local copy: CRT phosphors original: http://www.phosphor-technology.com/crt.htm

is a link to one CRT phosphor manufacturer's page.  Notice that phosphor compounds containing Silver (compounds that contain Ag) are still being manufactured and offered for sale:
P11-BE GL47/N-C1 ZnS:Ag 0.147 0.076 6.5
P11-BE GL47/F-C1 ZnS:Ag 0.147 0.076 3.0
P20-KA GJL47/N-C1 (Zn,Cd)S:Ag 0.297 0.571 8.0
P20-KA GJL47/F-C1 (Zn,Cd)S:Ag 0.297 0.571 3.5
P20-KA GJL47/UF-C1 (Zn,Cd)S:Ag 0.297 0.571 2.1
P22-X (B) GL47/N-C2 ZnS:Ag 0.148 0.063 8.0

http://www.phosphor-technology.com/xray.htm lists x-ray production phosphors that the company manufactures.

The manufacture of these phosphors:
JGL47/L-R1 (Zn,Cd)S:Ag 20.0 RED
JGL47/S-R1 (Zn,Cd)S:Ag 10.0 RED
JGL47/F-R1 (Zn,Cd)S:Ag 6.0 RED
as phosphors intended specifically for x-ray production, ought to be internationally outlawed.

local copy: OSRAM SYLVANIA Chemical & Metallurgical Products - Phosphors for Cathode Ray Tubes original: http://www.sylvania.com/beyond/chem/cathray.htm From Sylvania (A large TV / picture tube / phosphor manufacturer, best known for light bulbs and TV sets):
1330 ZnS:Ag Blue 450 55 MS P-22, color TV1,2
1331 ZnS:Ag Blue (wide gamut) 450 55 MS Color TV, data display

Somewhat of a tutorial on CRT operation:
local copy:Winn L_ Rosch Hardware Bible, Electronic Edition, Chapter 17 original: http://viking.delmar.edu/courses/Cis312J/EBOOK/wrh17.htm

Good news: Here is a new phosphor technology that may make high voltage CRTs obsolete:

Bad news: This new technology page describes a potential problem newcomer:
"It is the goal of the phase I effort to develop direct band gap semiconducting quantum dots of CdS along with doped ZnS sots with activator ions including Ag+ and a host of transition metal ions."

Somewaht more technical backgroud as to the operating principles of and repair of television, although I'm sure there are sources that are more specific: