Crystal Detector: geometry studies - starsim

First step is to remove BEMC module 88 and TOF tray 88 from geant geometry so we will have some space to position our Crystal Detector.

How-To:

1. Checkout fresh copy of the STAR geometry: cvs co pams/geometry
2. Apply patch for TOF: patch (patch < btofgeo2.g.patch from 'pams/geometry/btofgeo/' directory)
3. Apply patch for BEMC: patch (patch < calbgeo1.g.patch from 'pams/geometry/calbgeo/' directory)
4. Run starsim -W 1 and Issue detp geom Y2004; make geometry from starsim's prompt
5. Issue next; dcut cave z -10 10 10 0.035 0.035 from starsim's prompt
6. Issue next; dcut cave x 1 10 10 0.035 0.035 from starsim's prompt

Due to BEMC geometry description specifics, only Y2004 geometry tag allows us to remove single module (88 in our case). Please consider using detp geom Y2004; make geometry only - other tags won't work.

Result: clean space for insertion of the Crystal Detector superblock: see this image

Yulia's part: position three "supercubes" (9x20 crystals patches) inside the former BEMC module 88 space

Problem(?): twisted supercubes go off the limits of the BEMC module :( For details please see this image Also, this question could be studied with Gverify program, which is made exactly for the purpose of detecting overlapping volumes.

Result: done, three supercubes 9x20 with each crystal wrapped in mylar. Final geometry files could be found at: BEMC + CRD, TOF fixed

Due to uncertainties on how to position all three supercubes in STAR geometry, our first step would be the 'single supercube' geometry. Many important details could be checked using single supercube setup: background ('direct' hadron hits, SVT/TPC conversions, albedo from BEMC), even energy resolution.

Dmitry' part: former BEMC module 88 is now active volume (CsI), divided into eta/phi slices

Simple detector created in place of BEMC module 88: material CSI (defined in block, no such material available in starsim), hits contain eta/phi information.

How-To:

1. Apply this patch to calbgeo1.g
2. start starsim starsim -W 1
3. detp geom Y2004
4. make geometry
5. debug on
6. SWIT 2 3 switch to get tracks drawn on screen
7. gkine 1 1 0.5 0.5 -0.5 -0.5 -1.55 -1.55 single photon 0.5 GeV pointing to new Crystal Detector
8. trig 1 run photon, run!
9. gphits shows hits in Crystal Detector

Result: please see this image

Unsolved issue: how exactly PHI slices work in Geant for PCON shape? It seems that I can put in absolutely any(!) PHI range and it works(!), showing different PHI positions of the HITs

Active volume is not packed into alimunium cover yet (no mylar too)

Major task is to make Crystal Detector hits accessible via standard STAR Makers framework (so particle tracking also would be accessible). Therefore, we have to add our detector to pams/sim and St_geant_Maker. It has been done successfully: screenshot 1, screenshot 2

It was found that BFC chain crashes with segmentation violation rather frequently while converting .fzd file to .geant.root, so bug tracking ticket has been submitted (ticket) PS: ticket resolved, StTrsMaker should also be checked out and recompiled

Results: ready to do massive simulations with "three supercubes" geometry!