Geometry

Status:

• The tile and ribbon dimensions were obtained from the ACD engineers last summer. Joanne updated all dimensions to account for shrinkage at operating temperature.
• Overlap of top tiles
  Updated to go in the correct direction (thanks Joanne). Consequence was that the modeling of the ribbons on the top was modified causing the need to update some code in AcdRecon and AcdUtil.
• Curvature of the top tiles has been implemented in a more recent tag of xmlGeoDbs (thanks Joanne)
  This needs to be tested and the digitization and active distance calculations updated to accomodate the new volumes in the geometry.

To Do:

• Cross check the placement of the tiles and ribbons against the integration testing position maps.
  When will data be available? And in what form?
  It is fairly easy to dump the details of the ACD geometry from the simulation.

• Update Blanket/MMS
  Dave Thompson has provided the final numbers in a PDF file.
  Currently the blanket/MMS is simulated as a single layer of cooked up material. Do we desire a more accurate representation? The cost being multiple layers to propagate through in the simulation.

• Screws
  Typical tiles have four iron screws each, the bottom row large tiles have 20 (I think). Much work went into this before DC2. However, there were problems in how the volumes associated with the screws were handled by the simulation. Joanne has volunteered to address this again and basically start from scratch.

• Shingling
  Work on this has not been scheduled.

• No plans for modeling flexures, BEA, or updating the simulation of the support material.

Digitization

Any ACD detector with at least one PMT reaching zero suppression threshold, aka low threshold, aka 0.1 MIPs is stored on the TDS and ultimately in the output ROOT files - this collection forms the AcdDigiCol.
Please note that TriggerAlg was recently updated such that veto threshold (0.3 MIP default) is utilized in determining ACDLO in the GltWord.

Status

To Do:

• Ribbon Attenuation

• Fiber attenuation

• Utilize the AcdGeometrySvc throughout digitization and reconstruction for consistency.

Reconstruction

Considers all ACD detectors present in the AcdDigiCol, irrespective of the setting of the veto discriminator (hit map bit). This has been confirmed with Bill who explains that we are interested in background rejection at this level and desire to utilize all information available.

Status

New POCA and HIT classes.

To Do:

• Remove old DOCA and original Active Distance calculations and their ntuple entries.
  What does this mean? We will eliminate the following summary ntuple variables: AcdDoca, AcdDocaTileEnergy, AcdGammaDoca and their siblings located in the recon.root files.

• Update Ribbon Active Distance calculation

System Tests

Status

To Do: