Re: I HpGe
Inviato: 22/07/2019, 9:24
Attenzione!
Per quelli interessati ad acquistare questo tipo di detector sulla baia e' bene a sapere [External Link Removed for Guests] detaglio che riporto dal forum elencato sopra:
"To Buyers on E-bay.
Many sellers, in the know loot the germanium slug on such systems. I know I did on two of the GeLi detectors I had. These slugs are huge and can weigh nearly one pound. That is about $250.00 worth of Ge. Some sellers then reassemble and sell the slug to any number of on line buyers of Ge and then place the cool instrument on e-bay with the usual disclaimer "sold as is", "not returnable", be sure before you buy. I figure about half of the sellers know that they have a $200.00++ block of Ge, at scrap, in there and the others don't.
Just a warning from an old scrapper of surplus goods.
You can't fry the Ge crystal without using a lightning bolt.
For those who have never ripped into a classic GeLi detector system, the Crystal (slug) and the front end FET are often in contact with a copper cold finger of some mass placed in a dewar of LN2. The finger usually passes coaxially through the hollowed out cylindrical crystal. This finger is usually in a vacuumed out sleeve to reduce conduction of heat. Likewise, the FET and Ge slug are under vacuum for the same reason. The FET's gate lead is just marginally in contact with one end of the slug The other end is case grounded, usually. I have never seen a preamp that was cooled; just the front end FET for noise reduction."
Questo infortunio sembra di essere capitato ad un altro appassionato italiano. Per evitare questo tipo di sorpresa forse bisogna chiedere più informazioni al venditore tipo il peso totale.
Se mancano pezzi dalla zona "endcap" potrebbe essere un indicazione della mancanza del cristallo di Ge!
Per quelli interessati ad acquistare questo tipo di detector sulla baia e' bene a sapere [External Link Removed for Guests] detaglio che riporto dal forum elencato sopra:
"To Buyers on E-bay.
Many sellers, in the know loot the germanium slug on such systems. I know I did on two of the GeLi detectors I had. These slugs are huge and can weigh nearly one pound. That is about $250.00 worth of Ge. Some sellers then reassemble and sell the slug to any number of on line buyers of Ge and then place the cool instrument on e-bay with the usual disclaimer "sold as is", "not returnable", be sure before you buy. I figure about half of the sellers know that they have a $200.00++ block of Ge, at scrap, in there and the others don't.
Just a warning from an old scrapper of surplus goods.
You can't fry the Ge crystal without using a lightning bolt.
For those who have never ripped into a classic GeLi detector system, the Crystal (slug) and the front end FET are often in contact with a copper cold finger of some mass placed in a dewar of LN2. The finger usually passes coaxially through the hollowed out cylindrical crystal. This finger is usually in a vacuumed out sleeve to reduce conduction of heat. Likewise, the FET and Ge slug are under vacuum for the same reason. The FET's gate lead is just marginally in contact with one end of the slug The other end is case grounded, usually. I have never seen a preamp that was cooled; just the front end FET for noise reduction."
Questo infortunio sembra di essere capitato ad un altro appassionato italiano. Per evitare questo tipo di sorpresa forse bisogna chiedere più informazioni al venditore tipo il peso totale.
Se mancano pezzi dalla zona "endcap" potrebbe essere un indicazione della mancanza del cristallo di Ge!