Status Report for KEK-PS E391a

KEK IPNS

G.Y.Lim

14 April 2003

E391a experiment

Measurement of BR( KL ) Collaboration

High Energy Accelerator Research Organization, KEK

Faculty of Science and Engineering, Saga University

Department of Physics, Yamagata University

Department of Physics, Osaka University

Research Center for Nuclear Physics, Osaka University

National Defense Academy of Japan

Joint Institute for Nuclear Research (Dubna) Russia

Department of Physics, University of Chicago, USA

Fermi National Accelerator Laboratory, USA

Department of Physics, Pusan National University, KOREA

New KEK member

Department of Physics, Kyoto University

Data taking from Feb. 2004 Engineering run Preparation of detector components

Two-step program (KEK-PSJPARC)

From the E391aEstablish measurement principleSearch for near SM expectation

E391a Detector

Upstream section

Downstream section

Middle Section

Engineering Run on last winter

Engineering Run

Fabricate on last summer

KL decay data – same format of real run

Develop on-line/off-line software

DAQ using self-trigger of CsI

Same scheme of real run

Tuning / feed-back CsI calibration

Cosmic test in vacuum chamberCosmic test during stackingPunch-through muon Two gammas from single 0

Multi-gamma decay (Kpi2, Kpi3)

Significant step to the successful experiment

DAQ with low noise level

Distributed and parallel processing LeCroy 1885N FASTBUS ADC TKO HR-TDC Operation with tiny noise

1mV threshold for TDC ( 1 MeV) 50 fC ADC pedestal (0.1 MeV)

Calibration using cosmic/punch-through muon

Using cosmic rays

pQpQ/cm

Using punch-through muons

CsI IDCsI ID

MeV

/pQ

Good agreement between two gain factors !

Calibration using 0-production

n

Before correctionBefore correction After correctionAfter correction

Reconstructed

position(cm)

Incident position (cm)

Incident position (cm)

Two invariant mass (MeV/c2 )

Two invariant mass (MeV/c2 )

m : 5.4 MeV/c 3.7 MeV/c

22

Study using Kpi3 decay

Calibration method in real run

How to get correct energy scale

Background free without veto system

Comparison with M.C.

Detailed study is going on

Radial hit distribution of gamma Vertex along the beam direction

- Good agreement

Short spill beam (1X1012 ppp/ 200 ms) Single counting rates (10 mV Thres.)

Response at the high Intensity

PMT gain (Xe monitoring system)

KTeV CsI

0

2

4

6

8

10

12

14

1 2 3 4 5 6 7 8

CC03

0

10

20

30

40

50

60

70

1 2 3 4 5 6

KTeV CsI

CC03

Cou

nts

/ SE

C

Inner CsI

0

1

2

3

4

5

6

7

8

9

1 2 3 4 5 6 7 8

Outer CsI

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1 2 3 4 5 6 7 8

Outer CsI

Inner CsI

7.0 X 1011 / 2s

1.4 X 1012 /2s

1.0 X 1012 / 0.2sADC channels

Xe signal of the 1st CsI module

Nor

mal

ize

cou

nts

On spillOff spill

Peak=1437/Mean=1.6%

Ratio of on/off spill for Xe-peak1.05

1.0

0.95

CsI ID

Same performance under the high beam

Same performance under the high beam

intensity

intensity

Detector fabrication – Upstream

Modules/vacuum chamber doneCosmic test is going on

No.

of

p.e.

/ M

eV

Distance from the PMT (cm)

Assembling on June -July

Assembling jigs are being fabricated

- KEK machine shop

Detector fabrication – Middle

Fabrication of 3 modules ー　 Finished

1 module/1 week End of Oct. (32 modules)

Design of assembling jigs – final stage

Assembling Nov. – Dec.

Vacuum Chamber : Start bidding process

arrive at the end of Oct.

Schedule

2001 2002 2003 2004

Data Taking

Assembling Detector setup

Vacuum &

Cosmic Test Assembling

Front barrel Construction

Main barrelConstruction

Cosmic Run

Beam survey Engineering Run

Jan. Apr. Jul. Oct. Jan. Apr. Jul. Oct. Jan. Apr. Jul. Oct. Jan. Apr. Jul. Oct.

CsI

Cosmic Run

AssemblingUpstream section

Front barrel Design

Central barrel Design

Up-dated on April, 2003

Evacuating Test

Summary

E391a is aiming for measuring the BR( KL ) Realizing Step-by-step

Engineering run Stable data taking using same triggering scheme of real run CsI calibration – cosmic ray data is very nice input No problem at high beam intensity Good agreement with M.C. Detailed study is going on

E391a is preparing almost on schedule Downstream section is polishing stage Upstream/middle section – being fabricated smoothly Prompt start at the real run (Feb. – June, 2004)Prompt start at the real run (Feb. – June, 2004)

- Full beam acceptable- Full beam acceptable