A CNI Polarimeter for RHIC Spin Results from IUCF CE75 - PowerPoint PPT Presentation

About This Presentation
Title:

A CNI Polarimeter for RHIC Spin Results from IUCF CE75

Description:

A CNI Polarimeter for RHIC Spin Results from IUCF CE75 & AGS E950 M. Bai, G. Bunce*, H. Huang, Y. Makdisi, T. Roser, A. Rusek, M. Syphers Brookhaven National Laboratory – PowerPoint PPT presentation

Number of Views:129
Avg rating:3.0/5.0
Slides: 26
Provided by: Dougl344
Learn more at: http://physics.unm.edu
Category:

less

Transcript and Presenter's Notes

Title: A CNI Polarimeter for RHIC Spin Results from IUCF CE75


1
A CNI Polarimeter for RHIC Spin Results from IUCF
CE75 AGS E950
  • M. Bai, G. Bunce, H. Huang, Y. Makdisi, T.
    Roser, A. Rusek, M. Syphers
  • Brookhaven National Laboratory
  • K. Imai , M. Nakamura, J. Tojo, K. Yamamoto, L.
    Zhu
  • Kyoto University/ RIKEN
  • B. Bassalleck, S. Eilerts, D.E. Fields , B.
    Lewis, B. Smith, T.L. Thomas
  • University of New Mexico
  • Y. Goto, M. Ishihara, K. Kurita, N. Saito, A.
    Taketani
  • RIKEN
  • D. Underwood
  • Argonne National Laboratory
  • J. Doskow, K. Kwiatkowski, B. Lozowski, H.O.
    Meyer, B. v. Przewoski, T. Rinckel
  • Indiana University Cyclotron Facility
  • I. Alekseev, D. Svirida, V.Kanavets
  • ITEP
  • A. Deshpande, V. Hughes
  • Yale University
  • RIKEN/BNL Research Center

2
A CNI Polarimeter for RHIC Spin Results from IUCF
CE75 AGS E950
  • Motivation for CNI Polarimeter
  • CNI Theoretical Status
  • Initial tests - IUCF CE75 and Kyoto tests
  • AGS E950 Experimental Setup
  • E950 Analysis
  • E950 Results
  • RHIC Polarimeter Preliminary Design

3
Motivation
  • RHIC schedule
  • First Year running Oct.99 - Aug. 00
  • Siberian Snakes installed
  • Spin Rotators not installed yet
  • Commissioning only, No Spin Physics
  • Second Year running Oct. 00 - Aug. 01
  • Spin rotators installed
  • Higher (Blue Book) Luminosity
  • Good Physics (DG)
  • BUT Need relative polarimeter for First Year
    commissioning !

4
Motivationp C CNI polarimeter
  • Pros
  • Inexpensive setup
  • Solid target
  • High figure of merit
  • Little energy dependence
  • Polarization profile
  • Cons
  • Difficult Carbon recoil detection
  • Not absolute

5
TheorypC Coulomb Nuclear Interference
  • CNI is an interference effect between the purely
    Coulombic spin-flip term and the hadronic non
    spin-flip term in the scattering potential.
  • For the interference term to be important, the
    scattering must take place outside of the
    nucleus (rgtgtR), but well within the screening
    radius of the atomic electrons (rltltao).

6
Theory
  • CNI analyzing power is given by
  • so no direct energy dependence.
  • At 25 - 250 GeV, Hadronic AN is thought to be
    lt10 of
  • the CNI AN .

7
Theory
p
k
qp-k
pp
12C
pC
t -q2
E950
900keV
450keV
8
Measurementspp elastic at 200GeV/c
(E704)Physical Review D48 (1993) 3026-3036.
Curve has no hadronic spin flip.
9
Initial tests - IUCF CE75
10
CE75 Silicon
  • Two standard Silicon detectors around 90o.
  • Off-the-shelf on-board pre-amps.
  • Cooled FETs and silicons.

11
IUCF CE75 Results
  • Red points are for detector closer to 90o.
  • So, green points (more forward detector) have
    higher Carbon energy.
  • Matches predicted angle vs. energy.
  • 200KeV threshold.

12
Silicon Detector Re-design
  • 12 Channel 6 channel.
  • On-board pre-amps.
  • Cooled by mount.

Silicon Detector
Pre-amp location
13
Initial tests - Kyoto
14
Kyoto Results
  • Could resolve down to 200keV Carbon recoils.

15
AGS E950 Experimental Setup
16
AGS E950 Experimental Setup
TOF measurement
Micro ribbon Carbon target
MCP
MCP
e
e
C
Silicon strip detector
Carbon foil
0
13
25 cm
Energy measurement
17
Targets
  • Carbon Ribbons
  • 6mm wide
  • 3.7mg/cm2 thick
  • 3cm long

18
Micro-Channel-Plate Detectors
Si PC board
Silicon
MCP
Repeller
e-
12C
Mirror
MCP
Accelerator
C foil
Mirror
19
Data Acquisition
  • Read out events at end of spill.
  • Home made Linux based acquisition.
  • On-line analysis capable.

20
E950 On-line Analysis
  • Target out configuration still had a frame.
  • Rate was sensitive to beam position.

Target Out
Target In
Carbon
TDC distribution
ADC distribution
21
E950 Analysis
  • Bunch width was 25ns.
  • TDC start was beam RF.
  • Inherent 7.2ns width from beam bunches.
  • Using Si - MCP gives inherent Si time resolution
    of 2.5ns .

Si only
Si -MCP
s2.5ns
s7.5ns
Projection along the profile
22
E950 Analysis
  • Since E calibration not good (yet), use time
    slices to get -t bins.

Carbon band
4 sigma cut
TDC Values (ns)
6 time bins
prompt
ADC values(ch)
23
E950 Results
-t
  • Follows general trend expected.
  • Not yet absolute (at any scale).

E950 Preliminary
Asymmetry
Error bars are statistical only
Time bins
24
RHIC Polarimeter Preliminary Design
25
RHIC Polarimeter Preliminary Design
Write a Comment
User Comments (0)
About PowerShow.com