From wischnew@ifh.de Thu Jun 28 19:04:03 2001 Date: Sat, 10 Feb 2001 05:04:49 +0100 (MET) From: Ralf Wischnewski To: amanda-c // mailing list Subject: MuonRates, StringTrigger, Muon-DAQ Dear all, here's a brief summary on Muon Rates and (some of the ) new features of the Muon-DAQ. New features installed might need fine tuning, some might already be done by Steve after I left pole 24hrs ago. For StringTrigger discussion, see end of this mail. A. TRIGGER setup ---------------- We are running the following trigger: 1. A-II Majority: >=24 (as in 2000) 2. String Trigger: 7/11 and 6/9 (B-4 strings) 3. Spase 4. Amanda-A 5. A-B coincidences 6. Prescaled lower multiplicty: >=4 at <1Hz 7. TDC-calibration: at 0.1Hz on 4 TDC channels (dead OMs) B. Monitoring various counting rates ------------------------------------ 15 rates are monitored deadtime-free with an SIS3808 200MHz counter (the "SN-counter" board). This includes: - true trigger rates A-II, S-2, StringT, A-A, raw presacler rate, ... - A-II majority rate at >=50 and >=100 C. Rates -------- Here are the rates as measured on Feb 7th/8th. Small changes migth apply, since a few 'bad channels' showing up and disappearing spontaneously. rate_meas, rate_true and LifeTime are the "measured" rate (i.e. "to_tape"), the deadtimefree true rate (in Hz) and the corresponding relative lifetime (in %) at Majority trigger level MAJ. Run MAJ Rate_meas Rate_true Lifetime DataRate (kB/s) ----------------------------------------------------- A-II majorityTrigger ONLY ----------------------------------------------------- 3085 24 73.4 88.0 83.4 ~85 3088 22 85.3 105.6 80.8 ~95 3086 26 61.0 72.0 85.2 ~75 3087 28 50.5 57.7 87.6 ~66 ----------------------------------------------------- A-II Majority & String Trigger ----------------------------------------------------- 3090 24 89.8 112.7 79.9 ~96 ----------------------------------------------------- The exclusive String trigger rate is 15.7Hz (=additional RAW rate), compared to 12Hz when measured with Jan 2 weeks ago, i.e an increase of ~30% ! No measurements done with Str-Trigger settings to 6/9 for all strings, but a linear scaling would give an additional rate of 25Hz*1.30=33Hz RAW !! The loss in HE-neutrino physics is not only the additional deadtime introduced, but needs to be compared with the RAW trigger rate, that is obtained with same deadtime at a lower Majority threshold: If 80% deadtime is accepted for Stringtrigger 7/11, then without Stringtrigger you can run at Majority >=22 instead of 24 (deadtime 81%, see table above). The to-tape rate is then 85.3 Hz, i.e the gain will be (85.3-73.4)Hz / 73Hz = 16 %. This is what we loose for HE nu's when applying 7/11 Stringtrigger. If going to StringTrig 6/9 I estimate this HE physics loss to be >30%. I recommend, not to use StringTrigger 6/9 for the whole array, until MC-Background estimations and analysis of 7/11 data are in some good shape. Cheers, Ralf. ----------------------------------------------------------------------- | Ralf Wischnewski | | | | Deutsches Elektronen-Synchrotron DESY | Phone: +49 33762 77348 | | Platanenallee 6 | Fax: +49 33762 77330 | | D-15738 Zeuthen Germany | E-Mail: wischnew@ifh.de | -----------------------------------------------------------------------