1. Stephen KahnParticle ID Software Mice Collaboration Meeting Page 1 Particle ID Software Steve Kahn Brookhaven National Lab 27 March 2003

2. Stephen KahnParticle ID Software Mice Collaboration Meeting Page 2 Particle Identification Systems Time-of-Flight system: –Can separate  from  in the incoming beam by transit time between two upstream TOF stations. –Can separate e from  decay based on transit time. Cherenkov Detector Systems: –Upstream system Supplied by University of Mississippi –Downstream system Supplied by Université de Louvain. EM calorimeter: –Downstream to separate electromagnetic energy (e,  ) from .

3. Stephen KahnParticle ID Software Mice Collaboration Meeting Page 3 Glossary of Terms Used in MICE Software Simulation: –Tracking through cooling and detector channels. –Hits produced in active detectors contain the true track parameters. –Output file is called Sim.out Digitization: –A response to a track traversing a detector can be recorded. This recording is referred to as a digitization. It can be – ADC counts representing the pulse height in a phototube. –TDC counts representing a time measurement of the track traversing the detector. –These digitizations are not the true track variables. They represent how the detector sees the track. –The digitization output file is called Dig.out

4. Stephen KahnParticle ID Software Mice Collaboration Meeting Page 4 Glossary, continued. Reconstruction: –Although the detector digitizations contain all the information that can be known about the, they are not directly realizable as kinematic variables. –The reconstruction process translates the digits into kinematic variables as best it can. These reconstructed variables will differ from the original simulated measurements because of detector measurement errors. –The output file of this process we call rec.out The original true variables are carried along for comparison, however they will not be available for the experiment. Analysis: –Plotting detector simulated data. – Comparing reconstructed variables to true variables. –Determining the particle ID (is this a muon?) –Calculating the emittance.

5. Stephen KahnParticle ID Software Mice Collaboration Meeting Page 5 TOF I Station TOF I is located after 1 st diffuser where beam comes into hall. –This at –15 meters from center of cooling cells. –TOF I is 12  12 cm 2 in size. –TOF I is composed of two planes oriented in X and Y respectively Each plane is segmented into two slabs with phototubes on each end. Each slab is 12  6  2.5 cm 3. Using Bicron BC-420 fast Scintillator. –Use Hamamatsu R4998 Phototubes on each end. 0.7 ns rise time, 160 ps transit time jitter

6. Stephen KahnParticle ID Software Mice Collaboration Meeting Page 6 TOF II AND TOF III Stations TOF II (TOF III) is located before (after) the upstream (downstream) measurement solenoid. –This is at –5.544 meters from the center of the cooling cells. –TOF II, III are 40  40 cm 2 in size. –TOF II, III are composed of a single Y oriented plane. The plane is segmented into 8 slabs. Each slab is 40  6  2.5 cm 3. –There is ~1 cm overlap at the edges of the slabs to allow cross- calibration. Bicron BC-404 Scintillator is used for these stations since it has a longer attenuation length than the BC-420 used in station I. – =1.7 meters.

7. Stephen KahnParticle ID Software Mice Collaboration Meeting Page 7 TOF II and III continued The choice of phototube to use for the TOF II and TOF III stations is complicated by the presence of fringing magnetic field from the measurement solenoids. –The field situation is shown in the following transparencies. –The fast phototube used for TOF I (R4998) does not tolerate much magnetic field. The choices are Shield the fast Hamamatsu R4998 phototubes. Use the Hamamatsu R5505 fine mesh phototube which can handle fields up to ~1 Tesla.

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10. Stephen KahnParticle ID Software Mice Collaboration Meeting Page 10 Time Resolution: t recon -t true TOF 1:  =35 ps TOF 2:  =108 ps TOF 3:  =108 ps

11. Stephen KahnParticle ID Software Mice Collaboration Meeting Page 11 Transit Time from TOF1 to TOF11 ~20 tracks consistent w/ electrons from mu decay

12. Stephen KahnParticle ID Software Mice Collaboration Meeting Page 12 Original Mississippi Downstream Cherenkov The original downstream Č system that was in the Dec ’02 version of the simulation was based on a 100  100  15 cm 3 aerogel radiator segmented into an array of 10  10 cm 2 tiles, each with 2 PMT for light collection. –The geometry of this system was implemented in Geant4. –There was a detector response coded for the PMTs, but it does not appear to have a Č response. Geant, itself, can create and track Č photons.

13. Stephen KahnParticle ID Software Mice Collaboration Meeting Page 13 Upstream Cherenkov Detector The upstream Cherenkov detector will be based on the Mississippi design. It is likely to be simpler than the original. At this point it is not in the current MICE Geant package. –It should be straight forward to modify the original code from Romulus Godang to put it in.

14. Stephen KahnParticle ID Software Mice Collaboration Meeting Page 14 Downstream Cherenkov System Developed by G. Grégoire of Université de Louvain. The radiator is aerogel with n refraction =1.02 and covers 90  90 cm 2 and has a thickness of 10 cm. Light is reflected by  45º mirrors into 20  diameter Hamamatsu R3600-02 PMTs. (Super K kind). –Large gain 3  10 6 needed for low Č light yield in aerogel. –24 cm PMT photocathode radius.

15. Stephen KahnParticle ID Software Mice Collaboration Meeting Page 15 Spatial distributions Beam spot ~300 mm diam. ~ size of the radiator Numerical aperture (f-number) = ~ 1.5 x y  xz yzyz Divergence  ~ 20° Slide from Gh. Grégoire July 9, 02 Presentation

16. Stephen KahnParticle ID Software Mice Collaboration Meeting Page 16 Angular and energy distributions Angle with respect to beam axis Kinetic energy distribution It is not obvious (to me) to separate e-  on calorimetric principles at such low electron energies! Electrons have very low energies ( E< m  ) Slide from Gh. Grégoire July 9, 02 Presentation

17. Stephen KahnParticle ID Software Mice Collaboration Meeting Page 17 Current Status of the Downstream Č Geant Software A model of the Louvain Č detector has been coded. –DetModel classes: CKOV2Tracker CKOVHit and CKOVSD slightly modified, but are common with Upstream Č –Config classes: CKOV2TrackerGeom –Interface classes: CKOV2HitBank Inherits from CKOVHitBank –DetResp classes: CKOV2Digits –Calib classes: CKOV2DigitParams

18. Stephen KahnParticle ID Software Mice Collaboration Meeting Page 18 Current Status of Č Software The CKOV2Digit does try to simulate what each of the 4 PMTs would see from the Č process. –There is no signal for imaginary Č angles. µ’s and e’s will look different. This new downstream Č classes exists on my computer. –They are not yet in CVS (Yagmur says that means they do not exist) –They compile and link. They are being verified.

19. Stephen KahnParticle ID Software Mice Collaboration Meeting Page 19 Particle ID Package Status PackageGeometryDigitizationReconstructionAnalysis TOF √√√? Orig Č √√ Upstream Č Downstream Č √√ EM Cal √√