Bayanin Fasaha: Hasken Dakin Duhu don Dakin Gwajin Kwanan Wata ta Hanyar Haske (Luminescence Dating)

1. Gabatarwa

Gwajin kwanan wata ta hanyar haske (Luminescence dating) wata muhimmiyar dabara ce ta ilmin kwanan tarihin ƙasa da ake amfani da ita don tantance lokacin da ya wuce tun bayan ƙwayoyin ma'adinai kamar quartz da feldspar sun kasance a ƙarƙashin hasken rana ko zafi na ƙarshe. Daidaiton wannan hanyar ya dogara ne akan ka'idar cewa tarkon electrons masu saurin haske a cikin waɗannan ma'adanai dole ne a share su gaba ɗaya (bleached) a lokacin aikin adana ƙasa na ƙarshe, kuma dole ne a kiyaye su daga haske har zuwa lokacin bincike a dakin gwaje-gwaje. Duk wani fallasa da ba a so ga haske yayin tattara samfurori ko shirya su na iya sake saita waɗannan tarkokin a wani ɓangare, wanda zai haifar da raguwar siginar haske da aka auna, kuma sakamakon haka, ƙima ƙasa da gaskiya na shekarun samfurin. Wannan bayanin fasaha ya yi cikakken bayani game da ƙira, gwaji, da tabbatar da tsarin hasken dakin duhu na musamman da aka aiwatar a Dakin Bincike na Kwanan Wata ta Hanyar Haske na Jami'ar Stony Brook, wanda aka yi niyya don rage irin wannan asarar siginar.

2. Samfuran da Kayan Aiki

Binciken ya yi amfani da haɗin samfuran daidaitattun da na halitta. Binciken kayan aiki ya kasance mabuɗi don ƙididdige halayen haske da tasirinsu.

2.1 Samfuran

• Quartz: Quartz na daidaitawa (180–250 µm, rukuni 118 & 123) da samfurin halitta (SB27) daga wurin binciken kayan tarihi na Oscurusciuto.
• Feldspar: Samfuran feldspar guda biyu masu arzikin potassium (K).

2.2 Kayan Aiki

• Ma'aunin Bakan Haske (Spectrometer): Qmini Wide VIS (AFBR-S20M2WV) mai kewayon 212–1035 nm, ana amfani dashi don auna bakan hasken fitilun da matatun haske.
• Ma'aunin Haske (Light Meter): Dr.meter LX1330B na dijital don auna matakan haske (lux) a wuraren samfuran.
• Na'urar Karanta Haske (Luminescence Reader): Kayan aikin dakin gwaje-gwaje na yau da kullun don auna siginar Haske da aka ƙarfafa ta gani (OSL) da ta Infrared (IRSL).

3. Tsarin Haske da Binciken Bakan Haske

Dakin gwaje-gwaje ya aiwatar da tsarin haske mai matakai biyu wanda aka ƙera don hasken muhalli da kuma aiki na musamman.

3.1 Hasken Muhalli

Ana samar da shi ta hanyar fitilun rufi, kowannensu yana da Fitilar LED ɗaya mai launin lemo.

3.2 Hasken da aka Keɓe don Aiki

An ɗora su a ƙarƙashin kabad ɗin bango da kuma cikin hulunan hura iska, sun ƙunshi fitilun LED na lemo masu iya dusashewa. Binciken bakan haske ya tabbatar cewa waɗannan fitilun LED na lemo suna fitar da ƙaramin haske a cikin mahimman raƙuman rawaya masu saurin sharewa ga quartz (<360 nm) da feldspar (~860 nm).

4. Sakamakon Gwaji da Asarar Sinadari (Dose)

Jigon binciken ya haɗa da fallasa samfuran ga fitilun dakin gwaje-gwaje na tsawon lokaci (har zuwa sa'o'i 24) da auna asarar siginar haske (daidai sinadari) da ta biyo baya.

Ganin cewa lokutan shirya samfurori na yau da kullun sun fi ƙanƙanta sosai fiye da sa'o'i 24, asarar siginar da aka haifar ana ɗaukarta ƙanƙanta don dalilai na kwanan wata na yau da kullun.

5. Tattaunawa da Abubuwan da ke Tattare da Shi

Binciken ya nuna cewa tsarin hasken LED na lemo da aka zaɓa a hankali yana ba da mafita mai aminci, ingantacciya, da kuma mai amfani ga ɗakunan duhu na gwajin kwanan wata ta hanyar haske. Fa'idodinsa sun haɗa da sauƙi, arha, ƙarfi, da ƙaramin fitar da zafi idan aka kwatanta da tsoffin fitilun incandescent da aka tace ko fitilun sodium vapor. Wannan tsarin yana taimakawa daidaita wani muhimmin al'amari na aikin dakin gwaje-gwaje wanda ba a ba da rahoto sosai ba, yana ba da gudummawa ga sake samar da sakamakon gwajin kwanan wata ta hanyar haske a cikin dakunan gwaje-gwaje daban-daban.

6. Cikakkun Bayanan Fasaha da Tsarin Lissafi

Gwajin kwanan wata ta hanyar haske ya dogara ne akan auna hasken da ke fitowa daga ma'adanai lokacin da aka ƙarfafa su, wanda yake daidai da adadin radiyo da aka tara tun bayan binne su. Babban lissafin shine:

$D_e = \frac{L}{S}$

Inda $D_e$ shine daidai sinadari (Gy), $L$ shine siginar haske (adadin photons da aka ƙidaya), kuma $S$ shine hankali (siginar kowace raka'a sinadari). Fallasa haske da ba a so yana rage $L$, yana haifar da ƙima ƙasa da gaskiya na $D_e$. Ana iya ƙirƙira adadin asarar siginar saboda fallasa haske kamar haka:

$\frac{dL}{dt} = -k(\lambda, I) \cdot L$

inda $k$ shine madaidaicin adadin sharewa wanda ya dogara da tsawon raƙuman haske ($\lambda$) da ƙarfi ($I$) na hasken da aka fallasa. An ƙera hasken binciken don rage $k$ a cikin yankunan bakan haske masu sauri ga quartz da feldspar.

7. Tsarin Bincike: Nazarin Lamari

Yanayi: Kimanta sabuwar kwan fitila na LED don ɗakin duhu.

1. Aunin Bakan Haske: Yi amfani da ma'aunin bakan haske don samun bakan fitar da kwan fitilar.
2. Kimanta Haɗari: A sanya bakan a kan lanƙwasa masu hankali da aka sani don quartz (kololuwar hankali <360 nm) da feldspar (kololuwar ~860 nm don IRSL). A ƙididdige hasken da ke cikin waɗannan rukunoni masu mahimmanci.
3. Gwaji na Kwarewa: Bi ka'idar da ke cikin wannan binciken: fallasa ɓangarorin quartz da feldspar na daidaitawa ga hasken na daidaitaccen tsawon lokaci (misali, 1, 4, 24 hours) a daidaitaccen nisa.
4. Lissafin Asarar Sinadari: Auna siginar OSL/IRSL na ɓangarorin da aka fallasa da na sarrafawa da ba a fallasa ba. A lissafta kashi na asarar sinadari: $\text{Asara} = (1 - \frac{D_{e,\text{an fallasa}}}{D_{e,\text{sarrafawa}}}) \times 100\%$.
5. Yanke Shawara: Idan asarar sinadari bayan matsakaicin lokacin fallasa da ake iya yiwuwa (misali, sa'o'i 8) ya kasance ƙasa da ƙa'idar da aka yarda da ita (misali, 1-2%), ana ɗaukar tushen hasken a matsayin mai aminci.