MDI meeting, Nov First look at Transient Recorder data Livio Piemontese Stan Ecklund and Mark Petree have installed – in the IR2 alcove – a 32 channel Transient Recorder, which digitizes and records 32 signals from PEP2 and Babar when triggered. The trigger is the “beam abort” signal, independent from where it comes from. The signals are read and stored in the TR’s memory. They are digitized every ms. Data are stored for various time intervals – typically 10s. A typical event is 4 Mbytes; in an average month (May2003) there are 566 events. The amount of information is enormous. Given the sheer size of the data, a systematic analysis has NOT been attempted so far. There MAY be there useful information to understand some of our background problems (sudden radiation spikes?). The files are in a PC in IR2. So far, data have been transported by car. In 2003, it is a shame. File names contain the date and time of the abort.
MDI meeting, Nov Which signals are recorded? The 32 channels can be grouped into: 17 CsI beam loss counters (Va’vra’s) 7 PEP2 “Beam Loss Monitors” 4 vacuum pumps 2 SVTRAD diamonds 2 microphones 2 “first_level trigger lines” (?): DCH and EMC The philosophy is (probably) to look where in the beam we can start seeing the background? The counters are located in IR2 or very near. They have not been identified precisely yet… Even though there is a huge number of files, not all aborts have been recorded. Sometimes the system is down or stopped. Sometimes (as a rule so far?) the system was only recording aborts during stable beam conditions (ie, not aborts during injection). A powerful possibility offered by the TR is to adapt its readings (the signals connected to its inputs) to the requests. Ie, it may not tell us where the background is coming from; but it can help test our models.
MDI meeting, Nov The data which have been looked for and at first are those of the aborts selected by Brian Petersen as “ aborts during injection”. Only 4 corresponding files have been found.
MDI meeting, Nov Data in the Transient Recorder for the same file (June26, 09:53:11) seen from the point of view of SVTRAD in the previous slide.
MDI meeting, Nov
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MDI meeting, Nov These plots are the same as in the previous page, BUT for the horizontal scale, with a much more limited range. One can distinguish the pattern of the injection. By properly identifying the hit counters, it is possible to distinguish HER from LER backgrounds.
MDI meeting, Nov
MDI meeting, Nov
MDI meeting, Nov Conclusions Abort files have been found, read, turned into ntuples and looked at. Abort events are clearly identified. Many variables which are recorded (p.ex. Beam Loss Monitors) do not appear to give any information so far: they could (with permission by SE, MP) be replaced by more interesting signals for special tests. I still need to identify precisely which counters are recorded. The units are not clear yet (they are not nice, digitized in ASCII form quantities, always the same through the exp.): they are in most cases Volts, we have to make sense of them.