Détecteurs semi-conducteurs HPGe et Si(Li)

Galerie et schémas techniques

Description

Caractéristiques

• Très large choix de détecteurs
• Détecteurs HPGe (type N ou P) ou SiLi
• Large gamme d’énergie de 3Kev à 10MeV

Spécifications techniques

U

25.6* Bi ( U) 727.2

GEM

P coaxial

GLP

P planaire

GMX

N coaxial

GWL

P coaxial reverse

SLP

Si(Li) planaire

keV

Diameter @5.9 keV

PIXE

SLP, IGLET, IGLET-X

Well

0.3 Ion 10 keV–10 P-type HPGe Up to 400 2.10–2.30 keV Yes

ORTEC

Thickness Energy Standard* Energy Peak to Temperature

GEM-FX

Nominal Eff. @122 keV

GEM-MX

Nominal Eff. @122 keV

Planar

0.1 1 keV–30 keV Lithium 4–16 mm 160–250 eV Yes

Window

Implanted Diameter @5.9 keV

214 238

208 232

Coaxial

585–720 eV

PROFILE

38%–175% 900–1300 eV

Pb ( U)

46.5 Ac ( Th) 911.0

Special

<0.1 <1 keV–>60 P-type HPGe 6–16 mm 135–160 eV Yes

Type of

Window Useful Standard* Standard* Standard Peak Shapes Warranted

Detector

Geometry (μm) Range Material Sizes Resolutions Compton FW.1M/FWHM FW.02M/FWHM Cyclable

Diameter

@5.9 keV

Tl ( Tl)

583.1 Bi ( U) 1764.5

U x-rays

13.0, 13.3* Cs 661.6

Implanted

Diameter @5.9 keV

PROFILE C

P coaxial

235U, 226Ra

185.7, 186.2 214Bi (238U) 1120.3

Application

Most Suitable Detector(s)

Short Thin-

0.3 Ion 3 keV–1 MeV N-type HPGe 36–70 mm 300–495 eV Yes

Waste assay

Micro-trans-SPEC, trans-SPEC-DX-100T, GEM, GMX

214Pb (238U)

351.9 60Co 1332.5

234Th (238U)

63.3 228Ac (232Th) 969.0

212Pb (232Th)

238.6 60Co 1173.0

PROFILE GEM F

P semi-plan

PROFILE GEM M

P coaxial

PROFILE GEM S

P semi-plan

CSS Advantages

For a given HPGe detector, a CSS will always reduce Compton

PROFILE GEM SP

P semi-plan

Lung monitoring

Actinide-85

CSS Disadvantages

The sample size is usually small because the sample must be

I = I0e–μ(E) X

(2)

Cryostat Materials

Fig. 18. View of GAMMASPHERE with Right Half Removed.

Coaxial 700 (sides)

MeV Diameter @14.4 keV

Detector Efficiency

ε(E)

10. See, for example

R. Keyser, T. Twomey, S. Haywood, W. E. Parker, T.F. Wang, D. Clark, K. Raschke, W.Romine, W. Buckley and

Famille de détécteur

Type

Freight/Border Security

Micro-Detective, Detective-EX, Detective-DX, IDM

The Analyzable Spectrum

Good Data vs. BAD Data

Drifted Silicon Diameter

@5.9 keV

Post-accident monitoring

GEM (PLUS option recommended)

choice of configurations.

137

Neutron activation analysis

GMX (PLUS option recommended)

Small environmental samples

GWL (low-background recommended)

High-grade fissile materials

SGD, SGD-GEM

Sea or airborne surveillance

Micro-trans-SPEC, trans-SPEC-DX-100T, IDM

Détecteur spécial Safeguard GEM

P coaxial

In-Situ environmental spectroscopy

Micro-trans-SPEC, trans-SPEC-DX-100T, GEM, GMX

MDA (E) ~ SQRT [R (E) B (E)]/ε(E)

(1)

Compton-suppressed gamma spectroscopy

GMX, GEM (based on range of energy interest)

If the answer is no, consider this next

Will the count rates of the 231 214 238

specified energy. ε(E) will depend on the

Figure 7. Point source efficiency curves for planar

Large environmental samples with complex spectra

GEM, GEM-F, GEM-M, GEM-MX, GMX, (low-background recommended)

placed inside the NaI annulus. The system is complex

coincidence electronics require

GMX however would cost significantly more, and for the

P-type (GEM). (Point source at 25 cm.)

human lung measurements, a high contributor to Compton

137 241

Synchrotron light studies; Soft x-ray (fusion) research

IGLET, IGLET-X, SLP, GLP

Because both detectors greatly exceed the diameter of the

point source geometry.

person’s bones. This cannot be reduced by the detector.

ratio, improving MDA.

where the quantity of sample is very small, e.g., in some

Figure 13. Disk and “wrap-around’ geometries compared.

PROFILE GEM-MX can provide good efficiency for 241Am). The

Figure 9. Comparison of absolute efficiency of an N-type (GMX) and a

the 120% are almost 3 times as large as those from the 12%

Figure 16. 12% uncollimated and 120% collimated detectors compared at the

background is the natural 40K gamma rays scattering from the

relative efficiency GMX detectors, showing the effect of increasing P:C

presented to the detector, this will also add to the general

detectors.

(Ref. 3)? Yes and no! More efficiency will always improve the

Figure 3. Background counts vs. detector volume for a large number of

example of the reduction in background count rate that can be

234Th (238U) 92.6 234mPa (238U) 1001.0

lower the MDA, but the same amount of investment in a higher-

Cosmic 511.0 40K 1460.8

present. As soon as a sample source with non-zero activity is

Figure 4. Peak to Compton ratio vs. relative efficiency for coaxial P-type

background counts created by the radioactive isotopes that are

Cs 31.8, 32.2, 36.4* Pa ( U) 766.6

the sample as if it is on the face of the endcap. However, when

Figure 12. 1 L and 2 L Marinelli Beakers compared to 1 L bottle on endcap

you consider gamma rays emitted at an angle, the curved surface

for a GMX detector.

efficiency detector will produce about the same MDA improvement.

208 232 214 238

lines at energies above 1500 keV, a low-background cryostat is of

* The lines lower than 46 keV are reported only for LO-AX and GMX detectors.

Closed-End 700 40 keV–10 P-type HPGe 10%–150% 175–240 keV 37

1–90:1 1.90–2.00 2.65–3.10 Yes

Closed-End 700 40 keV–10 P-type HPGe 59–90 mm 675–1300 eV 40

1–90:1 1.90–2.00 2.65–3.10 Yes

If the answer is yes, then a Low- or Extra-Low-background detector

Isotope Energy Isotope Energy

beaker. However, and it is important, if there is enough sample to

Figure 11. Comparison of 1 L and 2 L Marinelli beakers on the same detector.

detection limit reached in a given count time. However, you should

detectors.

is needed to achieve detection limits. It can be provided in a wide

(Parent Nuclide) in keV (Parent Nuclide) in keV

the reset of the preamplifier (if not resistive), defines the system

Figure 15. System throughput curves.

1500 keV, and little better above that. If your peaks of interest are

214Pb (238U) 295.2 214Bi (238U) 1238.0

detector will produce the best possible results.) For measurements of

Bi ( U) 609.3 Tl ( Tl) 2614.5

present at low levels in a standard cryostat?* If the answer to this 210

238 228 232

Closed-End <15 (face) 10 keV–10 P-type HPGe 59–94 mm 800–1280 eV 62

1–90:1 Yes

Closed-End <15 (face) 10 keV–3 MeV P-type HPGe 58–85 mm 485–600 eV 35

1–55:1 Yes

Thin Window 0.3 Ion 3 keV–10 MeV N-type HPGe 10%–100% 1.90–2.65 keV 38

1–64:1 1.90–2.30 2.65–3.30 Yes

Applications

• Spectrométrie nucleaire
• Sécurité du territoire
• Médecine

Conformités et normes