Introduction to Charged-Particle Detectors - ULTRA and ULTRA-AS from ORTEC

ULTRA and ULTRA-AS
Ion-Implanted-Silicon Charged-Particle Detectors

ULTRA

• The new standard for charged-particle detector spectroscopy
• Ultra-thin entrance contact for optimum energy resolution
• High geometric efficiency due to close detector-to-can spacing
• Rugged and reliable
• Gold-plated cans for contacts that last a lifetime
• Advanced surface passivation for total device stability
• ORTEC quality and reliability
• Bakeable at 200°C (require special order)

ULTRA-AS

• Low-background version for alpha spectroscopy

ULTRA ion-implanted-silicon detectors for alpha and beta spectroscopy are the most advanced charged-particle detectors ever produced. They possess the reliability that has made ORTEC the sole supplier to NASA of silicon detectors for space applications.

Both the entrance and the back contact are ion implanted. The entrance contact is an extremely thin (~500 Å) boron implantation. Since no epoxies are used to mount the ULTRAs, the distance between the silicon surface and the top of the mounting can is <1 mm; this provides maximum geometric efficiency. The rugged front contact, easily cleaned with a solvent-moistened cotton swab, is impervious to finger contact.

ULTRA detectors have gold-plated mounting cans. The superior electrical conductivity of gold, which can never oxidize, makes it the choice vs. stainless steel or aluminum. Gold contacts last a lifetime. An advanced surface passivation that covers the critical silicon dioxide layer guarantees absolute device stability.

The extremely low leakage current permits specifying the energy resolution at a 1-µs amplifier time constant.

Low-background ULTRA-AS detectors are made with special low-background materials and have an optimized depletion thickness to minimize background counts from cosmic rays. All ORTEC Alpha Spectrometers (OCTÊTE Plus, 576A, and SOLOIST) are equipped with either ULTRA-AS detectors or R-Series, Ruggedized Surface Barrier Detectors. All these spectrometers, when equipped with a 450 mm² detector, have a warranted background performance of £24 counts per day, over the 3- to 8-MeV energy range.

The dimensions of the ULTRA and ULTRA-AS detector mounting cans, identical to those of the corresponding size A or R Series detectors, ensure that ULTRA detectors will fit perfectly in any application where A or R Series detectors are being used now.

NOTE: Extensive care regarding detector and chamber cleanliness can result in background count levels as low as 0.05 counts/hr/cm² of active area, corresponding to 6 counts/24 hours, for a 450 mm² active area.

ULTRA and ULTRA-AS detectors are normally supplied in "B" mount, with a rear Microdot connector. Other mounting arrangements are available on request. (Example: For horizontal samples in Model 576A NIM Spectrometers, a closed-back "T" mount with side-mounted Microdot connector is needed. See note below ULTRA and ULTRA-AS tables.)

Dimensions and Mounting Arrangement

B Mount

"Blind" T Mount

Detector Size (mm²)	W (Nominal)	Type B Rear Microdot			"Blind" Type T** Transmission Mount
Detector Size (mm²)	W (Nominal)	X	Y	Z	X	Y	Z
025	5.6	16.7	12.3	7.1	19.4	7.6	9.9
050	8.0	16.7	12.3	7.1	19.4	7.6	9.9
100	11.3	23.6	12.3	7.1	26.1	7.6	9.9
150	13.8	23.6	12.3	7.1	26.1	7.6	9.9
300	19.5	28.6	12.3	7.1	31.6	7.6	9.9
450	23.9	32.0	12.3	7.1	34.8	7.6	9.9
600	27.6	36.1	12.3	7.1	38.4	7.6	9.9
900	33.9	45.2	12.3	7.1
1200	40.0	48.8	12.3	7.1
2000	51.0	65.5	12.3	7.1
3000	62.0	76.2	12.3	7.1
Tolerances	±0.5	±0.3	±0.3	±0.3	±0.3	±0.3	±0.3
W, X, Y, and Z dimensions given in millimeters *Built into a Microdot connector only

Ordering Information

ULTRA Specify B or "Blind" T** Mount

Active Area (mm²)	*Guaranteed Maximum Resolution (keV FWHM)**		Minimum Depletion Depth 100 µm Model No.	*Guaranteed Maximum Resolution (keV FWHM)**		Minimum Depletion Depth 300 µm Model No.	*Guaranteed Maximum Resolution (keV FWHM)**		Minimum Depletion Depth 500 µm Model No.
Active Area (mm²)	a	b	Minimum Depletion Depth 100 µm Model No.	a	b	Minimum Depletion Depth 300 µm Model No.	a	b	Minimum Depletion Depth 500 µm Model No.
25	12 14	6 8	U-012-025-100 U-014-025-100	11 13	5 7	U-011-025-300 U-013-025-300	11 12	5 6	U-011-025-500 U-012-025-500
50	12 14	6 8	U-012-050-100 U-014-050-100	11 13	5 7	U-011-050-300 U-013-050-300	11 13	5 7	U-011-050-500 U-013-050-500
100	13 15	7 9	U-013-100-100 U-015-100-100	12 14	6 8	U-012-100-300 U-014-100-300	12 14	6 8	U-012-100-500 U-014-100-500
150	14 16	9 10	U-014-150-100 U-016-150-100	13 15	8 9	U-013-150-300 U-015-150-300	12 14	7 9	U-012-150-500 U-014-150-500
300	16 19	11 14	U-016-300-100 U-019-300-100	15 18	10 13	U-015-300-300 U-018-300-300	14 17	9 12	U-014-300-500 U-017-300-500
450	17 21	12 16	U-017-450-100 U-021-450-100	16 20	11 15	U-016-450-300 U-020-450-300	15 19	10 14	U-015-450-500 U-019-450-500
600	22 24	17 19	U-022-600-100 U-024-600-100	21 23	16 18	U-021-600-300 U-023-600-300	20 22	15 17	U-020-600-500 U-022-600-500
900	27 33	22 28	U-027-900-100 U-033-900-100	25 30	20 25	U-025-900-300 U-030-900-300	23 28	18 23	U-023-900-500 U-028-900-500
1200	35 42	30 37	U-035-1200-100 U-042-1200-100	30 37	25 32	U-030-1200-300 U-047-1200-300	28 35	23 30	U-028-1200-500 U-035-1200-500
2000	50 58	45 53	U-050-2000-100 U-058-2000-100	40 48	35 43	U-040-2000-300 U-048-2000-300	35 43	30 38	U-035-2000-500 U-043-2000-500
3000	60 70	55 65	U-060-3000-100 U-070-3000-100	55 65	50 60	U-055-3000-300 U-065-3000-300	50 60	45 55	U-050-3000-500 U-060-3000-500

ULTRA-AS Specify B or "Blind" T** Mount
~100 µm active depth to minimize cosmic background

Active Area (mm²)	*Alpha Resolution (keV FWHM at 5.486 MeV)**	Model No.
300	19	U-019-300-AS
450	20	U-020-450-AS
600	24	U-024-600-AS
900	29	U-029-900-AS
1200	37	U-037-1200-AS

*First three digits of Model No. indicate total system resolution FWHM for ²⁴¹Am, 5.486-MeV alphas, using standard ORTEC electronics and 1-µs shaping time constants.

**"Blind" T Mount available only for 300-, 450-, and 600-mm², except by special order.

To Order:

Add the appropriate letter prefix for the mounting desired.

Example: BU-016-300-100 or TU-016-300-100**


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