# Presentation: 177382

## RHIC pC polarimeterwhat has been achieved and what needs to be done

- Osamu Jinnouchi
- RBRC
- 2/10/05 RSC meeting

## Outline

-  Brief description of system and data
-  Some measurement performances (Run-04)
-  Summary of the systematic errors
-  Calibration using Jet-target : obtained AN
-  Offline polarization results of Run-04
-  Consistency check with online result
-  Corrections with newly obtained AN for past runs
- The things can be done with Run-04 data

- Osamu Jinnouchi RBRC

- 2/10/2005

## Detector layout

**Strips are parallel to the beam direction**
**72 strips x 2rings **
**45degree detectors (1,3,4,6) see reduced A****N**** (by 1/sqrt(2))**

- Ultra thin Carbon ribbon Target
- (3.5g/cm2)

- 1

- 3

- 4

- 5

- 6

- 2

- Si strip detectors
- (TOF, EC)

- 15cm

- 10mm

- 2mm pitch 12 strips

- p+ implants
- ~150 nm depth

**72 strips in total**

- Thin dead layer for low  energy
- carbon spectroscopy

- Osamu Jinnouchi RBRC

- 2/10/2005

## DAQ and Data types

**Offline data **
**   ****typically**
**15M carbon selected events**
**      ****(27M overall events)**
**      ****corresponds to 170MB size**
**DAQ time : ~10 seconds**
**Readout time: 3min **

- Wave Form Digitizer (WFD)

- 20M events / 20sec
- - Pulse Height    - Bunch ID
- - TOF                 - Integral (Q)

- Select carbons at on-board LUT
-  Scaler data
-  Asymmetry calculation
-  Online results (to experiments)

- Event by event data
-  Stored in on-board memory
-  Used for offline detailed study

**~50ns**

**~100mV**

**Bunch**

**Next Bunch**
**(213ns)**

**Shaped Si Signal**

- offline

- online

- Osamu Jinnouchi RBRC

- 2/10/2005

## Strip by strip asymmetry study

**Each strip can be considered as individual polarimeter (******** vs. ******** asymmetry)**
**The deviation more than statistical error turned out to be negligible (2 parameters)**
**(Used data set is what is used for Jet calibration, i.e. Blue ring 100GeV)**
**Great achievement in Run-04**

- Number of carbons in i-th strip for
- Up(Down) spin

- Deviations from Fit (projection)

- Fit with sine function (2 parameters)

- Osamu Jinnouchi RBRC

- 2/10/2005

- Strip by strip (azimuth angle study)

- Rotator
- ON

- Rotator
- OFF

- Rotator
- ON

- Best fit of all
- blue points

**Fill by fill fluctuation**** is explained as a statistical behavior**
**To reach d********= 20mrad (the error size of red points), 32 CNI runs needed**
**Good sensitivity to spin angle measurement**

- BLUE 100GeV
- With Jet

- Osamu Jinnouchi RBRC

- 2/10/2005

## Strip by strip at 24 GeV (in blue)

**16 CNI runs of 24GeV data taken with Jet (including longer runs)**
** ****Angle: zero consistent with good statistics**
** ********2****/ndf : not so bad  **

- Osamu Jinnouchi RBRC

- 2/10/2005

## Beam profile issue ??

**We claimed that we observed significant polarization profile**
**Is it a fine statement ?**
**Within a FWHM we cannot tell the difference**
**If we control it by *****mm***** precision, it would be fine**

**Yellow**** **
**target scanned vertically**

**Yellow**** **
**In different fill**

- 1mm

**polarization**

**beam intensity**

- Osamu Jinnouchi RBRC

- 2/10/2005

## Beam profiles (in other ring)

- Blue is also the same situation
- Only one scan saw a very weird profiles in both intensity and polarization

- Blue horizontal scan

- Blue vertical scan

- Osamu Jinnouchi RBRC

- 2/10/2005

## Beam profile issue will be gone, anyway

**In the new application tool for the RHIC polarimeter (available from Run-05), the beam center finding (fast target scan) will be done automatically and easily**
**As long as the target is sitting away from the beam edges, we can avoid the profile issue**
**Also with the new RHIC application, the plan is to make regular measurements with the target moving back and forth**
**Seth Nemesure**** (CAD) is working on this application**
**We need commissioning of this new tool at the beginning of pp run **

- Osamu Jinnouchi RBRC

- 2/10/2005

## List of systematic errors 

| Items | Run02 |  | Run03 |  |  | Run04 |
| --- | --- | --- | --- | --- | --- | --- |
| Difference between e90 vs. e45 (run by run) | Statistically fluctuate with small deviation from zero
(reasons were not understood) |  | N/A but expected to be very small from the azimuth fit to the strip by strip asymmetries |  |  |  |
| Radial component (run by run) |  |  |  |  |  |  |
| Cross asymmetries (run by run) |  |  |  |  |  |  |
| Bunch by bunch azimuthal fit (removing bad bunch) | DONE |  | N/A |  |  |  |
| Bunch dependent systematic error (Bunch shuffling)  | Almost statistical behavior |  | N/A |  |  |  |
| Event cut dependence (mass 2vs.3 sigma cuts) | N/A | Run03 See the significance
0.005-0.015  in Polarization |  | Run04 see the absolute difference relative 3%
(dP=0.012 for P=0.40) |  |  |
| (1) dP/P from Jet | N/A |  | N/A |  | 0.085 |  |
| (2) Energy correction ambiguities | Estimated ±5ug/cm2 |  | Same |  | ±12ug/cm2 |  |
|  |  |  |  |  |  |  |

- Osamu Jinnouchi RBRC

- 2/10/2005

## Energy correction estimation

- Fits with non-relativistic kinematics
- With the factor 1181.6, the fit is forced to the Carbon mass (11.17GeV/c2)

- 3 Mass cut

**Time of Flight (ns)**

**Energy (keV)   **

- Osamu Jinnouchi RBRC

- 2/10/2005

## Determination of dead layer from fit

- Fit 400-1000keV

- Fit 200-550keV

- flattop

- injection

**200-550 ****keV**

**200-700 ****keV**

- Luminocity
- (or DAQ rate)

- correction

- Osamu Jinnouchi RBRC

- 2/10/2005

## What makes difference in dead layer btw injection/flattop

**At flattop the carbon locus is closer to the timing threshold**
**At high luminosity, the carbon locus is distorted from the actual shape**

- Real center

- Faked center

- (hand drawing)

- Fit range

- Looks OK

- Looks OK

- High luminosity
- 100GeV 80ug/cm2

- Low luminosity
- 100GeV 64ug/cm2

- High luminosity
- 24GeV 52ug/cm2

- Osamu Jinnouchi RBRC

- 2/10/2005

## Energy correction for Run-04 Silicons

- Silicons are extracted from the same wafer for each ring
- Fit within 300-1000keV: use the average value from injection measurements
- Blue 57ug/cm2 , Yellow 53ug/cm2
- The uncertainty is assigned as ±12ug/cm2
- From the fluctuation between strip by strip
- This is also consistent with the systematical difference between injection/flattop
- The correction may includes multiple effects from silicon, electronics, etc.

- si-1

- si-2

- si-3

- si-4

- si-5

- si-6

**Estimated Si dead layer width (Fit Range 300-1000keV)**

- si-1

- si-2

- si-3

- si-4

- si-5

- si-6

**BLUE**

**YELLOW**

- Due to horizontal target

- Osamu Jinnouchi RBRC

- 2/10/2005

## Carbon cut dependence

- Other systematic error is the cut dependences on the carbon mass

- BLUE 100GeV through the run

- BLUE 100GeV   1.030+/-0.0008  2/ndf = 277/124
- BLUE   24GeV   1.033+/-0.0007             = 136/31
- Yellow 100GeV  1.033+/-0.0014             = 110/98
- Yellow   24GeV  1.034+/-0.0010             = 67/24
**So we expect 3% relative change due to the cut **

-  

- Time in days (since 4/1)

- Errors are estimated with extended version of D.Kowell’s formula i.g.

**(when one data set is subset to the other)**

- Osamu Jinnouchi RBRC

- 2/10/2005

## AN(t) reported at Spin-04

*pC* AN(t) was reported in spin-04 Conference
- Two main systematic errors (P/P from jet 8.5%, Energy correction) were combined **linearly** (magenta band)
- Since two components are independent, they should be summed in **quadratic** (light blue band)

**Revised systematic band**

- Osamu Jinnouchi RBRC

- 2/10/2005

## Comparison of ANjet and ANE950

- Jet calibrated AN is smaller than the Larry’s fit to E950
- The ratio dramatically changes in momentum transfer *–t*
- Since we do not have a new AN at 24GeV, we will use these for the offline values
- 24GeV – use E950 AN(*t*)
- 100GeV – use new 100GeV AN(*t*)

- Ratio is for each point

- Osamu Jinnouchi RBRC

- 2/10/2005

## Offline results of run-04 (compared with online values)

- BLUE 100GeV
- 3 sigma mass cut
- Use new AN(t)

- 1.247+/-0.01

- 1.079+/-0.005

- Red points: offline

- Blue points: online

- Time in days (from 4/1)

- When online energy correction changed from 50ug/cm2 to 66ug/cm2 at May 1st

- Offline/online

- Average P
- after May 1st

- Only the CNI runs taken with event mode data are selected

- Osamu Jinnouchi RBRC

- 2/10/2005

## Run-04 blue 24GeV

- 0.94+/-0.004

- 3sigma mass cut
- Use E950 AN(t)

- Red points: offline

- Blue points: online

- Offline/online

- Average P
- after May 1st

- Osamu Jinnouchi RBRC

- 2/10/2005

## Run-04 Yellow 100GeV

- 1.112+/-0.006

- 1.211+/-0.02

- 3sigma mass cut
- Use new AN(t)

- Red points: offline

- Blue points: online

- Offline/online

- Average P
- after May 1st

- When online energy correction changed from 49ug/cm2 to 60ug/cm2 at May 1st

- Osamu Jinnouchi RBRC

- 2/10/2005

## Run-04 Yellow 24GeV

- 1.05+/-0.01

- 0.98+/-0.008

- 3sigma mass cut
- Use E950 AN(t)

- Red points: offline

- Blue points: online

- Offline/online

- Average P
- after May 1st

- Osamu Jinnouchi RBRC

- 2/10/2005

## Short history since RHIC retreat-04

**in offline analysis**
-     P(jet-offline, **selected runs**) = 0.386+/-0.033
-     P(pC-online,   **selected runs**) = 0.359+/- small err
-     factor = 0.386/0.359
-            = **+1.075**
-     P(jet-offline,  **all runs**) = 0.392+/-0.026
-     P(pC-online,    **all runs**) = 0.377 +/- small err
-     factor = 0.392/0.377
-            = **+1.040**
-   [comment]
-     from D.Kowell's formula, 1sigma of the two
-     data sets would be (one is subset of the other),
-             sqrt(0.033**2-0.026**2) = 0.020
-     then the second factor (for example) could have error
-             (0.392+/-0.02)/0.377 = **1.040+/-0.053**

- Consistency check between **all **and **selected** runs

**at online**
-     P(jet-online) = 0.369 +/- 0.02
-     P(pC -online) = 0.381 +/- small err
-     factor = 0.369/0.381
-            = **+0.969**

- Osamu Jinnouchi RBRC

- 2/10/2005

## In the past runs, how the AN was determined ??

**In Run02**
- Fixed AN values were used for all the runs
-  BLUE -t = 0.007-0.030  AN=0.0127+/-0.0040
-  YELL -t= 0.006- 0.027  AN=0.0133+/-0.0041
- These values were obtained from J.Tojo, where he used the asymmetry information of both E950 and RHIC CNI to estimate AN value at RHIC*-t* range (lower *-t*)
- Since the RHIC asymmetry saw the rather large asymmetry in the lower *–t* region, this analyzing power is estimated larger than simply estimated from E950

- Osamu Jinnouchi RBRC

- 2/10/2005

## In the past runs, how the AN was determined ?? –2 

**In Run03 Offline**
- Used effective AN based on the Larry’s function fit to E950 data points: weighting by the number of event is the idea
- -t range was chosen to
-      Blue     *–t* = 0.0134 – 0.0201   (600-900keV)
-      Yellow *–t* = 0.0112 – 0.0201   (500-900keV)
- This rather high –t values are due to large energy correction
**In Run04 online**
- The same as in run-03, but in wider –t range
-      Both rings *–t* = 0.00716 – 0.0224 (320-1000keV)

- Osamu Jinnouchi RBRC

- 2/10/2005

## How the correction factors are calculated

- For Run-02
- Recalculate the effective AN(t) within the defined *–t* range, and simply replace it
- For Run-03
- Need to take the ratio of effective AN(t) from E950 and Jet calibration
- For Run-04
- Compare the online and offline (new AN is taken into account) results
- All of these takes into account the N(t) (cross section shape) from the data
- The result does not change by using elastic shape N(t) = N0Exp(-Bt)

- Osamu Jinnouchi RBRC

- 2/10/2005

## Correction factors

**If we simply take the ratio of A****N****(t) integrations**

**If we define the jet calibrated pC A****N****(*****t*****)**
** ****with 66 ug/cm****2 ****energy correction (shift in *****–t***** )**

**Integration range is defined for each year and ring**

**Run04**

- Osamu Jinnouchi RBRC

- 2/10/2005

## Correction factors for the past runs

**Correction Factors**
**Run-02**** ****Blue****     **Pol goes up by** ****8.9%**** **(+13.6%-11.3% of itself)
**                 ****Yellow**** **Pol goes up by** ****3.8%**** **(+13.4%-11.0% of itself)
**Run-03**** ****Blue****     **Pol goes up by** ****23%****  **(+13.6%-12.7% of itself)** **
**                 ****Yellow**** **Pol goes up by** ****21%****  **(+13.0%-12.7% of itself)
**Run-04 ****Yellow**** **Pol goes up by** ****11.2%****  **(+12.3%-11.8% of itself)
**     ****Online****  ****Blue ****    **Pol goes up by**  ****7.9%****   **(only Pjet error = ±8.5%)
-       Note: only runs after 5/1 are considered

- Osamu Jinnouchi RBRC

- 2/10/2005

## Consistency (relations)

- Ratio

**BLUE**

- 1

- R=1.079 dl=66ug/cm2

- R=1.247 dl=50ug/cm2

**Offline R=1.17 dl=57ug/cm****2**

******R=0.08 ********dl=7ug/cm****2**

******R=0.10 ********dl=9ug/cm****2**

**By changing A****N****(E950********Jet)**

- Ratio

**YELLOW**

- 1

- R=1.112 dl=60ug/cm2

- R=1.211 dl=49ug/cm2

**Offline R=1.17 dl=53ug/cm****2**

******R=0.04 ********dl=4ug/cm****2**

******R=0.06 ********dl=7ug/cm****2**

**By changing A****N**

- E=1g/cm2 ~ P/P=0.01

- Osamu Jinnouchi RBRC

- 2/10/2005

## The things need to be done with Run-04 data

- 24GeV calibration
- Not satisfying statistical accuracy, but worth to see any deviation from E950 curve
- Spin turn by turn frequency measurement
- By using the unique bunch crossing id, pursue the turn by turn asymmetry (spin precession)
- Fourier frequency analysis is the way to go
- (maybe) I can play with this data during the next week

- Osamu Jinnouchi RBRC

- 2/10/2005

## Summary 

- RHIC pC polarimeters are becoming very stable device and precise tool to measure the polarization
- Good quality data samples enable to explore the interesting features of the beam properties
- Still the energy correction is the major issue
- Things will get better when the beam pickup is gone
- Local non linearity in TDC will be improved by the new algorithm (I.Alekseev/D.Svirida) This will also help the better estimation and the better measurements

- Osamu Jinnouchi RBRC

- 2/10/2005

## BackUps...

- Osamu Jinnouchi RBRC

- 2/10/2005

## The time dependence during the fill??

- BLUE 100GeV
- Eth=320keV
- 3Sigma MassCut

- The Ratio =
-  Offline/Online

- not seen a strong correlation

- Osamu Jinnouchi RBRC

- 2/10/2005

## 2sigma cut 

- 2sigma cut

- BLUE 100GeV
- Eth=320keV
- 2Sigma MassCut

- The Ratio =
-  Offline/Online

- Sigma = 1.5  2.0 GeV during a long fill
- Cut  3sigma (6.7~15.7GeV)  (5.2~17.2GeV)
-         2sigma (8.2~14.2GeV)  (7.2~15.2GeV)

- Osamu Jinnouchi RBRC

- 2/10/2005

## The effect of the cross section

- -t

- Mc +/- 5GeV cut
- Red: pulse height
- Blue: integral
- Line: N exp(-68t)
- Use integral N counts for the weights
- Degradation in high –t is from
-  Timing cut
-  variation of mass width in Energy

**Differential Cross section**

**Weighted by EXP(-68t)**

**Weighted by Event spectrum**

- Osamu Jinnouchi RBRC

- 2/10/2005