Liverpool BeO Forward Hybrid with ABCD

DAQ
PCI Pentium 200MHz running LINUX.
BIT3 Model 617 PCI-VME adaptor.
RAL DRAFT.
RAL SEQSI Sequencer(s).
Melbourne Barrel Support Card with Forward Hybrid Kapton adapter cable.
Floating Power Supplies for VCC and VDD.

2 hybrids have been evaluated at Liverpool

Hybrid 1
6 x ABCD-N on single side of hybrid.
2 x Hamamatsu N on N detectors bonded together to make 12cm.
The detector is only bonded to the first 3 chips.

Hybrid 2
6 x ABCD-N on single side of hybrid.
The first 5 ABCDs have been mounted onto individual Aluminium foil substrates using conductive glue. A wire bond connection can then be made/broken from the foil substrate to AGND. The backplanes on these 5 chips has been removed so that an electrical
connection can be made between the foil substrate and chip backplane.
Chip 6 has no foil substrate, it has been mounted in the normal way using non-conductive epoxy.
The primary function of this hybrid is to check ABCD performance with/without the backplanes of the chips connected to AGND.
The last ABCD (chip 6) was used as a reference chip, as this has not been modified in anyway w.r.t. the backplane etc.

Results (EDGE mode enabled at both the Front and Back-end of the ABCDs)
The following results for both hybrids have been obtained with the front-end bias set for the high (211.6uA) and low (73.6uA) current regions. Threshold was scanned from 0mV - 625mV in 2.5mV steps, injected charge was from 1fC to 4fC in steps of 0.5fC. The results shown are for injected charges of 2fC, 3fC and 4fC (in either JPEG or Postscript format).

Hybrid 1 high current operating region

Input noise (fC) with/out 12cm detector, noise1.jpeg or noise1.ps
Gain (mV/fC), with/out 12cm detector, gain1.jpeg or gain1.ps
Threshold uniformity (mV), with/out 12cm detector, threhold1.jpeg or threshold1.ps

Hybrid 1 low current operating region
NOT YET AVAILABLE!!!!!!!!!!!!!!

Hybrid 2 (bare hybrid) operating in the high and low current regions

Input noise (fC), with foil substrate connected to AGND, noise2agnd.jpeg or noise2agnd.ps
Input noise (fC), with foil substrate open circuit, noiseo/c.jpeg or noise2/oc.ps
Gain (mV/fC), with foil substrate connected to AGND, gain2agnd.jpeg or gain2agnd.ps
Gain (mV/fC), with foil substrate open circuit, gain2o/c.jpeg or gain2o/c.ps
Threshold uniformity (mV), with foil substrate connected to AGND, thres2agnd.jpeg or thres2agnd.ps
Threshold uniformity (mV), with foil substrate open circuit, thres2o/c.jpeg or thres2o/c.ps

The results for Hybrid 2 show that performance is better when operating in the low current region, when compared to those results obtained for the high current region:

Threshold is more uniform across the chip and channel offset has been reduced considerably.
There is reduced gain spread.
Improved noise performance, the ENC is now aprroximately 600e (for bare chip performance).

But there is no overall improvement in hybrid performance when the chip backplanes are connected to AGND.

Other items of interest related to the Liverpool Forward Hybrid:

The ABCD Efficiency Problem

NEW!!! (20/10/98) First results for the Forward Hybrid with 12 x ABCD readout.

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