Compact ESR(EPR) Systems for Biodosimetry

Model No. esr34

The newly-developed spectrometer is a lightweight (27 kg) one-box ESR device with a resonator showing a Q-factor higher than that of a previous Keycom model, which is quieter, without influence from magnetic modulation, and contains a fingernail positioner.

The best measurement result obtained after the cavity Q-factor was increased to more than 7,200 by continuous polishing of the inner surface of the cavity using deerskin.

The common mode noise of “magic T” was also successfully decreased to as low as one-half by completely tuning the arm balance.
These efforts markedly decreased the noise level and extended downwardly the linear portion of dose dependence as low as 0.4 Gy.

【Related Contents】
👉 ESR measurement system

Best Suitable for Evaluation Measurement of Accumulated Absorbed Dose Published Related Paper

Development of a compact electron spin resonance system for measuring esr signals of irradiated fingernails
Suzuki, Hirosuke*; Tamukai, Kenji*; Yoshida, Naoki*; Ohya, Hiroaki*; Kato, Katsuhisa*; Anzai, Kazunori†; Swartz, Harold M.‡
Health Physics:
February 2010 - Volume 98 - Issue 2 - pp 318-321
Paper: Physically-Based Parameters
http://journals.lww.com/health-physics/Abstract/2010/02000/Development_of_A_Compact_Electron_Spin_Resonance.31.aspx

Method of Evaluation


Fig.1. Irradiation dependence of ESR signal intensity of irradiated fingernails	Fig. 2. Correlation of ESR signal intensity with irradiation dose

An ESR signal (left figure) depends on irradiation dose (left).
Its magnitude can simply estimated by the difference (height) between maximum and minimum of the signals of human nails.
Thus, the potential benefits of ESR dosimetry using human nails include the ready availability of samples for dose measurements and the capability to make immediate dose assessment.
Fingernails consist mainly of a-keratin, and the measured ESR signals appear to originate from radiation-induced radicals formed in this component [i.e., radiation-induced signals (RIS)] as well as from mechanically-induced radicals formed by clipping nails for sampling [i.e., mechanically-induced signals (MIS)].
This mechanical signal appears without irradiation.
However, MIS concentrates around cutting surfaces, clipping nails dipped into water and wipes out by paper towel.
This procedure can remarkably diminish MIS contribution.

Measurement Process

Connect on-hand PC to ESRX-10SA-v4,and power them on. ｢Adjusting Window｣ will automatically appear on the PC, and measuring process will begin.

		Mesurement window

・By「Resonator Adjust Window］resonator characteristics are adjusted, and after setting measuring conditions at 「Condition Setting Window」, all are controlled through [Measurement Window」.
・According to the object of the measurements, some integration, accumulation, adjustment of blank data etc. moving average can be selected, as required.
・Data processing such as peak height(h), first and second Integration are selected as required. ・This system can automatically correct the magnetic field by using the position of the ESR signals of Mn2+ (option)

Model No.

ESRX-10SA-v4
* Windows PC is not included.

Specifications

Sample tube (standard)	Quartz sample tube (5mm o.d).
Sampling setting	Sample holder and stopper
MW frequency	9.8 GHz (JIS)
MW power	2-10 mW (JIS)
mag.field Setting	350 mT
Field sweeping	16 mT (JIS)
Field sweeping speed	0.5, 1, 2, 5, 10 min
Signal amplification	Analog amplification: x1, x10, x100, x1000 (4-step switch), Digital amplification: x1, x2, x5 (3-step switch)
Signal output range	± 10 V
PC requirements	Windows PC, Data recorded in CSV format
Size	28(W) × 26(D) × 35(H) cm
Weight	c.a. 27 kg
Source (standard)	AC 100 V, 120 W max.