1. Geometry of the ACD Beam Test at CERN (2002) Tsunefumi Mizuno mizuno@SLAC.Stanford.EDU Overview of the Setup: p.2 ACD tile configuration: pp.3-4 Sn Calorimeter: p.5 Pb Calorimeter: pp.6-8, p.11 Fe Calorimeter: pp. 9-10 Al support: pp. 12-13 Digital photos and G4 programs can be taken from the following URL: http://www.slac.stanford.edu/~mizuno/GLAST/CernBeamTest/index.html

2. Overview of the Setup Trigger Scint 3 20cm x 20cm x 1 cm with a hole (1cm diameter) Trigger Scint 1 1.5cm x 1.5cm x 0.5cm Trigger Scint 4 10cm x 10cm x 1 cm ACD 54cm x 24cm x 1cm Calorimeter Absorber (20cm x 20cm) We adjusted thickness and material Scintillators (20cm x 20cm). Called Preshower Scintillator (left), S1 (middle) and S2 (right) 20-80cm (in most cases, 45cm) Note: In run #01-10, we adjusted beam position in ACD to calibrate each tile. After that, we fixed beam position at 1cm (see the Figure above). In run #44-47, we removed Preshower Scintillator and S1 (run without Calorimeter gap). For more detail of each run, please see official logbook (Alex’s notebook). 47cm 1cm 53cm Beam Trigger Scint 2 1cm x 1cm x 1cm

3. ACD tile configuration (1) The photo shown above was taken from the Beam Side. The Calorimeter tiles were numbered from 2 (leftmost seen from CAL) to 9 (rightmost seen from CAL). Centers of tiles were marked as 3 (tile #9), 9, 15, 21, 27.5, 35, 42.5 and 50.5 (tile#2). These numbers could indicate the center position of each tile in cm. BeamTest_012.jpg

4. ACD tile configuration (2) The dimension shown above is taken from the document written by Alex (ACD beam test at CERN SPS in 2002) and are used in the current G4 simulator. The widths of tiles are somewhat inconsistent with numbers marked in tiles (see the photo in previous page). Alex, do you know which one we should use? #2 #3#4#5#6#7#8#9 24cm 8cm x 3 6cm x 5 (Seen from the Beam side)

5. Configuration of the Calorimeter: Sn 4x(1/8inch)12x(1/8inch) 16x(1/8inch) spacer (2cm) spacer (1.5cm) This calorimeter was used in run #16-29. BeamTest_010.jpg

6. Configuration of the Calorimeter: 20X 0 Pb (1) 2x(1/8inch) spacer and PS 1inch spacer and S1 4x(1/8inch) spacer and S2 2x1inch gap This calorimeter was used in run #30-32, 41 and 42. BeamTest_028.jpg

7. Configuration of the Calorimeter: 20X 0 Pb (2) Positions of lead layers were recorded as above. We may need to simplify the configuration and implement it in the simulator.

8. Configuration of the Calorimeter: Pb 10X 0 : run#33, 34, 39, 40 removed 2X(1inch) 30X 0 : run#35-38, 5X(1inch) instead of 2X(1inch)

9. Configuration of the Calorimeter: Fe (1) This calorimeter was used in run #43, 48 and 49 1inch spacer and PS 2X(1/2inch) 2X(1/4inch) spacer and S1 S2 BeamTest_042.jpg

10. Configuration of the Calorimeter: Fe (2) As shown above, iron layers were stacked tightly. We only need to take gaps between Fe layers at spacer into account. thickness of the scintillator 1.6cm gap between Fe layers

11. Configuration of the Calorimeter: Pb without gap BeamTest_039.jpg 1inch S2 This calorimeter was used in run #44-47

12. Configuration of ACD Al support (1) Al support structures covered the part of ACD tiles as above. viewed from the CAL side BeamTest_013.jpg

13. Configuration of ACD Al support (2) Al support structures covered the part of ACD tiles as above. viewed from the CAL side 6mm thickness Distance was measured as 33.5cm. A little bit larger? (8+8+6+6+4.5=32.5cm)