Electronics for detectors

As outlined in section 6, the basic scheme of the data acquisition is along the current Hall C standard DAQ system.

Table 23 summarizes the number of required read-out channels for each detector. Signals from the drift chambers (HDC1, HDC2, EDC) are amplified and discriminated by Nanometric 277L amplifier-discriminator boards (16 ch/board). These boards are mounted on the chambers and timing information of the output ECL signals is recorded by FastBus TDC (LeCroy 1877). The FB TDC is now commercially unavailable and there is an option to replace the TDC by F1-Chip TDCs newly developed at Jlab, if the development is finished in time.

The PMT signals will be recorded with ADC (LeCroy 1881) and high resolution TDC (LeCroy 1872A). Since we require very good timing resolution ( $\sigma \sim 50$ ps) for the TOF counters (HTF1X, HTF1Y, HTF2X, HWC1, HWC2, EHOD1, EHOD2, EHOD3), the discrimination of these signals to the logic signals will be carried out in the Hall C to have better timing resolution. The TDC for the EHOD counter could be again replaced by the F1-TDC if F1-TDC high-resolution mode works fine.

The HKS detectors are grouped into six to make the HADRON PID triggers. This grouping is to reduce the overkill rate by veto. The combination of groups will be primarily determined with a simulation and it will be optimized with real data during the commission run. In order to re-arrange the combination of the groups easily, a new logic module with a FPGA (Altera APEX-20K300E) which enables the logic to be re-programmed without any change of cabling, is now under development.

表 23: Detector and read-out electronics summary

Name	Detector	Read-out Method	Channels	HR TDC	TDC	ADC
HKS detectors
HDC1	Drift Chamber	Nanometric N277L	660		660
HDC2	Drift Chamber	Nanometric N277L	720		720
HTF1X	TOF hodoscope (X)	PMT H1949	34	34		34
HTF1Y	TOF hodoscope (Y)	PMT H1949	18	18		18
HAC1	Aerogel Cerenkov	PMT R1250	14	14		14
HAC2	Aerogel Cerenkov	PMT XP4572B/D1	14	14		14
HAC3	Aerogel Cerenkov	PMT XP4572B/D1	14	14		14
HTF2X	TOF hodoscope (X)	PMT H1949	36	36		36
HWC1	Water Cerenkov	PMT H7195	24	24		24
HWC2	Water Cerenkov	PMT H7195	24	24		24
Sub total				178	1380	178
Enge detectors
EDC	Honeycomb DC	Nanometric N277L	1120		1120
EHOD1	TOF hodoscope (X)	PMT H6612	50	50		50
EHOD2	TOF hodoscope (Y)	PMT H6612	50	50		50
EHOD3	TOF hodoscope (Y)	PMT H1949	2	2		2
Sub total				102	1120	102
Fast raster						4
BPM						16
Grand Total				280	2500	300