EDOC302

 


EUROBALL DATA ACQUISITION SYSTEM

Group and Item Number Allocation


Edition 1.3 - Sept 23 1996
Edition 1.4 - Oct 12 1998
Edition 2.0 - Dec 7 1998
Edition 2.1 - Mar 24 1999

 

Nuclear Physics Support Group
Central Laboratory of the Research Councils
Daresbury Laboratory


Group and Item Number Allocation for Euroball

This document defines the allocation of group and item numbers used by the Euroball VXI electronics. For a description of the raw data format which uses these numbers see the document edoc300.

Group number allocation for Euroball

The allocation of groups for Euroball is an extension of that used for Eurogam.

detector type group numbers
ReadOut Controllers (STR 8080) 248 - 255
Master Trigger 247
BGO Inner Ball (Eurogam IV) (raw data) 81 - 99
BGO Inner Ball (Eurogam IV) (sum) 100
Tapered (Eurogam I) 51 - 80
Clover (Eurogam II) 21 - 50
Cluster (Euroball III) 1 - 20

Note - Eurogam uses group 255 (only) for all readout controllers and for the master trigger module.
The group number space between 101 and 240 is available for use by readout systems for ancillary detectors within Euroball.

Item number allocation for the Eurogam Master Trigger VXI card.
Used for initial Euroball experiments

The Eurogam Master Trigger card generates the following data items.

data item item number
event type 0
Raw Ge Sumbus 1
Clean Ge Sumbus 2
BGO Sumbus 3
User Sumbus 4
Timing (TAC) 5

Item number allocation for the Euroball Master Trigger VXI card.
known as Trigger MK2

The Euroball Master Trigger card generates the following data items.

data item item number
Sumbus 1 Multiplicity 0
Sumbus 2 Multiplicity 1
Sumbus 3 Multiplicity 2
Sumbus 4 Multiplicity 3
TAC 4
Pattern/trigger type 5
Event Number LSB 6
Event Number MSB 7

Item number allocation for the Euroball Ge/BGO VXI cards.

The Ge card provides 6 electronics channels each of which instrument one Euroball Ge tapered detector. Each channel has 4 ADCs.

ADC item number
20Mev 0
4Mev 1
Timing (FT) 2
Timing (CO) 3

The BGO card provides 6 electronics channels each of which instrument one BGO shield for a Euroball Ge tapered detector. Each channel has 3 ADCs.

ADC item number
total energy (Energy) 4
timing (TAC) 5
hit pattern (Pattern) 6

Item number allocation for the Euroball Clover VXI card.

The Clover card instruments the 4 element Euroball Ge Clover detector and its associated BGO shield. For the purposes of this note the Ge elements will be labelled as Ge-element# which takes the values 1 => 4. Each element has 4 ADCs which will be labelled as adc# which takes the values 0 => 3.

ADC adc#
20Mev 0
4Mev 1
Timing (FT) 2
Timing (CO) 3

The item number is given by

(Ge-element# - 1) * 4 + adc# + 8

which has the values 8 => 20.

The Euroball data acquisition control system identifies the elements as GeA to GeD where A is element number 1 and D is element number 4. Thus

        GeA.20Mev               is item                 8
        GeA.4Mev                is item                 9       through to
        GeD.CO                  which is item           23

The Ge electronics includes one spare element which can be switched in to replace any one of the normal 4 elements in the event of a failure. This spare element will be assigned the item numbers allocated to the element it has replaced.

The Clover BGO electronics instruments the Clover detector BGO shield and provides 3 sum data items.

data item item number
total energy (Energy) 4
timing (TAC) 5
hit pattern (Pattern) 6

Item number allocation for the Euroball Cluster VXI card.

The Cluster Ge card instruments the 7 element Euroball Ge Cluster detector. For the purposes of this note the elements will be labelled as Ge-element# which takes the values 1 => 7. Each element has 3 ADCs which will be labelled as adc# which takes the values 0 => 2.

ADC adc#
20Mev 0
4Mev 1
Timing (FT) 2

The item number is given by

(Ge-element# - 1) * 3 + adc#
which has the values 0 => 20.

The Euroball data acquisition control system identifies the elements as GeA to GeG where A is element number 1 and G is element number 7. Thus

        GeA.20Mev               is item                 0
        GeA.4Mev                is item                 1       through to
        GeG.FT                  which is item           20

The Cluster BGO card instruments the 18 element Euroball BGO shield and back-catcher. For the purposes of this note the elements will be labelled as BGO-element# which takes the values 1 => 18. Each element has 2 ADCs which will be labelled as adc# which takes the values 0 => 1. Additionally the BGO electronics provides 3 sum data items.

data item item number
sum BGOSum.Energy 21
sum BGOSum.TAC 22
hit pattern BGOPattern.High 23
hit pattern BGOPattern.Low 24

and

ADC adc#
Energy 0
Timing 1

The item number is given by

(BGO-element# - 1) * 2 + adc# + 25
which has the values 25 => 60.

The Euroball data acquisition control system identifies the elements as BGOA to BGOR where A is element number 1 and R is element number 18. Thus

        BGOA.Energy             is item                 25
        BGOA.TAC                is item                 26      through to
        BGOR.TAC                which is item           60

Both the Ge and BGO electronics include one spare element which can be switched in to replace any one of the normal 7 or 18 elements in the event of a failure. This spare element will be assigned the item numbers allocated to the element it has replaced.

Item number allocation for the Euroball IV BGO Inner Ball VXI cards.

The BGO VXI card provides 6 electronics channels each of which can instrument 10 BGO Inner Ball segments. Each channel has 3 ADCs.

ADC item number
total energy (Energy) 0
hit pattern (Pattern) 1
timing (TAC) 2

The total energy data item will be the sum energy of the group of 10 bgo segments connected to that input and the hit pattern will have a bit set for each segment which has fired and thus can give the multiplicity for the group of segments.

A Sum group will be generated in software by summing all the partial energies and calculating a total BGO multiplicity.

item item number
total energy (Energy) 0
multiplicity (Mult) 1

Item number allocation for the GIR.

item item #
error report 63
event number (EvNum) 62 (61 - see note)

All VXI cards which use the GIR for VXI interfacing have a number of common data item generated within the GIR.
The error report item is used by the GIR to report various internally detected errors. The error cause is reported as a code in the data part of the 32 bit data word.
The event number item is the reconstructed event number generated by the GIR using the algorithm defined in the document EDOC301.

Note - In the case of the Cluster electronics which is in fact 2 VXI cards the Ge card GIR is allocated item number 62 and the BGO card GIR is allocated item number 61.

Group and Item allocation for the ReadOut Controllers (VRE).

The ReadOut Controllers use groups 248 - 255. Each group corresponds to a physical DT32 readout bus and can accomodate 15 ReadOut Controllers. For VRE module n (i.e. VREn) the group number used is given by 248 + (n/16). Hence the first DT32 bus (with n=0) has VRE modules VRE1 => VRE15; and the second DT32 bus (with n=1) has VRE modules VRE17 => VRE31 etc.

For a specific DT32 bus each VRE has a number i given by n modulo 16 or n - ( (n/16) * 16). The first VRE on the DT32 bus has i=1 and the last has i=15. If there is only one VRE on the DT32 bus then it has i=15. For further details see the document EDOC300.

The use of item numbers by the ReadOut Controllers is thus

data item item number item number range
start sub event token i 1 - 15
event number LSW i + 16 17 - 31
event number MSW i + 32 33 - 47
end sub event token i + 48 49 - 63

No VRE uses the value i=0 and hence the items 0,16,32 & 48 are not allocated.