# Presentation: 185921

## AGS CNI polarimeter. Current Status.

*A RIKEN BNL Research Center Workshop** *
*A RIKEN BNL Research Center Workshop*

***AGS CNI polarimeter. Current Status.***

- BNL-2002

- Elastic scattering of polarized beam protons on a extremely thin carbon target with a small (~0.01 (GeV/c)2) momentum transfer. Large cross-section and a few percent analyzing power.

*Igor Alekseev (ITEP)*

## AGS setup

*A RIKEN BNL Research Center Workshop** *
*A RIKEN BNL Research Center Workshop*

***AGS setup***

- BNL-2002

*RSC  Meeting*

*Igor Alekseev (ITEP)*

- p

- 24mm

- 10mm

- Silicon strip detectors

- A carbon ribbon target:
- 300-600 m x 5 g/cm2

**Si STRIP**

**PREAMP**

**12 ns SHAPER**

**WFD**

**PC**

- In AGS tunnel

- In the HITL2 house

**Transformer**

- 25cm

## WFD Block Diagram

*A RIKEN BNL Research Center Workshop** *
*A RIKEN BNL Research Center Workshop*

**Virtex FPGA**

**Virtex FPGA**

***WFD Block Diagram***

*RSC  Meeting*

- CH1

- CH2

- CH3

- CH4

**Control CPLD**

**BUFF**

- CAMAC Databus

- 140 MHz

- 420 MS/s/ch **=** 2.4 ns/S

**DRAM**
**16 MB**

**DRAM**
**CNTR**

**Virtex FPGA**

- BNL-2002

*Igor Alekseev (ITEP)*

## FPGA Block Diagram

*A RIKEN BNL Research Center Workshop** *
*A RIKEN BNL Research Center Workshop*

***FPGA Block Diagram***

- BNL-2002

- ADC

**Virtex FPGA**

- 140 MHz

- Bunch 0

- Level Trigger

- Mean
- Subtraction

- Mean
- Calculation

- Bunch **#**** **and Pattern

- Amplitude

- Waveform
- FIFO / Delay

- CAMAC readout

- Time (CFD)

**1/4**

- Result
- FIFO

- Int/Ampl
- LUT

- Scalers and
- histograms:

- MUX

- Integral

- Time/Ampl
- LUT

**AND**

**x**2

- 70 MHz

**+1**

- SYNC and
- Window Logic

- Bunch **#** Distr

- Energy P**+** Distr

- Energy P**–** Distr

- Energy P0 Distr

- Special Scalers:
- P**+**,P**–**,P0, BG
- always accessible

- Control Logic

- INH

*RSC  Meeting*

*Igor Alekseev (ITEP)*

- GCC

## WFD features (V8)

*A RIKEN BNL Research Center Workshop** *
*A RIKEN BNL Research Center Workshop*

***WFD features (V8)***

- BNL-2002

*RSC  Meeting*

*Igor Alekseev (ITEP)*

-  8-bit amplitude and integral
-  1.2 ns time resolution
-  Bunch **#** information
-  Windowed sensitivity with 2.4 ns precision
-  Digital filter
-  Time/amplitude and integral/amplitude LUTs
-  LUTs programmable trough CAMAC
-  Bunch pattern memory
-  5 always accessible scalers (P**+**,P**–**,P0, 2*BG)
-  120 ch bunch distribution
-  3*128 ch amplitude distributions for P**+**,P**–**,P0
-  32*32 or 16*64 amplitude versus time histogram
-  Crate or front panel INHIBIT stops event recognition
-  16 MB of onboard SDRAM ~ 2.5·106 events
-  Special input for Gauss Clock Counts
-  Zero deadtime
-  Flexible  FPGA configuration

## Expected performance

*A RIKEN BNL Research Center Workshop** *
*A RIKEN BNL Research Center Workshop*

***Expected performance***

- BNL-2002

*RSC  Meeting*

*Igor Alekseev (ITEP)*

-  Ramp measurement: 2.4 – 24.5 GeV/c  a challenge for timing.
-  Event rate compare to RHIC:
-  CAMAC readout ~ 106 events / 3s ~ one spill.
-  5·108 events per ramp measurement ~ 500 spills · 106 events ~ 40 min.
-  Radiation damage to silicon. The whole RHIC statistics ~ 20 ramp measurements: one day !
-  Event rate per strip ~ 0.1 event per bunch crossing.

|  | RHIC 
(60-bunch mode) | AGS 
(6-bunch mode) | Factor |
| --- | --- | --- | --- |
| Target width | 10 m  | 500 m | 50 |
| Bunch frequency | 4.7 MHz | 2.3 MHz | 0.5 |
| -acceptance | 32o | 4.6o | 0.14 |
| Beam energy | 100 GeV | 25 GeV | 0.5 |
| Bunch filling | 1011 | 1.5·1011 | 1.5 |
| Total | 6 ·105 events/s | 1.6·106 events/s | 2.6 |

## Current status

*A RIKEN BNL Research Center Workshop** *
*A RIKEN BNL Research Center Workshop*

***Current status***

- BNL-2002

*RSC  Meeting*

*Igor Alekseev (ITEP)*

**DONE: **
- Silicon detectors, preamplifiers and BIAS power supplies are installed in the ring and tested.
-  Insulation transformers and shaping preamplifiers are installed in HITL2 and tested.
-  A new 2.5 GHz PC, CAMAC and 6 WFD modules installed in HITL2 and tested.
-  LeCroy 2367 universal module programmed to produce all necessary spill timing signals and prescale GCC.
**TO BE DONE:**
-  Get proper signals from AGS.
-  Get, install and test frequency multiplier.
-  Write DAQ and analysis software.