1. Low Momentum dE/dx Testbeam H.P. 7/24/98

2. Goals for Spectrometer are based on tracking and PID –Multiparticle correlation –production of particle species –Pt distributions all that this emphasis on low p t what do we need? –Tracking -> based on the pad signals –PID in high momentum range ->based on dE/dx –PID in low momentum & stopping range-> based on dE/x

3. Range out(in 7 planes) 55 MeV/c  135 MeV/c K dE/dx650 MeV/c  /K 1000 MeV/c K/p TOF1150 MeV/c  /K (y-dep) 1900 MeV/c K/p The high p t range Good separation requires good understanding of the detector algorithms that are tuned to OUR detector

4. The low P t range-stopping p,K,  The problems: few dE/dx measurements/particle no magnetic field in first 6 planes little help from TOF Need to rely on dE/dx measurement in range where very little is known about the response of silicon detectors

5. Our dE/dx range...

6. Spectrometer Acceptance

7. We are well equipped for dE/dx... We achieved good signal/noise-> allows a dE/dx measurement with good precision We studied detector properties of Type 1 and 5 with source and high momentum testbeam (little crosstalk, good signal uniformity) We designed and implemented a calibration system-> measure and monitor the electronics gain We have fully working final modules ready for tests

8. The proposed dE/dx testbeam measure dE/dx in silicon for >50MeV/pions and >200MeV kaon and proton measure the signal response for stopping ,K,p ? A proposed setup identical to first 4 spectrometer planes: 4 Type 1 modules TOF scintilators for PID This testbeam can be done in collaboration with the Insitute of High Energy Physics /Vienna

9. The currently most promising beamline (AGS E913) Steve contacted Brad Tippens (E913 spokesperson) -> we are invited to run behind E913 during September The beam line can supply , K, eventually proton has full TOF measurement in place, where we can get TOF measurement initial beam  p/p = +-4%, with TOF good to 4-5MeV sufficient space available for detectors and electronics they plan to vary energies in their run furing September we need to run their energies (-> close coordination) need to confirm possible energies/rates/composition

10. A possible setup... E913 TOF start TOF stop (963cm) 1.9m E913 present energies pion >200MeV/c kaon>500MeV/c protons>? this is the range where we claim to be able to separate  /K

11. Sharing of responsibilities The HEPHY/Vienna takes main responsibility for the DAQ they are currently building a 12-bit 4 channel VME board with VA control dedicated for this test they can supply a TDC in necessary they can supply limited workshop time for mechanical parts they will send 2 person for 2 weeks for the beam tests and later plan to work on analysis with 1 student in Vienna Our responsibility: detector and beam line preparation prepare, test and calibrate 4 type 1 modules prepare beam line (detector support& cooling, cables, 1 VME crate, 1 PC) send 2 person for preparation and data taking participate in analysis (I would assume…)