DRAGON Meeting Minutes 6th Jan 2004 Present: LB, AO, JS, ML, JR, JD, DO, DH, MP, GR, BD, CR, MT Recorder: CR 1. Last Meetings Minutes: DH pointed out that he was quoted as saying that something should be “flushed out” when he actually said “fleshed out”!! 2. New Group Members: JD introduced Goertz Ruprecht, our new Post-Doc from Berlin, who will be working with DRAGON/TUDA over the next year, and also our new co-op student Josh Slater 3. Facility: The new turbo pump has still to be installed on the downstream side of the target (low pressure end). It is expected this will be completed by the end of the week, although there was some discussion of whether water cooling or air cooling is required. DO to attend to this. The Quadrupole Mass Spectrometer has been recovered from the Dipole and is available for other uses. JD noted that tools belonging to DRAGON should be securely locked up after use – too many items have been going missing by the mystery TRIUMF poltergeist who seems to have stolen all of TUDA’s tools also!! 4. Detector Testing: ML has to complete tests of MCP for his thesis. He will eventually require access to HI beams, therefore Beamtime Requests should take this into account. The idea is to show the TOF capability of the MCP. What beam is used is as yet undecided – 12C is easy to make, but a high Z beam like Sodium would be desirable because large pulse heights (from larger dE/dx) make measurement easier. The PGAC should be resurrected soon, for use in conjunction with the ion-chamber. Previous tests showed signals but some kind of acceptance problem. Someone should be assigned to this project (Author’s note: I am interested! ) 5. Electronics/DAQ JR has prepared a document (see attached), explaining the function and layout of the DRAGON electronics and acquisition system, from the pulse shaping and logic circuits to the CAMAC readout. He will also be preparing documentation on the software side. MP will put these documents in electronic format (and on to Web). The purpose of the documentation is so that future generations of Dragoneers can maintain or modify the system with minimum of fuss, whilst remembering to heed JR’s trusted adage: “Open the door – don’t work no more!” (The door to the electronics hardware should remain shut and be tampered with only in emergencies or periods of modification or repair). The diagram which JR provided is in “real estate” format, i.e. the layout is not in terms of logical function of the NIM and CAMAC units but instead reflects the physical layout of the electronics modules within the crates. Hardware aspects that may need to be routinely changed or checked before each run are: The elastic monitor prescaler (currently set to 1, but which can be set to divide by powers of 2 if the elastic rate is swamping everything else); The elastic monitor pulser (currently set to around 1 Hz, which is useful in determining deadtime and for diagnostical purposes); the elastic monitor gain; the gamma-triggered pulser (which is used to check timing resolution, and is not used in a standard run). It should be noted that the Ion Chamber and the PPAC/PGAC are not included in the diagram. DH has a drawing of the IC electronics. Many of the electronics modules (ADC’s logic units etc.) were made by LeCroy, who are no longer in business, therefore no replacement for these exists except what may be available on site (although there may be one company who repairs these modules). JR should add instructions to the documentation on how to load the correct ODB file for an experiment. There was a discussion on whether we take the RF from the low-beta buncher or from the RFQ pre-buncher. This should be checked and noted in the documentation also. Lastly, JR described the CAMAC outputs, which are useful for debugging purposes when events do not appear in the software. Refer to the documentation for details. 6. Beam Requests: On-line beams will be available from March 17th, but stable (OLIS) beams will be available from mid-February. Several options are available for requests this period (until September): UG wants to run radioactive Ne19; 26Al is in the pipeline. Dave Jenkins wants to run more 12C+12C Lothar’s 12C(a,g)16O should continue. (at 1.75 MeV/u) For the last experiment, LB wants tests of the DRAGON GEANT simulation made, i.e. comparisons between experiment and simulation, in order to be sure that be can trust the predictive power of GEANT. Also it was mentioned that the ability of the operators to get a good tune through the gas target may be a vital parameter in the success of these runs. We may have to repeat the quad variation studies to explore the tuning properties of DRAGON for this experiment. The wild variation of yield for runs at the same energy was also discussed. Is this a beam tune dependent property? Again, we need to be able to trust the simulation. DH notes that there are new ISAC operators who need to be trained and will be using 5 –hour training periods which will eat into the available beam time. The beam requests are due in on Jan 12th, so JD will make up a priority list for selected beams. It is up to the spokespersons to submit individual requests however. Minimum useful intensities should be specified for these beams. Other beams were suggested such as 13N and our old friend 21Na. 7. Latest 21Na(p,g)22Mg paper: MT is finishing the analysis of the higher energy resonances by investigating Lorentzian fits to the excitation functions using PHYSICA. He requires to investigate Sabine Engel’s methods and Alan Chen’s methods to compare how they fitted the data. Once this analysis is completed, DRAGON will submit the paper containing much of the work done last year on this reaction. 8. Next weeks meeting: …will be held on Thursday instead of Tuesday.