HCAL Segmentation and Readout Considerations

The HCAL consists of 4 parts:  HB, HE, HO, and HF.  The following is a rapidity (h) view of the detector but does not include HF:

The HTR cards will need to collect HCAL towers and form "trigger primitives" (TPG) to send to Level 1.  As you can see, the number of towers to be added together is a function of rapidity.   The TPGs will need to present to the trigger the amount of energy in a tower of Dh=.087 and Df=5 degrees for most towers.  The following picture is old, since it was made before the 1st layer (green) was added to the second layer to form a single layer.  But it illustrates the geometry of the wedge:

An added complication is that in the HE,  starting at h=21, the Df bite increases to 10 degrees. This means we will have to take add up the energy in relevant towers, and divide by 2 to send the right TPG to the L1 trigger.   Note that the following picture is inaccurate as far as depth segmentation is concerned but otherwise ok:

This is an old xls file that shows the ganging vs. eta.

Using this file, we can form the following table of channels vs. TPG for the HB and HE.  Note that the HO is not involved in the Level 1 trigger.
 
  h 
HCAL
Towers per f=2p
 Longitudingal Channels 
Number of TPG
1
HB
72
1
72
2
HB
72
1
72
3
HB
72
1
72
4
HB
72
1
72
5
HB
72
1
72
6
HB
72
1
72
7
HB
72
1
72
8
HB
72
1
72
9
HB
72
1
72
10
HB
72
1
72
11
HB
72
1
72
12
HB
72
1
72
13
HB
72
1
72
14
HB
72
1
72
15
HB
72
3
72
16
  HB+HE 
72
4
72
17
HE
72
2
72
18
HE
72
1
72
19
HE
72
1
72
20
HE
72
1
72
21
HE
36
1
72
22
HE
36
1
72
23
HE
36
1
72
24
HE
36
1
72
25
HE
36
2
72
26
HE
36
2
72
27
HE
36
5
72
28
HE
36
5
72
29
HE
36
5
72

eta    number in tpg sum     number per phi         number of tpg
1            1                                72                                72
2            1                                72                                72
3            1                                72                                72
4            1                                72                                72
5            1                                72                                72
6            1                                72                                72
7            1                                72                                72
8            1                                72                                72
9            1                                72                                72
10            1                                72                                72
11            1                                72                                72
12            1                                72                                72
13            1                                72                                72
14            1                                72                                72
15            3                                72                                72
16            4                                72                                72
17
18
19
20
21
22
23
24
25
26
27
28