1Satoshi Mihara ICEPP, Univ. of Tokyo Feb. 2004 MEG Review Meeting

CEX beam test at piE1

Satoshi Mihara

2Satoshi Mihara ICEPP, Univ. of Tokyo Feb. 2004 MEG Review Meeting

Elementary process

- (essentially) at rest captured on protons:

- p 0 n - p n

0

Photon spectrum

54.9 82.9 129MeV

M/2

M/2(1cos*)

M/2

*

E=55 MeV * =

3Satoshi Mihara ICEPP, Univ. of Tokyo Feb. 2004 MEG Review Meeting

Angular selection -p0n

0(28MeV/c) MeV

eV

• Requiring

FWHM = 1.3 MeV

• Requiring > 175o

FWHM = 0.3 MeV

170o

175o

0

54.9MeV 82.9MeV

1.3MeV for >170o

0.3MeV for >175o

4Satoshi Mihara ICEPP, Univ. of Tokyo Feb. 2004 MEG Review Meeting

Overview of the beam test

• 25/Sep Detector was moved to the area. evacuation

• 27/Sep- Beam tuning• 29/Sep pre-cooling• 2/Oct-5/Oct Liquefaction• 5/Oct-29/Oct Purification(gas phase)• 5/Oct- Electronics setup• 15/Oct 0 detected• 24/Oct empty target run• 1/Dec PMT amplifier study• 6/Dec Recovery• 7/Dec Cold xenon gas data for PMT

calibration

22/Sep

29/Sep

6/Oct

13/Oct

20/Oct

27/Oct

3/Nov

10/Nov

17/Nov

24/Nov

1/Dec

8/Dec

0 detected

Beam tuning

purification

pumping

Cooling/liquefaction

DAQ

~7weeks

Recovery Cold xenon gas data

5Satoshi Mihara ICEPP, Univ. of Tokyo Feb. 2004 MEG Review Meeting

• Beam line– Magic momentum (110MeV/c)– FSH52, 4mm carbon degrader (110

107MeV/c) in ASY51– 26mm carbon degrader in front of t

he target– S1 counter (40x40x5mm3) to defin

e the beam

• Area layout– The Electronics barrack placed in th

e area with concrete shielding around it.

– All controls and monitors done in the barrack.

– Liquid nitrogen supplied from a dewar located in the area.

E1 beam line

Proton beamTarget

ASY51

6Satoshi Mihara ICEPP, Univ. of Tokyo Feb. 2004 MEG Review Meeting

Setup

Carbon degrader

7Satoshi Mihara ICEPP, Univ. of Tokyo Feb. 2004 MEG Review Meeting

Hydrogen Target

• Thanks to Dr. J. Zmeskal.

• Liquid H2 cooled with a GM-refrigerator

• Temperature control

• Target cell– 0.5mm t Al

– 40mm d x 100 L

– 125cc liquid hydrogen

• Kapton foil– entrance

– exit

8Satoshi Mihara ICEPP, Univ. of Tokyo Feb. 2004 MEG Review Meeting

NaI detector

• For tagging at the opposite side of LP

• 8x8 NaI crystals– 40.6x6.3x6.3cm3

• Located 110cm from the target• Signal processor and Trigger Box

(QUAD module) to provide trigger signal

A

B

C

D

E

F

G

H

8 7 6 5 4 3 2 1

For trigger

For trigger

Base Line

Stabilizer

Attenuator

x10

x10

ADC

Trigger

Box

TDC

Crystal Array

HV

Trigger module

Differential input stage

Differentiator, Attenuator and base line stabilizer

Output stage

9Satoshi Mihara ICEPP, Univ. of Tokyo Feb. 2004 MEG Review Meeting

Timing Counter• 2 layers of

– 5cm x 5cm x 1cm BC404– Hamamatsu R5505 at both ends– 3mm t Pb plate

• 40% efficiency for 83MeV • Time resolution can be estimate

d internally.

5cm x 5cm x 1cm t

BC404

R5505

Viewed from the target

100mm

Lead collimator

TC

LPNaI

S1

TCtLP - tTC

10Satoshi Mihara ICEPP, Univ. of Tokyo Feb. 2004 MEG Review Meeting

Xenon Large Prototypeoperating condition

• Gain/QE calibration– LED and as usual

• Absorption length after 2 weeks purification abs > 140cm (90% C.L.)

(central value ~2.7m)

• Xenon extracted from the chamber is purified by passing through the getter.

• Purified xenon is returned to the chamber and liquefied again.

• Circulation speed 5-6cc/minute

11Satoshi Mihara ICEPP, Univ. of Tokyo Feb. 2004 MEG Review Meeting

Data Acquisition

• Hardware setup– ADC 3 ranges for front-face PMTs– TDC for all PMTs– PMT amplifier (x10)

• BINP• Lecce

• Software– Online MIDAS– Slow control (MSCB+LabView)

• Refrigerator control, Temp., Pressure Monitor

• Data set– Collimators in front of LP and NaI

( back to back)– Timing Counter (Pb+Scintillator) i

n front of NaI

Preamplifier Module

Av = 1

-In

+In

300

15050

CLC449

Av = +1

300

300

CLC44950

50

Av = -10

Discrete transistors

50

Av = +1

AD8001

32 Channels

8 units

Full-bandwidth Outs

Full-bandwidth Outs

12Satoshi Mihara ICEPP, Univ. of Tokyo Feb. 2004 MEG Review Meeting

Trigger

• back-to-back data– NaI : sum signal of the central 4 crystals– LP: sum signal of

• 8 PMTs on the front face & 4 PMTs on the back face

• data with opening angle < 180o

– NaI : QUAD module

• Very low threshold trigger for LP– One or two hit(s) in any one of 8 clusters

• , LED, cosmic-ray, pedestal triggers for calibration

13Satoshi Mihara ICEPP, Univ. of Tokyo Feb. 2004 MEG Review Meeting

Beam Condition• p(-)=107MeV/c

– Almost maximum separation (8nsec) of arrival time to the target between and , and between and e.

• Beam intensity– Up to 2.6 MHz @ 1800A

• Electron contamination in the beam– Negligible in triggered events

target

x=12mm

y=12mm

e

~8nsec

14Satoshi Mihara ICEPP, Univ. of Tokyo Feb. 2004 MEG Review Meeting

0 signal example

LP ADC

NaI

AD

C

LP 83 MeV

NaI 55 MeV

LP 55 MeV

NaI 83 MeV

15Satoshi Mihara ICEPP, Univ. of Tokyo Feb. 2004 MEG Review Meeting

Background Condition

• Beam on/off– PMT output for events changes, red

uced to 70% of normal values

• Not due to bleeder current because we can see the effect even with lower PMT gain.

• Background events– most probably caused by beam-relate

d neutrons,

– Energy deposit up to 9-10MeV

– Corresponding to 1.5x106 pe/sec cause this deteriorat

ion.

16Satoshi Mihara ICEPP, Univ. of Tokyo Feb. 2004 MEG Review Meeting

• CEX beam test– NaI analysis Toshiyuki– Xenon Large Prototype Analysis Ryu, Fabrizio, and …– Stability monitor …

• PMT studies Yasuko and Alessandro• TERAS beam test

– TERAS analysis Update Kenji

• Final Detector– Cryostat Fabrizio R.– Refrigerator Tom– Liquid phase purification Satoshi