I haven't heard anyone talk about this yet, so here's what I have.
I processed the special calibration runs that were performed and have
generated ntuples for everyone to look at. As I suspected, the
calibrations do not do what I think people wanted them to do (simulate
lots of muons travelling at c) because things like cable and electronics
delays were not included in the calculation of the time offsets
requested. I doubt that these effects even can be included in the
simulation without a lot of effort.
This does not mean that the data won't tell us some of what we want to
know though. If you focus on just the results within a given pair of
scintillator tanks, you can look to see if the sense of the time is
correct when the order of the hits is reversed. Here is an example.
In the first case box 54 (1T01) is triggered before box 24 (1C08).
The reconstructed time difference reflects that this is relationship is
maintained.
+-------+----------------+----------------+----------------+
* ENTRY * IBOX0 * IBOX1 * TIME0-TIME1 *
+-------+----------------+----------------+----------------+
| 204 | 54.000 | 24.000 | -18.164 |
| 205 | 54.000 | 24.000 | -16.962 |
| 206 | 54.000 | 24.000 | -17.120 |
| 207 | 54.000 | 24.000 | -16.852 |
| 208 | 54.000 | 24.000 | -17.206 |
| 209 | 54.000 | 24.000 | -17.323 |
+-------+----------------+----------------+----------------+
In the second case the times are reversed with box 24 triggered before
box 54. Again, the time reconstruction keeps this relationship.
+-------+----------------+----------------+----------------+
* ENTRY * IBOX0 * IBOX1 * TIME0-TIME1 *
+-------+----------------+----------------+----------------+
| 211 | 24.000 | 54.000 | -32.655 |
| 212 | 24.000 | 54.000 | -31.568 |
| 213 | 24.000 | 54.000 | -31.712 |
| 214 | 24.000 | 54.000 | -31.521 |
| 215 | 24.000 | 54.000 | -31.781 |
| 216 | 24.000 | 54.000 | -31.699 |
+-------+----------------+----------------+----------------+
If people want to look closely at the results of these calibration runs,
the ntuple files can be found at DISK$MACRO:[MACROUSA.OKADA]902XX.NTP
and the ntuples have the entries:
run = run number
event = event number
box0 = initial calib box fired (remapped to mod(CALMOD box,100))
box1 = delayed calib box fired (remapped to mod(CALMOD box,100))
smbit = supermodule bit
delay = programmed delay
ibox0 = ERP box matching box0 in the data
ibox1 = ERP box matching box1 in the data
time0 = mean time for ibox0
time1 = mean time for ibox1
tdcz0 = position for ibox0
tdcz1 = position for ibox1
x0 |
y0 |
z0 | = 3D coordinates for the hits
x1 |
y1 |
z1 |
runevt = 0
Note: the box recorded in the calibration pattern register corresponds
to the position within the ERP crate. This is not the CALMOD box, nor
is it the ERP hardware address. In order to get the desired information
I had to map from one set of numbers to the other.
Colin