error ü Using two iden@cal readout systems, Auxiliary Detector (AD), can cancel out this error 5 Goal: measure the latencies and miDgate the systemaDc error using a simple auxiliary system Near Far UTC Dme ⌫ beam AD AD 3. AD setup: mo@va@on MINOS overview TOF principle AD setup Measurement Summary
- 6. 5. Event @mestamp with AD 3. AD setup: event @mestamp MINOS overview TOF principle AD setup Measurement Summary 6 ü Passage of muon produces blue scin@lla@on light ü Wavelength-‐shi`ing fiber absorbs and shi`s scin@lla@on light ü Signals are mul@plied by photomul@plier (PMT) and used as “STOP” signal ü Timestamp “STOP” signal with a “START” reference signal in each detector RelaDve electronic latency between ADs and real detectors is calculated by event matching ScinDllator paddle PMT
- 7. 7 Timing diagram Timing system overview MINOS overview TOF principle AD setup Measurement Summary Beam structure ( 53MHz unit) ~10 us ü Accelerator generates signal, named $74, tell kicker magnet to prepare extrac@ng the proton beam ü Each spill lasts about 10us ü At ND, Front-‐End boards start window, labeled SGATE, to collect data ü At FD, another window, labeled SS Window, is opened to capture data at the @me spill arrives
- 8. 8 5. Matching AD and ND Ending edge Matching AD and ND time distribution (ns) 11100 11150 11200 11250 Numberofevents/2ns 0 500 1000 1500 2000 Auxiliary Detector Near Detector MINOS Preliminary Dip Dip Matching AD and ND time distribution (ns) 4650 4700 4750 4800 Numberofevents/2ns 0 1000 2000 Auxiliary Detector Near Detector MINOS Preliminary Matching AD and ND time distribution (ns) 1450 1500 1550 1600 Numberofevents/2ns 0 1000 2000 3000 Auxiliary Detector Near Detector MINOS Preliminary Leading edge Ending edge Dip Time relative to spill (18.83ns bins) 200 400 600 Numberofevents/18.83ns 0 100 200 300 400 MINOS Preliminary MINOS overview TOF principle AD setup Measurement Summary Matching between Auxiliary and Near Detector distribu@on 4. AD measurement at Near Beam structure ( 53MHz unit) ~10 us $74 SGATE Time of μ at AD Time of μ at ND Use $74 and SGATE as “START” signals respec@vely for Auxiliary and Near detectors 8 AD data at Near 19ns Bucket structure
- 9. 9 Offset between SGATE and $74 at AD(ns) 212850 212900 212950 Loglikehood 0 2000 4000 6000 8000 MINOS Preliminary Distribu@on comparison MINOS overview TOF principle AD setup Measurement Summary 4. AD measurement at Near 19ns ü Calculate likelihood of AD-‐ND distribu@on comparison as a func@on of SGATE-‐$74 “offset” ü Likelihood reflects very well the bucket structure but the true peak is not clear. ü SGATE-‐$74 @me interval is not true offset. SGATE is programmably lined up with 53.1MHz clock @ck. ü The direct measurement of SGATE-‐ $74 @me interval also shows two peaks separated by 19ns. SGATE -‐ $74 @me interval Number of events
- 10. 10 Offset between SGATE and $74 at AD(ns) 212850 212900 212950 Loglikehood 0 2000 4000 6000 8000 MINOS Preliminary Entries 5121 Mean 212908.120 RMS 16.877 Offset between SGATE and $74 at AD (ns) 212850 212900 212950 213000 Numberofevents/2ns 0 50 100 150 Entries 5121 Mean 212908.120 RMS 16.877 MINOS Preliminary Distribu@on comparison MINOS overview TOF principle AD setup Measurement Summary 4. AD measurement at Near 19ns Event-‐by-‐event matching No latency included ND -‐ AD latencies = 36 +/-‐ 4ns ü AD is synchronized to ND DAQ, permined to match in event-‐by-‐event basis. ü These peaks agrees with those from distribu@on comparison ü “Offset” measured by AD includes the electronic latencies of AD and ND ü Calculate AD-‐ND electronic latency by comparing with @me interval from direct measurement (mean of the peak is used) AD-‐ND latencies included 4ns
- 11. 11 5. Matching AD and ND MINOS overview TOF principle AD setup Measurement Summary 4. AD measurement at Far FD -‐ AD latencies = 12 +/-‐ 2ns Entries 81 Mean 98.602 RMS 8.083 / ndf2 57.218 / 47 Constant 1.028±23.342 Mean 0.102±96.579 Sigma 0.123±2.145 Offset between AD and FD (ns) 60 80 100 120 140 Numberofevents/2ns 0 10 20 Entries 81 Mean 98.602 RMS 8.083 / ndf2 57.218 / 47 Constant 1.028±23.342 Mean 0.102±96.579 Sigma 0.123±2.145 MINOS Preliminary ü Use cosmic ray events for matching ü Use PPS signals from Cs Clock and GPS as “START” signals respec@vely for Auxiliary and Far detectors Cs PPS GPS PPS Time of μ at AD Time of μ at FD Monitored by Agilent 53230A
- 12. ü The ADs are necessary for mi@ga@ng the electronic readout latencies ü The ADs has already installed and first results are used for TOF retrospec@ve analysis in 2012 ü The AD will be used in the next phase of Time Of Flight measurement 12 Summary Summary Source of latency Uncertainty 2007 Uncertainty 2012 ND electronic latencies 32ns 4ns FD electronic latencies 3ns 2ns F/N detector rela@ve latencies 9ns 1ns MINOS overview TOF principle AD setup Measurement Summary Full Spill approach: TOFv – TOFc = -‐18 ± 11 (stat.) ± 29 (syst.) ns Wrapped Spill approach: TOFv – TOFc = -‐11 ± 11 (stat.) ± 29 (syst.) ns
- 13. 13 5. 4. MINOS plans 13 Backup: Fit at peaks MINOS overview TOF principle AD setup Measurement Summary Entries 5121 Mean 212908.120 RMS 16.877 / ndf2 28.844 / 13 Constant 7.354±155.895 Mean 0.159±212892.656 Sigma 0.105±3.404 Offset between SGATE and $74 at AD (ns) 212850 212900 212950 213000 Numberofevents/2ns 0 50 100 150 Entries 5121 Mean 212908.120 RMS 16.877 / ndf2 28.844 / 13 Constant 7.354±155.895 Mean 0.159±212892.656 Sigma 0.105±3.404 MINOS Preliminary Entries 5121 Mean 212908.120 RMS 16.877 / ndf2 125.557 / 12 Constant 7.629±141.745 Mean 0.198±212911.391 Sigma 0.267±5.596 Offset between SGATE and $74 at AD (ns) 212850 212900 212950 213000 Numberofevents/2ns 0 50 100 150 Entries 5121 Mean 212908.120 RMS 16.877 / ndf2 125.557 / 12 Constant 7.629±141.745 Mean 0.198±212911.391 Sigma 0.267±5.596 MINOS Preliminary
- 14. 14 5. 4. MINOS plans 2007 Analysis Phase I (6 months) Phase II (9-‐12 months) Phase III (2013 and on MINOS+ era) Re-‐analysis exis@ng data, reduce dominant systema@c errors Hardware improvement More hardware improvement , update beam energy 64 ns 18-‐33 ns 11-‐18 ns 2-‐7 ns • (A) Resurvey the distance between two detectors • (B,D) Re-‐es@mate the length of cables • (F) Bener synchroniza@on systems • (C,E,G) Auxiliary detector to measure delays of readout system 14 Backup: Systema@c revisit MINOS overview TOF principle AD setup Measurement Summary
- 15. 15 5. Backup: two TOF approaches MINOS overview TOF principle AD setup Measurement Summary • NuMI neutrinos spill lasts about 10us • Spill subdivided into 1.619 us batches (5 or 6 batches) • 95ns gap between batches Full Spill approach: ü ND event @me within spill predicts FD @ming distribu@on ü Find best value of Time of Flight to match data Wrapped Spill approach: ü Wrap events within batch in each detector ü Fit two gaps in two detector and subtract them
- 16. 16 5. Backup: update @ming system Use TWSTT* or PPP *TWSTT: Two-‐Way Satellite Time Transfer PPS: Point Posi@on System Near Far Rb clock • Current GPS has 100ns jiNer • Update precise and monitored sync btw Near and Far det MINOS overview TOF principle Recent TOF results MINOS plans AD setup Summary
- 17. From PMT to Amplifier to discriminator to Logic Unit NIM 715: five-‐channel constant fracDon Dming discriminator NIM Model 612A: 12-‐Channel PhotomulDplier Amplifie PMT 1 2 ns 2 ns 2 ns 2 ns Model 364AL: Dual 4-‐Fold Majority Logic Units 1 ns 1 ns 1 ns 1 ns 8 ns 8 ns 8 ns TDC TDC TDC PMT 2 Model 1880B: Dual Visual Scaler Design slightly different 17