Targeting Monitor in K2K
Hiroyuki Noumi (KEK)for M. Ieiri, BCG and K2K

Contents
Primary Beam Monitors- SPIC/LS, CT/SEC
Targeting Monitor- Motivation
CT for Secondary particles- Response- Analysis
Summary

Proton Beam Monitors- SPIC/LS/CT/SEC

Profile Monitors
SPIC:Segmented parallel Plate Ionization Chamber
LS: Luminescence Screen (Cr-doped Almina Ceramic Plate)

Intensity Monitor
CT: Current Transformer
SEC: Secondary Emission Chamber (for Supplement)

Proton Beam Monitors

400m

350m
0m
70m

208m

Beam Monitors- SPIC/LS/CTSPICLSCTMonitors in the Beam PipeBeam Monitors-at the Production Target
Target HORNSECSPICSPIC
CTBeamLS
Monitors on the Slide Table

B-CT Response
Beam Line CT (BCT)
Co-ax Cable (50Ω）
Beam Line

Core:µm
N = 20 Turn

~30 dB

LeCroys
2249W

Attenuator

ADC

Counting House

M=L/N

R=50Ω≫Rc

B-CT Response (Cont.)
SignalfRF = 7.9 MHz
Raw Signal (No Attenuation)

ADC input

ADC Gate

CT signal〜1 µs~1011p/V~4×109p/pC

CT Response (Cont.)
Current Sensitivity (Calculation)

11

Output Voltage for 10 p (V)C, µm(7.9MHz) for B-CT

Core Rel. Permeability

10.9
0.8
0.7
0.6
0.50.40.3
0.2
0.1
0μm=3000μm=300μm=30μm=15μm=7μm=3.6μm=1110100
Capacitance（ｐF)

1000

10000

Targeting Monitor- Motivation
To monitor

Secondary Particles at Production
To be monitored…
Production Efficiency
Spatial Distribution
Charge Distribution}

Targeting CT

π Cherenkov Monitor for Pπ vs θπWork at Low Intensity
Need Off-line Analysis

Targeting CT-Setup

CT Layout

movable1st Horn
protons

B-CT(for Normalization)

targetCT-M
CT-L

2nd HornCT for 2ndary Particles
Targeting CTSize[mm]I.D.

O.D.

CT-L

580

600

CT-M

204224B-CT

130150Beam-Line CT

CT-L
CT-M

204mm (I.D.)
580mm (I.D.)

Test by Dummy CurrentTargeting CT-Setup (Cont.)
Targeting CT installed just behind the 1st HORN
1st Horn

CT-L
CT-M

CT
2nd HornCT Response- Horn Current DependenceMonte Carlo Simulation
Charge Flux (N+ –N-) thru CT(GEANT by T. Maruyama)

Measurement[CT-L] or [CT-M] / [EP1 CT]

1.6

CT-L
CT-M

1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0-0.20100

200Charge Flux in CT(Arbitrary)Horn Current dependence

CT-LCT-M

0150

250300Horn Current [kA]

Horn Curr. (kA)CT Response- Radial Position DependenceMonte Carlo Simulation

Measurement

Charge Flux vs CT pos.

[CT-L] or [CT-M] / [EP1 CT]

1.5

CT-L [250]CT-M [250]Target [250]

CT-L
1.0

CT-M
0.50.0

-0.5

0200

400

600

800

1000

1200

HeightDisplacement from CL (mm)Charge Flux in CT(Arbitrary)Horn Current @250 kA

CT-L

CT-M

0200 400 600

Displacement from CL (mm)CT Response- Radial Pos. Dependence in Diff. Horn Curr.
MeasurementMiddle CT [Horn Current @250 kA & 150 kA]

Large CT [Horn Current @250 kA & 150 kA]
CT-L [250]CT-L [150]1.00.5

CT-M [250]CT-M[150]

1.00.50.00.0-0.5

1.5[CT-M] / [EP1 CT][CT-L] / [EP1 CT]

1.50200

400

600

800

1000

1200

-0.50200

400

600

800

1000

1200

HeightHeight

Displacement from CL (mm)Displacement from CL (mm)CT Response- Radial Pos. Dependence in Diff. Horn Curr. (Cont.)

Charge Flux in CT(Arbitrary)Monte Carlo Simulation
Particle Contents in CT-L
at Ihorn= 250kA
CT-LIhorn=150kA
Ihorn=250kA

CT-M

0200 400 600

Displacement from CL (mm)p63%

π+30%µ+3%e+11%

Σ Pos.

107%

π−-1%µ−-0.1%

e--6%

Σ Neg.

-7%(preliminary)CT Response- Other Result

Effect of LS out (~2.5g/cm2 removed from BL)
SignalIncrease Normalized

CT-L+2.8%-2.1%

CT-M+3.2%-1.7%

Beam Transmission

+5.0%

---

Effect of Beam Incident-Angle Change
No tilt

H-tiltV-tiltCT-L

1+2%+3%CT-M

1+0.8%-2%

Summary
B-CT works fine.
- Its response can be understood well.

Targeting CT has been examined.
- CT signal increases linearly with Ihorn- Radial Dependence of CT signal was observed
Simple Charge-Flux Distribution thru CT does not explain…
… For Further Understanding of the Response, we need to consider
1. Effect of the particles hit the core…?
2. Asymmetric current source out of CT…?
3. Misunderstanding of Low-E particle affects CT…?
- Other Result
Detect the CT-L/M output change when LS out

Targeting CT works at T-Station,
having some sensitivity to the primary beam condition on TGT.
CT is potentially useful for a targeting
monitor.