Summary of DELANA processings in 1996 and 1997

DELANA processings in 1996 and 1997

Introduction

Below is a summary of the main Delana processings made during 1996 and 1997.
Early incomplete processings of the data for a given year are mentioned only briefly.
No attempt is made to document the numerous processings of calibration data (STP selected events and Z0 data) use to prepare full reprocessings or to test code developments.

It helps to distinguish three versions of the tracking code used in DELANA during 1996 and 1997:

The old barrel and forward tracking (OLD) using the TPC as pivot in the barrel. This was essentially the tracking code as used for all LEP100 processings before 92E, 93D, 94C, and 95D.
New Barrel Tracking (NBT) using three algorithms :
- The old TPC pivot search
- ID+VD search
- TPC+VD search
plus a re-writing of the forward track search and extensive updates to the fitting and ambiguity resolution code. This was the code developed for the reprocessing of LEP100 data.
New Forward Tracking (NFT) updating NBT with new algorithms in the forward region. Production runs using this version include the VFT in the tracks. Also in this version the TER derived from the drift time readout of the Straw tubes replaces the TER derived, as for the old ID trigger layers, from the hit pattern on the wires.

Reprocessings of LEP100 data.

The processings of the LEP100 data listed below, using the NBT version, the best knowledge of detector calibrations and alignment, and with scalings of detector error matrices inside Delana, replace all previous processings.

94C (NBT) processed 9 Sep 1996 ---> 5 Nov 1996
95D (NBT) processed 9 Apr 1997 ---> 24 Apr 1997
93D (NBT) processed 15 May 1997 ---> 26 May 1997
92E (NBT) processed 4 Jun 1997 ---> 21 Jun 1997

Processings of 96 data.

During the data taking of 96, a new processing of the data was started whenever there was a significant update of the detector calibration or alignment. This resulted in several incomplete processings, the last of which was:

96Z_D (OLD) proc 9 Aug 1996 ---> 19 Aug 1996 (1st period of Z0 data)
96H_D (OLD) proc 9 Aug 1996 ---> 19 Aug 1996 (161 GeV data)

The first complete processing of 96 data is the E processing, still using the OLD version of the code, starting in September and running until the end of the data taking. This also used an early version of the VD alignment and other detector calibrations.

96H _E (OLD) proc 11 Sep 1996 ---> 21 Sep 1996 (161 GeV data)
96Z _E (OLD) proc 23 Sep 1996 ---> 25 Sep 1996 (1st period of Z0 data)
96Z2_E (OLD) proc 14 Oct 1996 ---> 21 Nov 1996 (Z0 data from 2nd period)
96H2_E (OLD) proc 19 Oct 1996 ---> 21 Nov 1996 (172 GeV data)

After the LEP100 reprocessings (see above) the 96 data were rerun (96F) using the NBT version of the code.

96Z_F (NBT) proc 2 Jul 1997 ---> 3 Jul 1997 (Complete 96 Z0 sample)
96H1_F (NBT) proc 9 Jul 1997 ---> 14 Jul 1997 (161 GeV data)
96H2_F (NBT) proc 14 Jul 1997 ---> 17 Jul 1997 (172 GeV data)

The main updates for this F processing compared with the E processing were:

use of the new barrel tracking.
new VD internal alignment.
VD error parametrisation for the new longer detector, cluster fixing and update of signal/noise cuts.
update of the code for association of VD z hits.
1st estimate of TPC distortion corrections.
new momentum dependent version of the ID fix. Improved ID bunch tagging.
better description of the material near the vertex.
updated global alignment of barrel and forward chambers.
scaling of detector error matrices
calibration updates for several other detectors (TOF,FCA,FCB,OD,RICH,STIC..)

Processings of 97 data.

As in 96, several early reprocessings were driven by updates in detector calibrations and alignment. The C processing was started 8 Aug and continued through the '130 GeV' data taking until 20 Oct. It thus represents the only processing of the '130 GeV' data made in 97, but is incomplete as regards the 183 GeV data.

97Z _C (NBT) proc 8 Aug 1997 ---> 12 Aug 1997 (Z0 sample)
97H _C (NBT) proc 13 Aug 1997 ---> 20 Oct 1997 (183 GeV data)
97P _C (NBT) proc 4 Oct 1997 ---> 10 Oct 1997 (130 GeV data)
97PVFT_C (NFT) proc 4 Oct 1997 ---> 10 Oct 1997 (simultaneous processing of 130 GeV data as test of NFT version)

Note that early runs of the C processing (--> 14 Aug) did not use the correct calibration for the STIC energy, which was corrected for the remainder of the processing. Full details and corrections have been given in the news. Test processings using the NFT version of the code were also made :

Z0 data : 21 Aug 1997
DAFNE tagged rare events : two batches 17 Sep 1997 and 29 Sep 1997

The 97D version of Delana became available 13 Oct 1997.
Main updates compared to the 97C processing were as follows:

FCBANA updates to improve reconstruction of TER in side with missing planes.
Correction for the STIC energy calibration at the start of data taking. (missing from the early runs in 97C).
TPC distortions for 97 included (determined from hadronic tracks) plus updates to T0.
0th order energy calibration for the HPC. Calibrated ring by ring.
EMF energy calibration.
RICH calibration of drift velocity and correction for shorts.
T0 adjustment for OD and Straws.
New global alignment including first full alignment of the forward region.
VFT global alignment and mapping of hot pixels.

Note that VFT was written to the DST in 97D but not included in the tracks.
With this D version the following processings were performed:

97_Y (NBT) proc 14 Oct 1997 ---> 17 Oct 1997
Processing of DAFNE rare events at 183 GeV.
Known problems are:
- VFT hot pixel maps missing for part of data. (Note VFT is not used in the tracks)
- Non-linearity correction for HPC energy missing in ELEPHANT at XSDST level.
97_Z (NFT) proc 16 Oct 1997 ---> 19 Oct 1997
Processing of DAFNE rare events at 183 GeV with new forward tracking including VFT in tracks.
Known problems are:
- Non-linearity correction for HPC energy missing in ELEPHANT at XSDST level (Pixel problem is corrected)
97Z_D (NBT) proc 17 Oct 1997 ---> 22 Oct 1997 (97 Z0 data)
Known problems are:
- Non-linearity correction for HPC energy missing in ELEPHANT at XSDST level.
97H-D (NBT) proc 20 Oct 1997 ---> 10 Nov 1997
First complete processing of the 183 GeV data, ELEPHANT corrected.

At the end of 1997, the first full reprocessing using the NFT version of the tracking code was made, using the VFT points in the tracks. In addition, there were the following updates with respect to the D processing:

full VFT internal alignment.
modification of the fitting to use always single point TER from VFT, plus modification of the VFT DST structure.
module by module calibration of the HPC energy using he Krypton results.
FCA internal calibration for 97.
modification of the ID fix to correct one bad sector.
determination of scaling factors for detector error matrices.

Processings made were:

97Z-E (NFT) proc 20 Nov 1997 ---> 21 Nov 1997 (97 Z0 data)
97Y_E (NFT) proc 24 Nov 1997 ---> 26 Nov 1997 (DAFNE rare events from 97D)

Both the above processings suffer from a shift of 1 strip in the alignment of the VFT mini-strip planes in Rphi.

97H-E (NFT) proc 28 Nov 1997 ---> 9 Dec 1997 (183 GeV data)
97Z_E (NFT) proc 8 Jan 1998 ---> 10 Jan 1998 (rerun of 97E Z0 to correct VFT alignment problem)
97P_E (NFT) proc 10 Feb 1998 ---> 11 Feb 1998 (130 GeV data)

The VFT alignment is fixed by a shift of the TER inside Delana. A small offset in the HPC z coordinate, affecting part of the 183 GeV data in the E processing will be fixed in the E2 processing of DSTANA.

Comments/questions to John.Wickens@cern.ch

Last update Jan 19 1998