BORON-GEM3 – FURTHER MEASUREMENTS
19.03.2014
Dorothea Pfeiffer
Content
2
X-ray spectrum of 241 AmBe source
 Neutron spectrum measured with BoronGEM3 with 8 mm drift
 Mesaurements with SRS
 What’s next?

Dorothea Pfeiffer
19.03.2014
Measurements with AMPTEK XR-100CR
Si-PIN X-Ray detector
3
5.9 keV
6.49 keV
Efficiency of AMPTEK XR-100CR
Si-PIN X-Ray detector (500 um Si, 1 mm Be)
4
Dorothea Pfeiffer
19.03.2014
241 Am example spectrum AMPTEK XR-100CR
Si-PIN X-Ray detector
5
Measurements with AMPTEK XR-100CR
Si-PIN X-Ray detector (efficiency corrected)
6
13.95 keV
17.74 keV
59.54 keV
Triple GEM with Boron-10 converter (variant 2)
7
Drift cathode:
18 um Al foil coated
with 1.3 um10B4C
one side
8 mm
2 mm
2 mm
2 mm
Dorothea Pfeiffer
19.03.2014
Boron GEM3: 18 um Al foil with 1.3 um 10B4C
8
y coordinate
(APV chips not connected)
x coordinate
(APV chips not connected)
Dorothea Pfeiffer
19.03.2014
55 Fe spectrum
9
ADC channel 50 at preamp gain 10
= about channel 25 at preamp gain 5 ?
241 AmBe spectrum, drift gap 8 mm
10
ADC channel 2800
(~ 672 keV)
Li peak 840 keV)
ADC channel 5000
(~ 1.2 MeV)
alpha peak 1.47 MeV
Spectrum from Boron Blade Detector at ILL
11
Looks similar to our spectrum, also only one
peak (not two peaks for alpha and Li ion)
Dorothea Pfeiffer
19.03.2014
Boron GEM3: two sectors:
with and without 18 um Al foil with 1.3 um 10B4C
12
1 cm of lead covering
whole detector
Normal cathode on top
1
2
y
Sector 1: 1 cm lead
Sector 2: 10B4C
converter and 1 cm lead
Dorothea Pfeiffer
x
19.03.2014
Boron GEM3: two sectors – 55 Fe source
13
1
Looks similar to our spectrum, also only one
peak (not two peaks for alpha and Li ion)
2
Boron GEM3: two sectors – 55 Fe source
14
1
Looks similar to our spectrum, also only one
peak (not two peaks for alpha and Li ion)
2
Boron GEM3: two sectors – 55 Fe source
15
1: x
1: y
Spectra in sector 2 have 50% of the hits
2: x
2: y
Boron GEM3: two sectors – 55 Fe source
16
1: x
1: y
Cut in sector 2, x=4: Kapton tape? But in y?
2: x
2: y
Boron GEM3: two sectors – 241AmBe source
17


Due to limited
dynamic range of
the APV,
measurement had to
be carried out with
very low gain of
about 15 (I=565 uA,
U=3250 V)
Even then saturation
visible
Dorothea Pfeiffer
saturation
19.03.2014
Boron GEM3: two sectors – 241AmBe source
18
1
Looks similar to our spectrum, also only one
peak (not two peaks for alpha and Li ion)
2
Boron GEM3: two sectors – 241AmBe source
19
1
Looks similar to our spectrum, also only one
peak (not two peaks for alpha and Li ion)
2
Boron GEM3: two sectors – 241AmBe source
20
Sector1
+
2
Looks similar to our spectrum, also only one
peak (not two peaks for alpha and Li ion)
Boron GEM3: two sectors – 241AmBe source
21
Looks similar to our spectrum, also only one
peak (not two peaks for alpha and Li ion)
sector1
Boron GEM3: two sectors – 241AmBe source
22
Looks similar to our spectrum, also only one
peak (not two peaks for alpha and Li ion)
sector2
Boron GEM3: two sectors – 241 AmBe source
23
1: x
1: y
2: x
2: y
Boron GEM3: two sectors – 241 AmBe source
24
1: x
1: y
Spectra in sector 2 have 2% of the hits compared to sector 1
2: x
2: y
Boron GEM3: two sectors – 241 AmBe source
25
Calculation of “neutron spectra”: sector 2 – sector 1
6Li peak and alpha peak? Energy calibration with APVs and SRS?
Dorothea Pfeiffer
19.03.2014
Boron GEM3: two sectors – 241 AmBe source
26
1: x
1: y
Source not perfectly centered on detector
2: x
2: y
Boron GEM3: Four sectors
27
Sector 1: free (normal
GEM)
Sector 2: 1 cm lead
1 cm of lead
Sector 3: 10B4C
converter
1
3
2
Dorothea Pfeiffer
4
x
y
Sector 4: 10B4C
converter and 1 cm lead
19.03.2014
Boron GEM3: Four sectors
28
2 sector measurements
4 sector measurements
Problem with one of the APVs apparent at the end of the
measurement, but also variability very large in first part of dataset
(event number < 150000) => repeat measurements
Dorothea Pfeiffer
19.03.2014
TO DO
29
Measure X-ray spectrum of 241 AmBe
source with lead in front
 Measure gamma spectrum of 241 AmBe
with Sodium Iodide chrystal
 Repeat 4 sector measurement with SRS
 Organize Gadolinium samples

Dorothea Pfeiffer
19.03.2014