March 31, Status of the TOF, Ckov and Virtual Detector Packages in G4Mice Steve Kahn Brookhaven National Laboratory Mice Collaboration Meeting March 31, 2004

S. Kahn Status of TOF, Ckov and Virtual Detectors Page 2 Changes in the Both the Upstream and Downstream Particle ID Detectors Recently there have been changes made to both the upstream and downstream particle ID detectors. –I will summarize the changes that have been made and those that are yet to be made. These include positioning and segmentation changes to the upstream time-of-flight detectors. Positioning changes of the upstream Cherenkov chamber. Positioning and dimensional changes to the downstream Cherenkov. –I would also like to discuss future plans for improvements. Also I will describe some of the difficulties encountered in the use of the virtual detector

March 31, 2004S. Kahn Status of TOF, Ckov and Virtual Detectors Page 3

March 31, 2004S. Kahn Status of TOF, Ckov and Virtual Detectors Page 4 The Time-of-Flight System : Tof0 The Tof0 plane is now situated in the first of the beam line final focusing triplets. –Tof0 is situated between Q4 and Q5 triplet quads. This station will see a high rate and consequently will require a high resolution PMT such as R4998. The Tof0 plane is situated at where the magnetic field is (hopefully) small. The size of the Tof0 plane has been increased to an active area of 24 cm  24 cm. There are now X, Y planes each with six 4 cm slabs. There is no overlap of adjacent slabs. The dE/dx should now be uniform across the plane.

March 31, 2004S. Kahn Status of TOF, Ckov and Virtual Detectors Page 5 The Tof1 Plane The Tof1 plane is now situated in the second of the beam line final focus triplets. –Tof1 is situated between Q8 and Q9. This should also be in a low field area. –Placing the focusing elements between the Tof planes should improve the rate into the cooling channel and consequently increase the rate at Tof1. We are likely to use the high resolution PMT since we are concerned with the high rate and are not worried about large fringe fields from adjacent magnets. We now have X, Y planes at Tof1 We have 48  48 cm planes with with eight 6 cm slabs.

March 31, 2004S. Kahn Status of TOF, Ckov and Virtual Detectors Page 6 Tof 2 Downstream Detector The Tof2 downstream detector has the same geometry as Tof1 however it uses the R7761 fine mesh PMT since it is in a higher magnetic field. Although the geometry of Tof1 and Tof2 are the same the detector response is different since they use different PMTs. –The different detector responses still needs to be coded.

March 31, 2004S. Kahn Status of TOF, Ckov and Virtual Detectors Page 7 Upstream Ckov The upstream Ckov is now situated between the two beam line final focus triplets. It is midway between Q6 and Q7. –This should be in a field free area. –The position of Ckov1 has been updated in the dataCards.

March 31, 2004S. Kahn Status of TOF, Ckov and Virtual Detectors Page 8 Downstream Cherenkov Detector The downstream Ckov detector geometry has not yet been revised. –I need to verify if dimensions have changed. –I need to revise the geometry to the 8 PMT picture. Currently I have a 4 PMT description. I would like to implement a full cherenkov photon tracking version for Ckov2. –Currently the Ckov2 response is the intersection of the cherenkov cone with the PMT acceptance.

March 31, 2004S. Kahn Status of TOF, Ckov and Virtual Detectors Page 9 Virtual Detector Status The virtual detector is a scoring volume that can be placed along the beam line for the purpose of providing theoretical variables for analysis especially for the calculation of emittances, but not limited to that. –An alternate version referred to as a Special Virtual volume can be attached (a daughter volume of) coils and absorbers for the purpose of investigating energy deposit. There are currently limitations to how the virtual volumes can be used. –The current scheme only allows the virtual detector to be placed as the daughter of the overall detector mother volume. It cannot be easily placed inside other detectors such as the SciFi. –This would be of value to the SciFi particularly since there could be a direct comparison of the reconstructed track variables to the corresponding theoretical variables. –We have attempted to address this by specifically coding a call to a virtual detector in the SciFiTracker volume. There are however problems in getting Geant to actually enter this volume. –This problem has not been solved as of this moment.

March 31, 2004S. Kahn Status of TOF, Ckov and Virtual Detectors Page 10 Status Summary Tof Detectors –Geometry/Segmentation changes to bring DetModel up to date ☺☺☺ –Need to correct detector response for Tof1 using different PMT from Tof2. Should be straight forward.☺☺ Upstream Ckov –Position updated. ☺☺☺ Downstream Ckov –Verify positions and dimensions correspond to current PID picture. ☺☺ –Update to 8 PMTs. ☺ –Add facility to track č photons. ☺ Virtual Detectors. –Fix problem with using virtual detectors with SciFi.  –Fix problem with energy deposit in front part of absorbers. Probably similar to SciFi problem. 