# Presentation: 078065

## Particle ID Software

- Steve Kahn
- Brookhaven National Lab
- 27 March 2003

## 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 .

## 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*

## 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.

## TOF I Station

- TOF I is located after 1st diffuser where beam comes into hall.
- This at  –15 meters from center of cooling cells.
- TOF I is 1212 cm2 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 cm3.
- Using Bicron BC-420 fast Scintillator.
- Use Hamamatsu R4998 Phototubes on each end.
- 0.7 ns rise time, 160 ps transit time jitter

## 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 cm2 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 cm3.
- 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.

## 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.

## Slide 8

## Slide 9

## Time Resolution:  trecon-ttrue

- TOF 1: =35 ps

- TOF 2: =108 ps

- TOF 3: =108 ps

## Transit Time from TOF1 to TOF<number>

- ~20 tracks consistent w/ electrons from mu decay

## 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 cm3 aerogel radiator segmented into an array of 1010 cm2 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.

## 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.

## Downstream Cherenkov System

- Developed by G. Grégoire of Université de Louvain.
- The radiator is aerogel with nrefraction=1.02 and covers 9090 cm2 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106 needed for low Č light yield in aerogel.
- 24 cm PMT photocathode radius.

## Spatial distributions

- Beam spot ~300 mm diam. ~ size of the radiator

- Numerical aperture  (f-number)  = ~ 1.5

- x

- y

******xz**

******yz**

- Divergence  **** ~ 20°

- Slide from Gh. Grégoire
- July 9, 02 Presentation

## 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

## 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

## 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.

## Particle ID Package Status

| Package | Geometry | Digitization | Reconstruction | Analysis |
| --- | --- | --- | --- | --- |
| TOF | √ | √ | √ | ? |
| Orig Č | √ | √ |  |  |
| Upstream Č |  |  |  |  |
| Downstream Č | √ | √ |  |  |
| EM Cal | √ | √ |  |  |