Ring Separated and Event Selected Data Files
Many INDRA analysis tasks require only data of a single ring or of two
adjacent rings which share a Chio. Data files which contain only
information of such a ring subset will store more events per unit of
storage volume and thus allow in many cases a faster analysis.
We so far have created 11+1 extractions:
r01 Ring select: R 1
r02_r03 Ring select: R 2/ 3
r04_r05 Ring select: R 4/ 5
r06_r07 Ring select: R 6/ 7
r08_r09 Ring select: R 8/ 9
r10_r11 Ring select: R 10/11
r12 Ring select: R 12
r13 Ring select: R 13
r14_r15 Ring select: R 14/15
r16_r17 Ring select: R 16/17
etalon Module select: Etalons
etaevt Event select: Etalons
The basic logic of the production program is very simple and based on two
`masks' per extraction, the `RequiredMask' and the `CopyMask'. A mask is
nothing but a list of labels, entered into the program via a list of
parameter names.
The program does for each event and extraction
- a check whether there is any parameter in the RequiredMask
- if this was successfull copies all parameters in the CopyMask
into the associated output stream
Ring/Module selections
Most of the files are ring or module selections. In this case
subsets of the events are generated, holding the hits of
a particular ring or module selection. In these cases:
- The RequiredMasks include only the analog signals of the
particular set of modules, they do not include the time markers.
- The CopyMask includes
CONFIG,R_DEC,STAT_EVE
ECH_01_UP,...,ECH_08
PATTERN
MULT_SI,MULT_CSI,MULT_HIT
all the analog and time signals of the particular modules
all PILA and SI_PIN signals
Note that:
- only the first 8 scalers are copied
- the MT4_G2_09 .. MT4_G3_16 are not copied
- three new parameters are always copied, MULT_SI,
MULT_CSI, MULT_HIT
Some other features worth mentioning are:
- The JBUS buffers are passed. This allows to use them as
a time marker.
- The SCALER buffers are currently not passed.
- Two new parameters are defined and properly declared in the
PARAM buffers:
MULT_SI
MULT_CSI
MULT_HIT
MULT_SI and MULT_CSI contain the Si and CsI
multiplicity of the original event, repectively. The multiplicity
is determined by counting the
number of complete (PG,GG,T) or (R,L,T) triplets, so single time
markers or ADC's without a time marker are not counted.
MULT_HIT is calculated as the number of modules with some
analog information for a Si, Si75, SiLi or CsI. Note, that the
Chio's and the time marker are not included in this
algorithm. MULT_HIT should be a good estimate for the
number of particles, while MULT_SI and MULT_CSI
can be used to distinguish pulser, laser and
physics events in runs where PATTERN is unavailable.
- The PARAM buffers contain by popular demand the
description of all
parameters, and not just those available in the particular extract.
- All bad events with a (-1,-1) label/value pair are discarted.
- The overflows are handled slightly differently compared to
the original raw data ! In the original files an ADC overflow
produces a value of 4095 AND a label with the sign bit
set (so you'll see in effect a negative label).
In the `ring separated' files the sign bit of the label
is not set in case of an overflow, the only signature
of an overflow is a value of 4095.
Event selections
The etaevt selection is in contrast to the other cases
an event selection. In this case the complete raw data event
is copied if a condition is fullfilled. As a consequence, the CopyMask
is simply a list of all available parameters. There are currently
the following selections:
- etaevt: Events with an Etalon module
- The aim is to study the etalons under global event cuts beyond
what is possible with the stored multiplicities like MULT_SI
on the etalon extraction. A prestudy showed the following
relative size of the output file for a typ. run (4625):
Selection |
Size |
every event where a Si75, SiLi or CsI ADC fired |
48.2% |
as above, but pulser and laser events excluded |
26.3% |
every event where a Si75 or SiLi time marker fired |
13.1% |
as above, but pulser and laser events excluded |
5.4% |
A selection based on the time markers selects only the events
where an etalon was really hit while a selection based on the
presence of the analog signal essentially selects all events
where the module was hit. Because of the much better selectivity
the time marker selection was used.
Configuration files
The configuration files (look for cmask*.conf and rmask*.conf)
are accessible under
http://www-kp3.gsi.de/dat/cvs/s185/conf/
See also the summary of the configuration settings
which gives in a quite readable tabular fashion a compressed representation
of the configuration files.
A list of available tapes with ring separated
data is given elsewhere.
See also the description of
IDH_rawmultiselect.
Back to INDRA Raw Data
Walter F.J. Mueller
Last modified: Thu Mar 2 16:58:48 CET 2000