From: Ian Bearden (bearden@nbi.dk)
Date: Mon May 19 2003 - 07:12:26 EDT
Hi Ramiro, I have been looking for the last measurements, but I guess in the wrong place. I looked here: http://www.sdcc.bnl.gov/brahms/private/detectors.html under "magnets" in FS. Where can we find the translation? Cheers, Ian On mandag, maj 12, 2003, at 19:34 Europe/Copenhagen, Ramiro Debbe wrote: > If you are using the permanent Hall probe readouts without any further > change you will not have the correct field value. > The Hall probes are located right on the magnet poles and most on the > time two to three gap heights into the magnet gap. > At those locations they are sensing the saturation in the iron. That > must be most of the deviation one can see in the plots. > The value of By at high field deviates from a linear function of the > current because of saturation and hopefully that is well described by > the parametrisation in BRAT. > > The last measurements I did for all our magnets should give you the > translation between permanent Hall probe readings and the value of the > field in the middle of the gaps. For D4 I have two sets of > measurements, one with the Hall probe in the old > position, and a second one where the Hall probe was moved deeper into > the magnet gap. (this last settings can be used for the dA and this > last pp run and all future runs) > > Ramiro > > > On Monday, May 12, 2003, at 12:21 PM, Claus O. E. Jorgensen wrote: > >> >> Hi, >> >> I'm currently looking at the high field Au+Au runs and I'm having some >> trouble at the edges of the acceptance - the data is not right on the >> MC so I started looking at the magnetic field. Is it correct that we >> still use the (2nd order) parametrization of the field? >> >> I've compared the field I get from BRAT and what has been measured >> (By) >> with the Hall probe and there is a small discrepancy which I guess >> would >> effect the high field data the most. Have a look: >> >> www.nbi.dk/~ekman/fieldVsCurrent.gif >> >> Putting the numbers directly in BrMagnetVolume would be very easy, >> but I >> guess that's not good enough. Do we want to store this information in >> the >> DB? And what does it take? I think it's pretty important if we want to >> make a good analysis of the high field data... >> >> Cheers, >> >> Claus >> >> +------------------------------------------------------------+ >> | Claus E. Jørgensen Phone : (+45) 33 32 49 49 | >> | Cand. Scient. (M. Sc.) Cell : (+45) 27 29 49 49 | >> | Office : (+45) 35 32 54 04 | >> | Niels Bohr Institute, Ta-2, Fax : (+45) 35 32 50 16 | >> | Blegdamsvej 17, DK-2100, E-mail : ekman@nbi.dk | >> | University of Copenhagen Home : www.nbi.dk/~ekman/ | >> +------------------------------------------------------------+ >> > > >
This archive was generated by hypermail 2.1.5 : Mon May 19 2003 - 07:13:28 EDT