Comparison of 3 types of scintillator strips

and 2 types of reflector films

Miho NISHIYAMAShinshu-U

Light yield of 3 scintillator strips have been measured using -ray source.1. fiber read out strip ＋ radiant mirror film2. direct read out strip ＋ radiant mirror film3. Extruded strip (KNU) ＋ TiO2 paint

Light yield of direct read out strip with 2 types of reflector films have been measured using -ray source.1.direct read out strip ＋ radiant mirror film2.direct read out strip ＋ reflector film (manufactured by Kimoto Co. Ltd)

Size is 1 x 4.5 x 0.3 cm for all types of scintillator strips.

• Light yield of the scintillator strip is determined as:

Np.e = Mean ADC counts for -ray / d d = Signal corresponds to 1 photoelectron (ADC counts)• The parameter “d” is necessary to determine Np.e.• It has been measured with dark noise events.

Determination of the MPPC gainusing dark noise events

Clock Generator Gate Generator

AMP(x63)MPPC

ADC

Bias Voltage:78[V]

Thermostatic chamber (25 )℃

1 [kHz]

Setup

Signal input

Gateinput

d

Bias Voltage : 78 [v]

Nu

mb

er

of E

ven

ts

MPPC signal (ADC counts)

Determination of the MPPC gainusing dark noise events

Log scale

d = 25.51±0.03 (ADC counts)Gain= (6.327±0.001)×105

d

Measurement of light yieldof the scintillator strips

using -ray source

PMT

Setup

Discriminator Gate Generator

90SrMPPC

ADC

(Vbias = 78 [ V])

Trigger scintillator

Thermostatic chamber (25 )℃

Strip scintillator

Collimator with2 mmhole

Position of-ray source ×

2.25 2.25 cm

Signal input

Gateinput

MPPC

AMP (x63)

Light yield of 3 types of strip scintillatorsFiber read out Direct read out Korean extruded

fiber : Np.e = 25.0 [p.e]direct : Np.e = 18.7 [p.e]Extruded : Np.e = 12.7 [p.e]

Light yield of direct readout scintillator with 2types of reflector films

3M Radiant mirror film

Kimoto Reflector film

3M :Np.e = 22.1[p.e]

Kimoto :Np.e = 18.3[p.e]

Summary• Light yields of 3 different types of scintillator strips are : ・ Fiber read out : 25.0 photoelectrons ・ Direct read out : 18.7 photoelectrons ・ Extruded : 12.7 photoelectrons (There may be ~10% systematics from optical coupling issue)

• Extruded scintillator shows half light yield of the fiber read out strip. improvement is ongoing by KNU guys.

• Light yields of direct readout strip with 2 types of reflector films : ・ radiant mirror film : 22.1 photoelectrons　　・ reflector film by Kimoto Co.Ltd : 18.3 photoelectrons

• Results with the Kimoto film shows 82.88% light yield of results with the 3M radiant mirror film.

We may replace the 3M film with Kimoto.

Plans

• Measure light yield with position scanning

• Investigate effect of MPPC photon detection efficiency– Change bias voltage– Determine PDE from other studies

• Measure strip-by-strip variation of light yield

• Test 2 mm thick scintillator strips

Backups

Strip non-uniformity measured at DESY beam test

Kuraray strip with fiber Kuraray direct KNU strip with fiber

~75% ~66% ~48%

再現性

MPPCの取り外しあり平均 : (2.49±0.01)×102