Loren Data's SAM Daily™

FBO DAILY ISSUE OF AUGUST 17, 2005 FBO #1360
SOURCES SOUGHT

59 -- The ALTRO (ALICE TPC Read Out) chip

Notice Date

8/15/2005
 

Notice Type

Sources Sought
 

NAICS

335999 — All Other Miscellaneous Electrical Equipment and Component Manufacturing
 

Contracting Office

Department of Energy, Brookhaven National Laboratory (DOE Contractor), Brookhaven, PO Box 5000 Bldg. No. 355, Upton, NY, 11973
 

ZIP Code

11973
 

Solicitation Number

Reference-Number-ALTRO
 

Response Due

8/25/2005
 

Archive Date

9/9/2005
 

Description

Brookhaven Science Associates, operator of the Brookhaven National Laboratory under USDOE Contract DE-AC02-98CH10886 is seeking additional sources for the ALTRO (ALICE TPC Read Out) chip. The only known source is through CERN, in Switzerland. The ALTRO (ALICE TPC Read Out) chip is a mixed analogue-digital custom integrated circuit dedicated to the digitization and processing of gaseous detector signals. It contains 16 channels operating concurrently on the analogue signals coming from 16 independent inputs. Upon arrival of a first level trigger, each input signal is sampled, processed and stored in a data memory. The maximum number of samples that can be continuously processed for each trigger (data stream) is 1008. When a second level trigger (accept) is received the data stream is either frozen in the data memory, till its complete readout takes place, or discarded. The data memory has the capacity to store 8 data streams. The analogue to digital conversion, the signal processing is performed in 5 steps: a first correction and subtraction of the signal baseline, the cancellation of long-term components of the signal tail, a second baseline correction, the suppression of the samples so close to the baseline that contain no useful information (zero suppression), and formatting. The data processing and the readout of the data memory are performed at different frequencies. Every single ALTRO channel is comprised of 7 main building blocks described hereafter: The analogue input signal is converted into a digital stream by an Analogue-to-Digital Converter (ADC) with 10-bit dynamic range and up to 40 MS/s sampling rate. The first baseline correction corrects the systematic instability of the signal baseline, allowing the subtraction of time-dependant pedestal values taken from the pedestal memory. At this step, the variations of the pedestal in between triggers are also self-corrected. Alternatively the pedestal memory can act as a look-up table, addressed by the input data, that can be used to perform a conversion of the input signal during the pedestal subtraction. Finally the pedestal memory can also be used to generate a test pattern; an important feature that allows a complete test of the overall processing chain without input signal. The signal of a gas detector is often characterized by a long tail with a rather complex shape. An accurate cancellation of the signal tail is required in order to perform efficiently the zero suppression. The tail cancellation filter is based on the approximation of the tail by the sum of exponential functions. Flexibility for the different 16 channels is also given by the possibility to re-configure channel by channel the digital signal processing by changing programmable coefficients. After the tail cancellation a second baseline correction corrects the perturbation of the baseline produced by non-systematic effects. Assuming that systematic and tail-dependant perturbations have been removed in the previous two stages, any remaining deviation is due to non-systematic effects. The second baseline correction computes a moving average on certain samples and then subtracts this value from the signal. The zero suppression is based on a fixed threshold pulse detection scheme, where samples of value smaller than a constant decision level (threshold), are rejected. To reduce the noise sensitivity, a glitch filter checks for a consecutive programmable number of samples above the threshold. In order to keep enough information for further feature extraction, a programmable sequence of pre-samples and post-samples is also recorded. Eventually, the merging of two subsequent sets, closer than 3 samples, is foreseen. The zero suppressed data is formatted in 40 bit words. Every block of samples is labeled with its time and length to allow posterior reconstruction. At the end of the acquisition period, the data block is labeled with a trailer word. The whole structure, is back-linked, that is, each trailer word points to the end of the previous data block. Trigger related data is stored in a multiple-event buffer. The Multiple-Event Buffer is a 1024x40 RAM partitioned in a programmable number (4 or 8) of fixed-length buffers. The data is continuously processed, when a trigger is received, a window (Processing Time Window, PTW) defines the stream of data to be formatted and stored in the multi-event memory. The implementation of the processing chain requires 18 pipeline stages. With this pipeline a programmable number of samples before the trigger (pre-trigger samples) can be stored by enlarging the PTW. This feature allows the compensation of the trigger latency to the extent of 15 times the sample clock period. The ALTRO chip interfaces to the external world through 16 analogue inputs, a 40 bit bidirectional bus and 8 control signals. The bus protocol is asynchronous for instructions, with a 2-line handshake. The readout, however, is a synchronous block transfer that allows a rate of up to 300 MBytes/s. Additional information may be found in the attached Specification. Interested suppliers should Contact David J. Paveglio
 

Place of Performance

Address: Brookhaven National Laboratory, Upton, New York

Zip Code: 11973

Country: USA
 

Record

SN00870351-W 20050817/050815211650 (fbodaily.com)
 

Source

FedBizOpps.gov Link to This Notice
(may not be valid after Archive Date)

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