Modules

11 binary (half) modules (and 2x4 analog telescope planes) were read out simultaneously during the June test beam:

15. CG3 -- single sided, ABCD1.2 chips, 6cm detectors
1. SCAND1 --
2. -- empty slot
3. RLT9 -- irradiated to full dose at PS, only one plane read out
4. RLT5 -- RAL barrel module
5. RLK6 -- reference kept at fixed threshold and bias
6. K3112 -- KEK barrel module
7. K3103 -- idem
8. FR81 -- forward, kapton II module
9. FR152 -- forward, kapton III module
10. Anchor2 -- anchor, kept at fixed threshold, bias and rotation angle
11. Anchor3 -- idem

      Analysis

Threshold scans were done for various detector bias voltages, angles of incidence and magnetic field strength: a total of more than 300 runs. The runs are grouped in four Scans: Scan A has 0 angle/0 field, scan B has 0 angle/1.65 T field, scan C has max angle/1.65 T field, scan D has max angle/0 field. According to the alignment, the maximum angle is around 12 degrees and the first results seem to indicate that the sense of rotation is opposite to the Lorentz angle. These vague indications will be made more precise soon. For now, the angle will be referred to as maximum angle.

All data were taken in ANYHIT compression mode. For the efficiency we simulate LEVEL mode by selecting only the central time bin. A loose cut on the TDC is applied. If a hit is found within 300 microns of the extrapolated track, the event is considered efficient. The noise occupancy is calculated from hits in the non-central time bins, far from the track (1mm). Still, there is a considerable tail as a result of tracks that were not reconstructed correctly (one can see the beam profile in the noise hitmap)

The preliminary analysis assumes the target threshold value in fC of each run to be correct.

As data was taken in ANYHIT mode, hit information is available from the triggered clock cycle and the previous and next time bins. We can use this property of the FE chips to extend the time axis to get efficiency as a function of the charge deposition moment with respect to the sampling moment for a full 75 ns range. The width of the efficiency versus TDC distribution can be related to the shaper pulse length, which in turn depends on the charge collection time and thus the bias voltage.

     Results

The latest results from the June test beam were shown during the September SCT week. A PostScript document with the transparencies is available.

The earlier Preliminary results are still available - in PostScript format - for RLT9 (irradiated detectors), RLT5, KEK3103 and KEK3112.

• Files "[ModuleName]scurves.ps" contain the efficiency and noise occupancy as a function of threshold at high bias voltage (300 V on RLT9, 160 on the others) for four situations (permutations of 2 incidence angles and 2 magnetic field strenghts).
• Files "[ModuleName]scan[ScanID].ps" the "combined efficiency versus TDC of three time bins"-plots for all runs in the S-curves.
• Files "[ModuleName]multiplicity.ps" show the average cluster multiplicity of clusters within 500 um of the track, for the same runs.
• The perpendicular approach, looking at different bias voltages at a fixed threshold (of 1 fC), was also done for scan C and D: "[ModuleName]bias_summ.ps".
• And again, the individual "combined efficiency versus TDC of three time bins"-plots are available for all runs involved in the previous plot: "[ModuleName]bias_scan[ScanID].ps".

Test beam August 2000

Thisdocument summarizes the analysis of the August test beam so far. Also, I reprocessed the DSTs.

• Track finding parameters were optimised. This means the new DSTs will have more good ("1 track") events.
• Users will have a handle on track quality, as the chi squared of the track fit is included in the DST. This allows to select a sample of very precisely reconstructed tracks (down to 2 um) at a cost of statistics.
• Finally, a missing alignment (at -5 degree angle) has now been done.

Test beam August 2000 (at KEK)

Thisdocument summarizes the analysis of the August test beam so far.

Anyone is free to use these results, as long as it is mentioned they are preliminary.

Last update July 14, 2000
Marcel.Vos@ific.uv.es,