XTRP track format

Each track found by the XFT trigger is sent by the XTRP extrapolation board to SVT and Level 2.
The format is sigle word packets, one track per packet.
XTRP tracks are received by the XTrp Fanout (XTF) board and sent to the 12 phi slices as two words packets (XTF tracks).

Word structure

24	23	22	21	20	19	18	17	16	15	14	13	12	11	10	9	8	7	6	5	4	3	2	1	0
HD	DS	0	1	eta	iso	Pt bin(7)							phi angle(12)

Data field assignement:

eta Set if outermost COT superlayer is missed

iso track isolation flag

Pt bin XFT Pt bin number [0-95]

phi bits 0-2=mini-phi, bits 3-11=wedge number

Notes:

in the first word the 5 in bits 18-20 is the layer number, fixed as 5 for XFT tracks as needed for proper working of AMchips.
From Richard Hughes: "The XFT Pt bins go from 0-95. The bins are arranged so that 0 is negative low Pt (-1.52 GeV/c) and 95 is positive low Pt (+1.52 GeV/c). The "infinite" momentum bins are 47 (negative) and 48 (positive). The low pt bins (0-15) and (80-95) are twice the size of the high Pt curvature bins (16-79)." See a table of Pt value for each bin center in table 1 of XTF Linker spesc (page 21).
The XTRP reports phi at SL6 radius (i.e. the 3rd COT axial superlayer), i.e. 105.575 cm. The mini-phi is the coordinate local to a wedge in the 0-7 range, and the wedge number ranges in 0-287 (24 in each of the 12 SVX/SVT wedges). Thus the phi angle is a continous variable in 0-2303.

BACK to the SVT data words format page

eta	Set if outermost COT superlayer is missed
iso	track isolation flag
Pt bin	XFT Pt bin number [0-95]
phi	bits 0-2=mini-phi, bits 3-11=wedge number